Watch And Listen How A Subaru Engine Rod Knock Vs Piston Slap Sounds Like

[@pavoutsinas]

The New York accent shined through over that rod knock 👍 best comparison video online. thank you!

[@motorcarnut]

Glad you liked it!

[@alfredjamesdelgado2037]

my 3 cylinder 1 litre engine with only 50k miles is already having piston slap.. Watching this video makes me feel good its not bad as the rod knock Thanks man

[@motorcarnut]

Sure, no problem!

[@abbe6305]

@@motorcarnut this one kzbin.infoYF_GJtsoCt0 piston slap`?

[@motorcarnut]

No just responded to you

[@NotSoTypicalGamer]

So basically - if the sound doesn't go away when it's warm - it's likely a knock rather than slap. This was very helpful as I'm new to boxer motors so thanks for sharing.

[@motorcarnut]

Yes, exactly. Glad to help!

[@reidthompson8979]

Thanks for the video!! My Honda B20 has some bottom end tapping when the coolant is warmed up enough for the idle rpm to drop lower but the oil and metal isn’t very warm yet, and I was 98% sure it was piston slap (fairly common on the B series engines) because its never complained about me wrapping it out to 7000+ rpm, and this confirmed that and put my rod knock fears aside. Thanks!

[@motorcarnut]

Thank you for the comment. Yep seems like that to me too from what you explained.

[@refridgeratorimation]

Thanks for this video. Went to test drive a Subie with a sound that made me wonder is it a complete disaster, but this video cleared it a little bit for me.

[@motorcarnut]

Sure, No problem! Good Luck!

[@Tomas.X]

Picked up a rust-free 2006 Impreza 2.5i 6 months ago for my son. It had a rattle on start-up, and some noises, classic Subaru, they're all I drive. Now, he is gone all the time and I see and hear it infrequently. But when I heard it idle at times, I thought it sounded worse. I changed the oil, but no change in sound. I had access to the car just after Christmas and the loud tapping/knocking occurred in the following cycle: Distinct at idle, increased upon accellerating, then gone while cruising along. When letting off the gas to coast approaching a stop sign, the noise returns when it gets to 25 mph > idle. The local Subaru specialist had it today for some other things, and he checked the sound, confirmed no exhaust leaks, and suggested rod knock. When I drove it home, I wasn't sure if I'm now oversensitive or if the symptoms described were far more pronounced. Never had this with any of my Subaru's. Any opinions?

[@motorcarnut]

From what you’re describing it’s not really going away when fully hot so it’s probably a rod letting go. You can try to put some oil treatment like STP in there just to see if it gets more quiet,if it does then the rod bearings are failing.

[@Tomas.X]

@@motorcarnutThanks for responding. I like my Subaru specialist mechanic, but we seem to have communication issues. Long story short, this knocking sound was apparently "quite pronounced" at the shop yesterday (and when I drove home, he was right, it was much worse than when I drove it there the day before.) I changed the oil last night and ran a big magnet around, and there was some tiny metal bits, but nothing dramatic. The "communication issue" I referred to was a chat a couple months ago when he believed a coolant leak was my HG...but it was the radiator. It has not overheated at all. But he recommended yesterday new block and heads, citing "danger" the heads may have warped from overheating "at some point". I could order a long block...would save the machine work the shop would do...but it comes with a new timing belt kit, which means losing the money I just invested 24 hours ago. I should also note this guy lost his long-time machinist that did block/head surfaces...but he "could find someone" to do it. But again, he's rather hung up on the "get new heads" advice. So is there any reason to bit the bullet and just get a long block? (Maybe I could arrange a long block w/o a timing belt kit...but doubt that's possible because most engine shops pre-run the engine before shipping it out.) Thanks for the advice...dealt with so many thinigs but this (especially with a non-turbo) is all new to me.

[@motorcarnut]

@tomasx9027 If the car is worth it to you and makes sense money wise a long block would be the best bet, less labor to rebuild your old one and should come with a warranty. Timing kit you have just keep it as a spare.

[@mjjeverything7912]

Or just throw so new bearings in UT if the cranks isn't chewed up to much.

[@M4TCH3SM4L0N3]

Thank you so much for this very practical and helpful video! It's so frustrating sifting through all the junk information on the internet, but finally finding a video with the actual sounds was completely worth it.

[@motorcarnut]

You are so welcome! And appreciated as well!

[@vihreelinja4743]

Thanks. My subie definitely do NOT have a rod knock. Perfect explanation.

[@motorcarnut]

Great! And thanks for the feedback.

[@MrCWoodhouse]

Thank you Sir. I was able to identify the rod knock in a 2016 Kia at the used car lot. Didn't buy the car, of course, thanks to your video.

[@motorcarnut]

That’s great and exactly what I like to hear. No body getting scammed!

[@jve89]

Good video. I just seized my 2008 Subaru Impreza 2.0 engine completely. The mechanic had just a quick look because it was not worth it to do a full inspection but he thought the crankshaft cracked. It made the knocking sound as well before it seized. It already used excessive amounts of oil for months. Fixing it would break the bank so I'll bring it to the scrapyard.

[@motorcarnut]

Thank you! Sorry to hear that, if the vehicle is worth fixing, i have videos on rebuilding or replacing engine.

[@BourneThisWay]

This first sound is what my GTR is making, but more mild. I didn’t hear it in the middle of summer when it was pushing 100 degrees, but as it’s cooling up now in the fall, I’m hearing it more often and it goes away when it warms up.

[@motorcarnut]

Could be piston slap because it goes away when warm. Metal expands when hot so that's why in the summer you don't really hear it. I wouldn't worry too much as long as it goes away when at operating temperature.

[@hhaste]

Does it have forged pistons? When I first had forged pistons installed in my STi, it had some piston slap whenever it was lower than 50 degrees outside but over time, it completely went away. It may also need a different oil weight for winter vs summer.

[@motorcarnut]

@hhaste Forged piston will make a louder sound because of the material they are made from.

[@moorefab8192]

This is exactly right. I just built a 2008 2.5 SOHC engine using a good 2001 block and crank. Good used 2008 rods and new 2008 pistons. I put new rod bearings in but couldn’t get a good set of main bearings anywhere so I opted to use the old ones that were in very good shape. I plasti gauged all the bearings and they were all perfectly in spec. The wrist pins to small rod end were perfectly in spec. The new pistons had about 8 thou of piston to bore clearance which was a ways out of spec but I decided to give it a go since the ring end gap was good. The heads are rebuilt and surfaced. Anyway, what I’m getting at, is it had a small knock like the first example but not near as loud and it worried me but I know for sure it couldn’t have been rods because I went through all them. I know the pistons were sloppy so that’s gotta be what it is. Goes away when warm or when reved.

[@motorcarnut]

Yep, exactly right!

[@2a.m.tacobellrun333]

Bought a 2015 legacy 2.5i a little over a year ago. Bought it at 108000 now has 145000. Engine gets a little loud when cold starting. Michigan weather for reference. Obviously cars hate cold weather but hearing what a problematic boxer sounds like helps a lot. Now i know what to look for in case something is actually wrong. That being said, these engines are noisy for a 4 cylinder

[@motorcarnut]

Yes, they are. I don’t like it as a mechanic but had many over the years and were very reliable.

[@thatman4752]

You forgot to rev the engine knock so we can hear the difference.

[@scoobysean555]

Damage the crank even more 😂 you seen the price of cranks

[@44sandstorm]

Thank you for showing both! I don't have a Subaru but my Sebring is making a similar noise (210k miles) to the piston knock. Hopefully that's what it is but I guess I'll find out LOL

[@motorcarnut]

Good luck!

[@mrmotorvator5151]

Unplug the coilpack..rodknock will stop due to the lack of force on rod,, pistonslap will not

[@motorcarnut]

@mrmotorvator5151 yes and no. If the rod knock is bad enough it won’t matter

[@captivabreed176]

Great video, my suggestion would have been to add the valve tick noise for the third option of what a lot of Subaru owners hear

[@motorcarnut]

I’ll make one of those when i get one in.

[@Kragum24]

I have a 2023 Crosstrek with a 2.0 liter motor, with 20,000 miles on it and it runs like a top, and the motor is about as noisy as a top! Those 2.5 liter engines can start ticking and making other engine noises shortly after purchase, and most will eventually become noisy. If you want the little extra horsepower and torque that the 2.5 liter offers, you might have to tolerate some annoying engine noise(s) for the life of the vehicle. Not worth it! My 2.0 liter has 20,000 miles and is super quiet, even on start up. I'll take the smaller, quiet 2.0 liter motor, over the bigger, junky sounding 2.5 liter motor any day.

[@motorcarnut]

@Kragum24 yours will make noise soon too. They all do at some point.

[@savannahlatimer1595]

my 2011 Subaru forester makes the first sound when it starts but sometimes when I accelerate, especially after a long drive, it makes this loud fan/slapping sound but it quiets over 45mph

[@motorcarnut]

That sounds like a piston slap that got worse to me.

[@HiFiInsider]

does using higher viscosity engine oil helps with the pistol slap. my hyundai has this noise when cold. i was thinking to go 10W-30 from 5W-20.

[@motorcarnut]

You can try it but I don't think it will make much difference because not much oil gets up there in between the cylinder walls and piston skirt.

[@seansteyn8421]

Thanks for this, my car is making the piston slap sound and I was VERY concerned!

[@motorcarnut]

No problem.

[@MrSpandexy]

Anybody out there scared their vehicle is done.... I got a huge knock as my exhaust manifold separated from the block. I think both back pressure and small exhaust leak made it so loud. I lifted the front and one manifold nut was gone. The other was on it's way. Tightened and realized that was it. New gaskets for 10 bucks from NAPA and all is great. Yay

[@motorcarnut]

That would be a different noise but for the average person maybe not, great fix, maybe will help others! Thank you!

[@alphaheartblack]

You don't have an example on a 6.4 hemi, my SRT jeep makes a sound similar to that but I can't tell it apart, it does disappear a bit when I accelerate

[@motorcarnut]

Make a video on your channel and ill give a listen.

[@alphaheartblack]

I upload video

[@motorcarnut]

That does sound like a rod knock to me because it was louder under the vehicle. Sometimes the serpentine belt tensioner can have a sound like that too.If you take off the belt and start the vehicle and it still have that noise then you know its not the tensioner.

[@alphaheartblack]

​@@motorcarnutok I try that

[@Onkelcem]

my Golf 4 1.4L sounds like piston slap, if you say i have nothing to worry i believe you :D i got the car since 160.000km, now it has 185.000km. I will do an oilchange, maybe it helps :D 5w40 or something

[@motorcarnut]

Actually this is normal for Subaru’s but if yours is not getting worse you should be fine in what you are going to do.

[@alexandermeira7351]

have you never done an oil change in 25.000km?!

[@Onkelcem]

@@alexandermeira7351 long life oil change 30000 km, sry if im wrong

[@KingIsBored]

my first car was burning oil and i had no idea, so one day my engine exploded on the highway, and it was very loud knocking sound. now 10 years later, im facing a problem with my hyundai kona 2020 burning oil, keep adding more every few days

[@motorcarnut]

Those engines are under a recall for free replacement you may want to contact Hyundai

[@zandercook1494]

My knocking becomes present as soon as I reach 30mph. I’m assuming it’s either low oil (I’m 800 miles from needing a change, but I drive short distances a lot), or rod knock. What do you think?

[@zandercook1494]

It also gets louder as I increase in speed

[@motorcarnut]

It does sound like a rod knock to me from what you just described. You shouldn't drive the vehicle with low oil either, its very easy to check and top off if necessary

[@motorcarnut]

Yes, just answered above.

[@teecee1464]

So incredibly helpful! Thank you ❤

[@motorcarnut]

You're so welcome! And very appreciated feedback!

[@462ANIMAL]

I have a 09 forester , 2.5 L Na. It has a tick on cold start up, goes away in 2 minutes or so.. then back when at operating temperature.. I’m hoping it’s just a exhaust valve needing adjustment or an exhaust leak at the cylinder head.

[@motorcarnut]

The valves in the engine are adjustable so very well may have to be adjusted.

[@abhi5655]

Is it ok with ford freestyle..or should i concenrd about this...and can you explain this . Why this piston slap happn and what is the solution for this...specially in cold weather.

[@motorcarnut]

It’s not normal and happens when vehicle overheats, lack of oil debris entering the engine and in rare cases poor engine build from factory or aftermarket. The solution is a rebuild of the engine block and pistons. Big job.

[@bryanwillis7726]

My 15 Legacy is nice and quiet with 125,000 miles on it. My wifes 18 Legacy with 70,000 is loud. I treat them the same except, I take the time to warm up the engine, she doesn’t. People say warming up an engine is useless?

[@motorcarnut]

No it's not, As I explained in another video and you are experiencing, some Subarus make noise some don't but considered normal. Warming it up is key to longevity either if it makes noise or doesn't.

[@ronburdick5346]

Thank you , very informative 👍

[@motorcarnut]

You're welcome! Glad to hear it was helpful. Appreciate the feedback!

[@EternalSilence4ever]

Thank you so much for helping me distinguish what an engine knock sounds like - and what a Subaru engine sounds like hahaha.

[@motorcarnut]

Glad to help!

[@RockyRoad878]

If it was a rod knock would the Engine light be on? My engine light is not on and I’m up to date with oil changes. I’m just still having trouble hearing the difference between the two

[@motorcarnut]

No it doesn’t have to be on. If the noise goes away when warm it’s piston slap if not it’s a rod knock.

[@davidn1562]

Awesome video at 62YO I am thinking on getting a Used Subaru, what years do you think are the better ones, Thank You

[@motorcarnut]

Thank you! It depends on what model and years as well. Here is a link that I agree with as far as models and years. getjerry.com/car-loan/best-subaru-years

[@dennikagreenland5436]

Hi my engine makes what sounds like a rod knock listening to this video however once the car is warm & driven it does get quieter but obviously doesn’t completely go away. Any advice?

[@motorcarnut]

Sounds like a piston slap. If it were a rod knock it wouldn't get better when hot. You can try a thicker engine oil and some additive and see if that helps.

[@gombalmukiyopujaanku]

Great video bro! I'm from Bali, Indonesia. I think my 2022 Mitsubishi got piston slap. Knocking for about 15 seconds. Weird, i just got 32k miles with my Mitsubishi. They recommend 0W20 oil in my country. Should i change my oil to 5W30 or thicker?

[@motorcarnut]

Thank you! Bali! You can try using thicker oil and maybe an oil additive for cold start ups, but don't go too thick or it can mess up the variable valve timing.

[@JRosepenolope]

Thank you so much! But I’m not mechanically in inclined so I’m still a little confused. I have a Toyota carolla 2022. I was 1,326 miles past my oil change. I got the car in February. I’m not sure how the past owners took care of it though. Anyway, I got an oil change the noise stopped. Was it just a piston slap? I haven’t heard it since but maybe I haven’t drove enough with it :/

[@motorcarnut]

Not piston slap but engine knock which can destroy the engine! It could of been low on oil. You have to be very careful never to let oil level go below the low mark on the dipstick. If the noise didn't come back you should be fine.

[@mikeberesford4955]

Perfect video including accent! 👍

[@motorcarnut]

Wow, thanks!

[@hendriklukana4826]

There was a knocking on my hyundia tucson 2.0 petrol but after a few minutes it was gone but it sound like it was coming from the head of the engine must i worry about it?

[@motorcarnut]

Yes, it can also be from the timing chain hitting the oil squirter, not good

[@gicugigel3790]

Thats piston slap, these are common on Hyundai's

[@motorcarnut]

@gicugigel3790 not really common on Hyundai

[@gicugigel3790]

@@motorcarnut from what i've seem, pretty common, both on diesels and gasoline engines. Their engines tend to develop piston slap or rod knock. My Hyundai engine had piston slap, replaced the engine and the new one also developed piston slap. I've seen theta 2 with piston slap and even V6. The guy from 1st comment, says his engine knocks and gets quiet when warm, thats piston slap 100%. Thats the way a piston slap acts, at least before gets worse over time and wont get quiet anymore.

[@motorcarnut]

True about the piston slap getting quiet when warms up but no so many Hyundais came my way yet with this particular problem.

[@Subieej20]

Right I do have piston slap but theres still a very faint knock when warmed up, could it be my bearing on its way out? The thing is i drive a lot and its been like this for over a year same tone didnt get worse but from inside it sounds like a diesel engine clunking knocking whatever u wanna call it.

[@motorcarnut]

It can still be excessive piston slap that does not go away and or a rod knock but it would get worse over time.

[@heykiddo2003]

My 2011 ej255 engine is shaking/vibrating a little bit on idle. Is that normal?

[@motorcarnut]

Depends, is their any other problems like a check engine like on? could also have a vacuum leak?

[@Musyaros]

i had this sound when knocking can be heard when accelerating especially at low rpm but not at idle. Any idea?

[@motorcarnut]

If it doesn't go away when hot, it's either a rod going or excessive piston slap.

[@PouyaLucky]

Thanks for explanations. a month ago picked up a 2006 WRX with 124k miles, after some day of enthusiastic driving I heard a very faint ticking noise for a few seconds, I revved slightly and the sound went away. Next morning I checked oil, and it was quite dry, I added 4 Liters Castrol 5W30 and the sound has fully gone, and the car drove normally, but I can see some oil spill on the lower plastic parts, I am scared this was a case of lemon car being masked with thicker oil with some major engine issues... Mechanic is away on sick leave and other one is booked till end of week, and I am panicking a bit.. Would appreciate some input

[@motorcarnut]

I wouldn’t drive the car until someone can see where it’s leaking from. You almost blew the engine running it low like that. Whether the person you bought it from knew or not, who knows.

[@jasonwtheis5921]

"...especially the Kia's and Hyundai's; the engines blow up, but they're nice and quiet until they blow up." 🤣 So true; my brother experienced this "feature" about 150 miles after buying a 2017 Hyundai with 120,000 miles on it.

[@motorcarnut]

That is unfortunate to hear. Hopefully, he got it under warranty. I made videos on why Hyundia's engines fail and how to get a free engine.

[@jasonwtheis5921]

@@motorcarnut No, it was a private party transaction this past summer, but I'll point him to your videos for additional research. Thanks.

[@motorcarnut]

No problem!

[@ziffification]

I get a tick that I assumed was lifter issue , it occurs a low revs and hi revs any idea why there is a sweet spot where the sound goes away ...is the con rod bearing likely?

[@motorcarnut]

That can be a collapsed lifter. Is there a misfire present?

[@ziffification]

@@motorcarnut doesnt missfire

[@motorcarnut]

Could be piston slap, connecting rod won’t go away

[@ziffification]

@@motorcarnut I am going to get it into my garage and check/set the OHC lifter gap ...what does a collapsed lifter look like?

[@motorcarnut]

@ziffification would have excessive valve lash between lifter and valve

[@Andycretin31]

I've got a tapping sound on my 2006 scion tc that starts at 2000 rpms, and disappears when I go higher. A friend said it's probably rod knock. Doesn't make any noise until 2000 rpm.

[@motorcarnut]

Very well can be that would be a symptom.

[@desperadogoingdark2847]

Is Rod knock present at start of a vehicle? Can the knock noise come and go? I have a knock that isn’t consistent and comes and goes away

[@motorcarnut]

You have probably piston slap

[@cdpc211]

Is pistol slap bad for 2014 mazda cx9?

[@motorcarnut]

Depends how bad but usually Mazdas don't really have piston slap unless engine was rebuilt poorly.

[@cdpc211]

@@motorcarnut The car knocks after the engine warms up. Do you know what causes it?

[@motorcarnut]

That’s sounds more like a rod knock not piston slap. When engine get hot oil get thinner and doesn’t cushion as well when it’s cold that why you don’t hear it when engine is cold. Also can be a weak oil pump and just a worn engine if it has a lot of miles.

[@cdpc211]

@@motorcarnut thank you

[@motorcarnut]

@cdpc211 sure no problem

[@adeladelgss8100]

Thanks for the efforts

[@motorcarnut]

My pleasure, and much appreciated

[@izstaria3409]

Theres also the tensioner knock.

[@motorcarnut]

Yes, but not like this

[@pablovillasanchez3943]

hey how are you, I have a big problem, I have a Subaru Forester 2009, I just changed the head gasket and put it back together everything, I know everything is connected but my car doesn't run, the car has a crank, but I listen the pistons hitting the heads, and I don't know waths is going on, can you help me whit this THANK YOU SO MUCH

[@motorcarnut]

Sounds like the valve timing is off. Their isn't any other way the pistons will hit the valves unless it is off.

[@barrydavison8705]

Does rod knock decrease when engine is revd like piston slap

[@motorcarnut]

No, gets worse

[@ginoasci]

My motorcycle has only 2200 miles on it and there’s an engine knock. Not a bad knock, and it’s is hard to hear at times, but there is a knocking. Considering the bike is new, could bad oil cause knocking ?

[@motorcarnut]

It could but it's usually from low oil or low oil pressure. If the motorcycle is under warranty I'd bring it in for service before any damage happened if not already.

[@ginoasci]

@@motorcarnut : it came out of service in this condition and they refuse to acknowledge the knocking. Two days ago I brought the bike in, waited an hour and a half for the engine to cool down, the general manager and the service manager both came out to listen and the said it was normal and it was the valves. It does NOT sound like the valves to me. It’s a hard metal to metal sound. The service manager says he doesn’t hear it. I say he doesn’t want to hear it. Everything I say, they just deny. I called Triumph in England and Patrick in the after sales department is as useless as tits on a bull. I’m really stuck here with this dealership and triumph not willing to help. I may have to use the news channel to solve this. They have a unit that solves problems for people.

[@motorcarnut]

@ginoasci2876 can you make a video on your channel and I can listen to it?

[@ginoasci]

@@motorcarnut : that’s a great ideas. I have quite a few but I’ll upload one that is undeniable.

[@ginoasci]

@@motorcarnut : uploaded two short videos. If you listen you can definitely hear it. Really appreciate the help.

[@eccentr3c.]

is piston slap not slapping when doing engine brake? mine when i step the gas its sounds knocking like in the video, but when i do engine brakes its gone (sorry for my bad english)

[@motorcarnut]

It's less when braking but still there, yes.

[@eccentr3c.]

@@motorcarnut ahh i see, thanks for the answer

[@motorcarnut]

No problem

[@adiljutt4332]

Hi brtoher i have bmw the same noise you said piston slap came out in it....and the oil temperature is not normal its low when i visit garage they said to me its engine rod knocking sound from down but its not sound like rod knock not even near to that sound what can i do any advice ...thanks

[@motorcarnut]

Post a video of the noise on your channel and I can give a listen

[@adiljutt4332]

Ok i will posted it soon

[@abbe6305]

@@motorcarnut kzbin.info/www/bejne/g16Um6xjZseLha8 changes main and rock bearing, stil have this.

[@motorcarnut]

That’s not a rod knock, sounds like a timing chain rattle?

[@rosendomasmanduran7000]

Que problema tenia ese motor ?? Donde estaba el problema

[@motorcarnut]

This was a demonstration. The engine with the rod knock needs to be replaced or rebuilt. The piston slap doesn’t require anything unless it doesn’t go away when fully warmed up.

[@VeeTwelve202]

Hi. If it’s a rod knock. How long do I have before engine is defective?

[@motorcarnut]

Immediately

[@VeeTwelve202]

@@motorcarnut the knock comes and go away. Sometimes I idle and I don’t hear it at all. At time at hear it. Also slight hesitation when starting. Thanks for your reply.

[@motorcarnut]

You can’t play around with engine knock it will destroy engine without any more warning signs

[@maegantucker973]

Mine did that on my Corolla. I can’t drive my Corolla anymore. Lol.

[@motorcarnut]

@maegantucker973 nope

[@ianwillmott3408]

Mine is odd its got a new rebuilt engine its quiet when cold then when it warms up it has a small knocking noise but only at idle if u give it any kind of throttle it goes quiet again

[@motorcarnut]

Normal

[@getmotivatedfishin410]

Mine (04 Yukon )sounded just like that my starter went out just replaced it today when to boost the battery crank revved it a bit and I heard crackling noises and the engine died ! 😭

[@motorcarnut]

Sounds like it just seized up

[@kenpen21]

My Subaru sounds like the second one when it starts up and is very loud, however after it warms up it sounds pretty normal 95% reduction, I can hear a little when I give it higher Rpm’s but with windows up can’t hear a thing. Would this still be piston slap since it goes away when warm?

[@motorcarnut]

Yes it would

[@captivabreed176]

It’s likely what your hearing is your valves ticking. This is also very common with Subarus

[@alexreynolds99]

Can I send you a video of my 2014 Tribeca?

[@motorcarnut]

Sure, just post it on your KZbin and let me know!

[@Zigggy87]

Hi is both cars cold start up

[@motorcarnut]

Yes

[@Zigggy87]

@@motorcarnut hi is ther any way I can send videos direct to u for advise

[@motorcarnut]

Post on your channel and I will watch it

[@Zigggy87]

@Motorcarnut ok Thank's

[@motorcarnut]

@Zigggy87 no problem

[@2ebba]

I have a knock on 3000rpm only sti 2004 with a lot of power loss but no knock whn idle any idea ?

[@motorcarnut]

Sounds like pistons are failing

[@anthonypowell3854]

What’s worse to have. And is piston slap something you have to address right away.

[@motorcarnut]

Engine knock is much worse. Piston slap that goes away when vehicle is hot can last the lifetime of the vehicle. Piston slap that doesn't go away after warm should be addressed sooner than later.

[@gotfinals]

Does a quiet slight knock mean you need a new engine?

[@motorcarnut]

On a Subaru probably not

[@GHOSTERING]

Depend, if you have rod knock but you stop the engine soon enough you can just rebuild the internal and the engine will be good for a long time, sometime the block have no damage and can be save. It just cost a rebuild wich is cheaper than buying a brand new engine.

[@ruebyzilla3314]

Gra ta ta ta ta ta compared too GRATATATATATATATA i think I get you 😅

[@motorcarnut]

Hopefully :)

[@Aashishkebab]

If the knocking is quieter, is it not rod knock? I've had my engine go low on oil (dipstick completely dry) a few times. But it's fairly quiet and only occurs at around 1,500 RPM.

[@motorcarnut]

Unfortunately it can still be a rod knock just not the bad yet.

[@shawntee1859]

It’s Definetly a big end gone (connecting rod bearing) engine is toast. Replace itl just get worse.

[@Aashishkebab]

@@shawntee1859 fear-mongering for no reason. Chill out.

[@universaltalents28]

how much to fix either or?

[@motorcarnut]

Can’t give an estimate too many variables

[@universaltalents28]

@@motorcarnut rough one neither guesstamate lol

[@motorcarnut]

@universaltalents28 $1500 to $4000

[@weazymholla]

thanks brother i thought it was knock 😂😫

[@motorcarnut]

No problem 👍 Glad it helped!

[@hongccc]

Nice video ! Will Piston Slap / Rod Knock make your car shaking a bit? Are there more hints that can help distinguishing them?

[@motorcarnut]

Yes it will. Piston slap is twice as fast as rod knock

[@hongccc]

​@@motorcarnut You are so helpful! What do you think about this noise? Planning to do a full check later this year, and i hope this is not some serious problem kzbin.infob-_rA-0jx3M

[@KorayRuthlessvillian]

Is piston slap for a few seconds on cold start normal?

[@motorcarnut]

According to Subaru, yes

[@Subie_OffXroad]

What happens when you accelerate or push the gas pedal with a rod knock??

[@calebcoyle532]

4:24 I thought you said Hondas blow up especially for a sec I was concerned

[@motorcarnut]

Hyundai

[@joshbarnhart6254]

Does a rod knock mean engine replacement ?

[@motorcarnut]

Short answer, yes but also can be rebuilt

[@pawlarsen7815]

Im kinda confused, got a Peugeot 206 below 2500 rpm not that much sound, well it ticks, but around 2500 and above cold or hot it slaps like crazy, only under load, if i put my foot on the clutch i can feel vibrations and if i take my foot off the gas there is nothing!? Upon startup it can make a clonk sound and also sometimes when i change gears fast when it's cold. Any thoughts of what it might could be?

[@motorcarnut]

Hard to tell without hearing it, maybe you can make a video and I’ll give a listen

[@syedgilani7108]

excellent video

[@motorcarnut]

Thank you very much!

[@lakotaholloway6408]

Could I send you a video of my vehicle some how to see what it is I can’t tell

[@motorcarnut]

Yes, post it on your channel and let me know

[@TurboWolf88]

Alright now stuntman hold her to the boards and get to it! LOL

[@benzlover55]

What's it got, STUNNT MAAAAN!

[@Jacob-xe2si]

“You could hear it from another state away🤣”

[@motorcarnut]

Yep, some of them are noisy when cold.

[@tanweerahmed6861]

hi great video , piston slap is gradual or just suddenly starts one day ? thanks

[@motorcarnut]

Piston slap is gradual as it starts to wear.

[@dogkamusica5961]

Tengo un Subaru Impreza sport 2017, es normal que cuando lo encienda este acelerado y luego se normalize?

[@motorcarnut]

When you first start it, it is normal for rpms to raise a little if it’s too much the throttle body may need to be cleaned. I have a video on that too

[@NguyenPhucPlaylist]

Sounds be like that, but everything works normal, right?

[@motorcarnut]

Most of the time, yes

[@vanhasydan4754]

With rod knock, engine speed with changes the rate but not the intensity.

[@motorcarnut]

Depends on the severity of the knock.

[@Charr9TV]

I have a video on my page can you tell me if it’s a piston or rod knock

[@motorcarnut]

I just did. That definitely sounds like a rod knock. One thing you can do to rule out an accessory or pulley noise is to take off the serpentine belt and start it back up, if it sounds eacly the same its a rod knock and would have to be rebuilt or replaced.

[@jibzz4749]

That sounds a bit loud, my Subaru never knocks that loud, only has a bit of injector noise at idle

[@motorcarnut]

This is a comparison between an engine knock and piston slap, yours is not supposed to sound like either one unless there is a problem.

[@Andy3x]

I dont have a subaru anymore but i have an 02 accord im trying to flip, upon start it makes a knocking type sound but only on cold starts. After 10-30 secs it goes away and the car drive normally shifts smooth and makes no sound. Is it bc it’s basically oil starved on cold start and as oil circulates it goes away?

[@motorcarnut]

It very well can be. If you didn't already, try changing the oil and filter and using a oil additive like STP, should help.

[@Andy3x]

@@motorcarnut i did an oil change and the time it takes for the noise to go away is way shorter than before the oil change, im gonna try stp and see if it stops it completely

[@motorcarnut]

@Andy3x yes, it’s cheap and worth a shot.

[@MrSpandexy]

And a 10x1.25 nut

[@motorcarnut]

Thank you again!

[@daniellaschockaert6046]

What’s an easy way to get rid of a engine rod knock?

[@motorcarnut]

No easy way outside of rebuilding the engine.

[@joeyhdz3435]

Yep, I always have loved an engine that will blow up very quietly😆👌

[@motorcarnut]

Depends, engine knock, yes but piston slap could go on for years on Subarus with not problems.

[@wicked5312]

I must have a bad ear on this stuff it sounds like my truck but my sound is constant and follows rpms i have a short clip on my channel

[@motorcarnut]

I’ll give a listen when I’m on my desktop.

[@wicked5312]

@@motorcarnut i'd appreciate that

[@sporty1976s]

What if the rod knock goes away?

[@motorcarnut]

You’re very lucky

[@sporty1976s]

@@motorcarnut I used the wooden dowl rod method to listen to the inside of the motor. And it was clattering loud. The tensioner pulley started making a noise and the power steering went out the ps pulley started screeching and the knock went away at the exact same time. I changed the tensioner pulley and power steering pump (I used the original pulley) and the vehicle runs great. So I'm actually thinking it was the ps pump that went out causing the pulley to screech and knock.

[@motorcarnut]

Great diagnosis! That was probably it!

[@xom.]

Thats the subaru swag

[@motorcarnut]

Yep

[@alihasan-dg7vz]

Just happened to my car 10 days ago

[@motorcarnut]

Sorry to hear that, maybe it can be rebuilt or replaced?

[@alihasan-dg7vz]

@@motorcarnut I must change the engine or I will sell the car

[@motorcarnut]

@alihasan-dg7vz Yes, but first get a second opinion from someone local

[@Niismex]

Washing machine vs helicopter

[@motorcarnut]

I guess, lol

[@zeekflash6924]

Anyway to fix , either or both .. with engine additives .. engine restore

[@motorcarnut]

Unfortunately no.

[@jtmartin8445]

That’s garbage my 4.2l ford with 300k miles on it sounds quiet as a Prius compared to this thing. I’d be scared to drive that pos around the block both of them sound like the pistons are about to shatter from all the slack and vibrations. Really sounds more like a wrist pin knock instead of piston slap.

[@motorcarnut]

You never owned a Subaru.

[@bluegizmo1983]

... am I the only one who couldn't hear a difference? The piston slap and the rod knock sounded exactly the same

[@motorcarnut]

Must be, because they are not the same. Piston slap is a loud faster tap, rod knock you can hear from down the block

[@justanothermotorizedbikech]

Use headphones

[@drdab_]

Slap is solid a knock sounds like drumsticks on a metal trash can lid

[@Josh-sm8mj]

Im definitely the second car 😢

[@motorcarnut]

??

[@cromwellco]

Sounds like diesel clatter

[@motorcarnut]

Yes it does.

[@izstaria3409]

Mine is slower.

[@motorcarnut]

Can be a valve tick then

[@josephhobbs6213]

I have a 03 Kia rio. Before timing belt popped and I ruined the head there was to ticking. Now I have used head and new timing components and I have a clicking or ticking noise. My question is how can I tell the difference between knock, slap or valve tappets. I’d like to think mine are the valves. It’s not loud at idle but gets slightly louder with higher rpm and it’s rhythmic

[@izstaria3409]

@@motorcarnut it's slow but stops when warmed up. Like a beat sound. Slap, slap, slap .doesn't sound anything like videos of piston slap. I can't find the sound anywhere on KZbin

[@motorcarnut]

Timing chain tensioners too make that noise and common failure on Subarus.

[@nichtgutefursienimmer7888]

Hello, great video. Here is what I got. The noise goes away only when idling or at stop sign, sometimes it just goes away: kzbin.info2VhEvk3qpn0?si=lmFE8hihEfsYvPL7 I listed the details in the description along the the check engine codes. What should I do? Thank!

[@motorcarnut]

Link doesn't work, try posting on your channel.

[@gotsu21]

​@@motorcarnut here it is under "shorts"

[@gotsu21]

​@@motorcarnutor could it be the failing timing belt tensioner?

[@motorcarnut]

@@gotsu21 Ok, just heard it. You should of reved the engine so I can hear when it goes away, if your engine has a timing belt if could be the belt tensioner if not it sounds like a rod knock.

[@gotsu21]

@@motorcarnut Hello, I uploaded three videos: 1. Cold Start - Idle - Rev 2. Cold Start - Idle - Drive - Rev - Idle 3. Warmed Idle - Rev (Sounds like a diesel engine). But there are chorus of Clanking sounds, it appears. The engine has a timing chain instead of a timing belt. Since the check engine light on (P000B, P000C, P0014), it intermittently has sluggish acceleration, and the Clanking at idling comes and goes. What do you see? Does the car need some nail service or spa treatment? Thanks for your great videos.

[@nicholebaker8085]

My car is doing this and just cut off ‘

[@motorcarnut]

Have it checked out asap hopefully you didn’t blow the engine.

[@nicholebaker8085]

@@motorcarnut unfortunately I did 😭 have to get a new motor

[@motorcarnut]

Sorry to hear that