MX5 NA Miata - How to replace your thermostat (cooling problem fix)

In this video I'm going to fix a cooling problem because my Miata is not heating up properly. The car reaches operation temperature just fine but when I start driving the temperature drops, especially at high speeds. When an engine gets below operating temperature the thermostat will restrict the flow of coolant so the engine stays at operating temperature. In my case the temperature keeps dropping so I think that the thermostat is not closing properly. That is why I'm going to replace it with a new one!
A big discussion is which coolant is the best for your Miata and there are so many conflicting answers so I encourage you to do your own research and draw your own conclusion what’s best for your car. It also depends on where you live and how you use your car.
MiataMods Vlog #8 - MaX5 Cup races #1 on Circuit Park Zandvoort:
» • MiataMods Vlog #8 - Ma...
MX5 NA Miata - How to perform a coolant flush:
» • MX5 NA Miata - How to ...
Things you will need:
» Wheel blocks
» Jack
» Jack stands
» Spare wheels (optional)
» Drain pan or bucket
» Phillips head screwdriver
» Gloves (optional)
» Pliers
» Heat gun (optional)
» Penetrating oil
» Socket wrench
» Socket extension (optional)
» 12mm socket
» 10mm socket (if you want to remove the overflow reservoir)
» Pan with boiling water (optional)
» Paper towels
» Scraper (dull razor blade or old credit card)
» Vacuum cleaner (optional)
» Brake cleaner
» Thermostat & gasket (goo.gl/22ADyM)
» Torque wrench set to 17 lbf-ft / 23 Nm (optional)
» 6 liter or 6.3 quarts of coolant / antifreeze (goo.gl/5f3ICu)
» Funnel
» Soda bottle (optional)
» Old jugs (optional)
Music I used:
» Ryan Little - Damage ( • Ryan Little - Damage [... )
Follow me:
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» Facebook: / miatamods
» Twitter: / miatamods
» Google+: plus.google.co...
★ If you liked this video please like and subscribe guys! ★

[@loveableterror]

Dude, I absolutely love your videos, they are so matter of fact, you a little bit of commentary, but you go step by step. It's so perfect, thank you for what you do!

[@MiataMods]

Thanks man! 👍

[@harpermarley5217]

A trick : watch series on flixzone. Me and my gf have been using it for watching loads of movies lately.

[@juniorjaxon4517]

@Harper Marley Definitely, I've been using flixzone} for years myself :D

[@alex1591988]

Hi, great video, as always! Fun fact, on the Miata and a lot of other Mazdas, you don't need to turn the heat on, the water always circulates via the heater core. So for people doing this in the summer, it'll be more convenient, especially if you're going to drive the car around to heat it up.

[@MiataMods]

Thanks for letting me know!

[@Glitchmaster767]

My Miata was having the same sort of issue where it would stay "cold" no matter how long I was driving for Thanks to your video I diagnosed and fixed the problem and now everything is normal! My heater works again too.

[@cadensteffensmeier5116]

Good video. You don’t need to drain your radiator completely. Take the cap off and pull the plug. Watch for the fluid to drop just below cooling channels, than put the plug back in. Also you don’t need to take the hose off, just take the housing off with the hose. 2 things, you don’t need to bleed it a lot as little fluid drained out and 2 less work. I can do my thermostat in under 10 mins this way. Other than that. Good video

[@MiataMods]

Thanks for sharing your tips Caden!

[@Teknakill]

This is a COOOOOOOOOL video. Quick tip, always keep the rad cap loose on the radiator (when doing the job) so nothing falls into it by accident, that can also be done for the oil cap when doing oil changes. Same principal applys for simular jobs. If not the cap, then just put something over the holes to be safe, like a towel. Don't forget to bring a towel. 😂

[@MiataMods]

That's a great tip, thanks for sharing!

[@CrogDogsGarage]

Silver lining.....You're not sunburnt, you're color matched!

[@MiataMods]

That's genius hahaha, thanks 😂

[@bostinaycock8316]

yo dude thanks for making this vid. the production quality is really good.

[@MiataMods]

Thanks for the kind words dude!

[@mysterytour5983]

I am learning a lot at looking your videos, you talk at the right speed and clear! So far I did many thing on my car and i am far to be a mecanic and people are impressed of what I done! Maybe because i am a girl! lol -My moto is if some else can do it why not me!😂

[@MiataMods]

Props for you trying to fix stuff on your own!

[@BecauseMiata]

Great instructions; very thorough. As soon as I finished watching your video, I got a check engine light on my BMW - failed thermostat! How ironic, right? Lol. It's under warranty, so no worries. Looking forward to your next video on coolant flushing. I'm past due 😫

[@MiataMods]

I wish the Miata had a check engine light for that.. had to do some research before I found out it was my thermostat.. Anyway, my new 'track day' vlog will be online upcoming Friday and next Friday the coolant flush! Thanks for watching! 👍

[@frankraymond4627]

My gauge always read to the cold side of the middle of the range. And I never heard the fan come on, so I thought the thermostat was failed. So, I replaced it tonight. Turns out, the gauge still reads slightly to the cold side. I guess that's just one of my car's quirks. Thanks for the video tutorial

[@colin_g]

Miatas read at around 11 oclock (or 11:15 if youre being picky), so don't worry it's normal!

[@JOROM90]

One of the best instructional videos I've watched. Subscribed!

[@MiataMods]

Thanks for the compliment man!

[@Bbeavis]

Neat tip regarding the rad cap sitting next to the hood latch :P

[@MiataMods]

Thanks! I do the same with my oil cap!

[@jjtc6]

Just picked up a eunos and on my 200km journey home the coolant temp needle never moved off cold unless i was sat in traffic so i'm hoping it's as simple fix as this! It was minus 1 degrees and snowing today so that makes it worse I guess! Awesome video, love the troll face. Hi from the UK :)

[@MiataMods]

Sounds like the same problem! Don’t wait too long with replacing the thermostat! Running cold for long periods of time is not good for the engine. Congrats on getting a eunos btw mate!

[@jjtc6]

In the garage until April, roads are so salty and wet here I don't want to let her out till there! Will do the job asap though. Thanks!

[@JonPaulovkin]

Just an FYI to anyone else out there who gets confused about this like I did: I discovered that the 1.6L and 1.8L engines have different thermostat housings. The 1.6L has a vertically-mounted thermostat housing, like the one in this video. (hopefully MiataMods can confirm that his car is a 1.6L). The 1.8L engines have a horizontally-mounted thermostat housing and are shaped slightly different

[@MiataMods]

I hereby confirm I have the slowest of the two; the 1.6.

[@01Jelen10]

Perfect videos with proper instructions, thank you!

[@MiataMods]

Thanks man, glad my video was helpful!

[@karson1214]

Well... Mine gets too hot too easily. It gets to 3/4 of the water temperature gauge after a medium range drive for about 20 or so minutes and a little longer than that it gets to the H mark and it stresses me out every time... The gearbox also has some problems when the car has been driving a while, I have difficulty in engaging into any gear even the first gear. The transmission tunnel is pretty warm when this happens and I can feel the heat through the carpeting. I really hope these problems can be settled soon..

[@MiataMods]

Did you already change the thermostat? And about the gearbox, I would replace the gearbox oil and do a shifter rebuild

[@karson1214]

Thanks for your advice man! Sorry for not responding earlier, I believe the temperature problem is fixed and yes by replacing the thermostat. As for the gearbox, the master and slave cylinders were replaced and now it works perfectly fine. The air filter has also been changed to a high flow K&N one. It currently feels a bit more punchy but still a bit sluggish.. it doesn't seem to have enough power to go up relatively steeper slopes like the ones in parking garages,but is this like a common problem for miatas or is it just mine though?

[@MiataMods]

Could be a common problem, they do not have a lot of torque

[@eckard9597]

@@MiataMods i don't seem to have any issues going up steep hills, there isn't much torque but it doesn't seem to cause any issues on a hill for me unless i'm trying to pull away after a red

[@MateusBald]

Your editing skill is amazing +sub

[@MiataMods]

Thanks for the compliment man!

[@frankraymond4627]

Nice work as always. My only comment is that I would have replaced the upper radiator hose at a minimum. It's easy, cheap insurance and you had the system drained anyway. Your vid almost makes me want to do mine.....almost. :)

[@MiataMods]

Thanks Frank! It's a good idea to check the hose but it was fine and at some point I want to replace all the hoses with a set so I didn't bother swapping this one. Thanks for the tip tho! 👍

[@unified95]

So you're not using any seal promoter like any paste or seal/silicone etc? I need to do it on mine as the gasket has a small leak. Also, I really don't want to remove all the coolant, I guess it should work with draining just enough so its below the thermostat level.

[@MiataMods]

No need for any seal / sillicone! I've done this a lot of times and the gasket was always sufficient. If you don't want to waste coolant, I would suggest using a large bucket to catch all the coolant so you can re-use the coolant later. To remove the coolant partially feels like a lot of hassle so I would remove the coolant completely and add it later

[@JamieBainbridge]

You definitely need a new radiator. The green/brown colour of the tanks indicates the plastic is degraded. Soon the plastic will craze with internal cracks, then the radiator will leak or explode one day. The only correct colour for the tanks is black.

[@MiataMods]

You are correct! However, I made this video 7 years ago and I still have the same radiator so it's still fine after all those years haha! But it's an accident waiting to happen so yeah, I need to replace it eventually

[@JamieBainbridge]

@@MiataMods Mine was the same. People say theirs explodes and you have about the time it takes to pull over before the engine is dry without coolant. I got an upgraded core with original style tanks. I couldn't get an aluminium radiator to fit with the big NA6 aircon fan.

[@DanWebster]

This is a great video. Paw Paw subbed

[@MiataMods]

Thanks Dan!

[@moeriou8431]

I don't have a heat gun but could I use the hair dryer I keep in my car?

[@MiataMods]

Haha sure man, that always works! 🤣

[@qizhou6106]

Nice job!! got a question: my miata temp needle just a little past the halfway. do you know how the problem comes? cheers, hope for your answer!

[@MiataMods]

This is a common problem and it has something to do with the sensor or the gauge itself. Don't worry, your engine is not overheating or anything, it's fine! You can replace those but it's a lot of work for something that is not really a problem.. it could not hurt to change your thermostat tho! Not a lot of work and the parts are cheap!

[@qizhou6106]

MiataMods thanks bro! Hope to see your updates

[@broganhogan3469]

Great video, dumb question. Can I use blue gasket sealer/solvent on the housing in the place of a paper gasket?

[@MiataMods]

Not a dumb question at all! You could, but I would not recommend it because it can get mixed with your coolant and you don’t want pieces of liquid gasket going through your cooling system. You’re better of spending a couple of bucks on the OEM paper gasket

[@broganhogan3469]

Thanks kindly. I changed the tstat a few days ago and did grab the $1.51 gasket. Good call!! No leaks!! Keep up the great vids

[@L0STGVRVGE]

I have sort of the same issue but for me it goes as low to the C and would stay there for a while then get back to normal and repeats sometimes bouncing for a few seconds I’m going to try this hopefully some luck I own a 97’ 37800 miles and knowing the owner they didn’t replace anything and left the car sitting for years

[@MiataMods]

That's definitely the thermostat. Don't use the car while it's doing that, it can really hurt the engine running that cold. Do a coolant flush while your at it, I've made a how-to video about that as well.

[@dgcmusi]

Great tutorial my friend..great job...thank you 🙏

[@MiataMods]

Sure no problem! 👍

[@joro8604]

Any loctite or anti-seize needed for cover bolts? Good vid.

[@MiataMods]

Thanks! Nope, that’s not necessary

[@kennethjueves698]

Hey man!! Quick question, does it matter which part of the OEM paper gasket is pointing up? Like does it matter which side is up?

[@MiataMods]

Nope it doesn't matter 👍

[@nolahahnshouse3389]

showing me new shit all the time bro! crazy as it sounds.. can't wait for my car to over heat so I can try this! thank you again for stickers bro! can't wait to see them on rwby!

[@MiataMods]

Haha no problem bro, thanks for watching!

[@NunoFariaBMX]

I was looking for a new thermostat for my 91 NA6 and found out there were two different types, 88ºC and 82ºC, which one do you use? Thanks a lot, really like your videos.

[@MiataMods]

I would recommend the 'hotter' one (88 degree celsius or 190 degree fahrenheit) but there isn't a huge difference so if your local hardware store only sells the 82 degree celsius one, that's fine too.

[@NunoFariaBMX]

Thanks!! Do you recomend the OEM one or any aftermarket will work fine?

[@MiataMods]

I would go for the OEM one just to be sure

[@EddieH711]

Hey thanks for making this video. I have been having issues with the radiator fan not kicking in. I notice that the cooling fan relay in fuse box (engine passenger side) has the part # LA 10 relay which is 10 amps? The manual indicates 30 amps. I’ve been looking to replace the relay but could not find a 30 amp relay for the cooling fan. Is the LA 10 the correct part.? It does fit the pins but I’m confuse as to why it’s only 10 amps?

[@jimd1617]

your vids are so helpful! :)

[@MiataMods]

Thanks 👍

[@jakeguitarbass7209]

Another great video from Miata mods !! Question: How long does it usually take for the thermostat to kick in while running the engine ? Because I once had trouble with mine and it over heated because I didn’t put enough coolent in.

[@MiataMods]

That depends on various factors like the outside temperature and how hard you are driving but I would say 10 minutes? You just need to watch the temperature gauge closely and you’ll be fine

[@jakeguitarbass7209]

MiataMods I see. Because once I had an issue when changing my coolent... and when I was on the freeway it went hot straight away because I didn’t know mine had a thermostat. So basically the engine cooling system was completely dry empty. And didn’t have enough coolent for the whole system.

[@ThatBlueXT]

Is it necessary to drain your coolant only installed a new radiator afew weeks ago but I'm about to tackle my thermostat and I dont really want to design out fresh coolant and burp it all again thanks in advance

[@slingbart705]

I see the old Gasket ws metal but the new one is paper, any issues with that? Paper gaskets were always on the old skool Iron block engines but aluminum....

[@MiataMods]

Nope no issues!

[@dgcmusi]

MiataMods so no silicone on the gasket for a better seal...not needed ?

[@pomaib4043]

My car is over heating not under heating, do i still need to change out the thermostat?

[@MiataMods]

Yes, changing out the thermostat is one of the easiest and cheapest things you can do to diagnose the problem so start with that.

[@carlywayss9087]

Do I really have to drain all the coolant or can I just take off the top radiator hose and wing it?

[@MiataMods]

Yeah you could try it, wouldn't recommend it tho 😆

[@dcdad556]

A little help... housing bolts: left one is short; right one is a little longer. What are their metric sizes? Mine are corroded. Thanks, everyone!

[@MiataMods]

Sorry, I don't know their metric sizes. Google is your friend!

[@TheBishop12]

What brand of funnel is that? looks like it hugs the opening tighly so no air gets in. Thinking about getting those EP Auto spillproof funnel kits with screw on adapters but they cost like $25+

[@MiataMods]

It’s just a cheap funnel from the local hardware store, nothing fancy. A normal funnel will work just fine mate

[@TheBishop12]

MiataMods Noted. thx kindly for your response !

[@GrimmWarrior19]

Having the exact same issue on my 95 but replaced the thermostat not long ago, going to go through it again soon. Question though. When your temp gauge reaches "C", does your Miata downshift or rev high?

[@MiataMods]

Hey man, yeah that's normal! Not like 3k rpm but it's around 1400 rpm when it's a cold start. Goes down pretty quick below 1k tho.

[@GrimmWarrior19]

I mean as you are accelerating or "at speed". I'll be driving down the highway and as soon as the gauge drops that low, it's as if my trans loses a gear. If I allow the car to "reheat" after stopping I'll get it back, this just repeats and I don't want to cause damage, if anything could happen.

[@MiataMods]

I've never had that problem and I've never heard of it either, but it sounds pretty serious dude. Check your thermostat again because that should block the flow of coolant and keep your engine at operating temperature. You got an automatic gearbox?

[@GrimmWarrior19]

Yeah I sure do.

[@MiataMods]

Ah ok. I don't have any experience with that, we all drive stick in my country. Start with your thermostat, maybe throw it in boiling water and check if it's working properly.

[@thomasheaberlin3220]

Do you need to use any gasket sealer like you would when you replace a valve cover gasket?

[@MiataMods]

Nope, just make sure you buy a proper OEM gasket

[@itzkoi9568]

My car is overheating when I’m stuck in traffic but fine when driving fast, could this be a thermostat issue too ??

[@MiataMods]

For sure! If not I would suggest replacing your radiator and the radiator hoses!

[@mabi6819]

Hey, did you get a paper gasket with the thermostat? Reason I ask is, I just purchased a thermostat which had the black rubber o-ring on it but did not include any usual paper gasket. Also, when I install the thermostat this way, the housing is not closed together due to the rubber being too fat. Any ideas?

[@daazn9iant1]

In the video, he removed that black rubber o-ring. You'll need to buy a paper gasket.

[@MiataMods]

Exactly, remove the rubber and buy a OEM paper gasket

[@pete5534]

Nice work.

[@fabioparis1348]

Lol i dont have a miata but i am watching any way keeping up with ma dutch bro's

[@MiataMods]

Haha Miata love transcends ownership! Are you a fellow dutchman?

[@fabioparis1348]

MiataMods yes i am 😌

[@MiataMods]

Send me a message on Instagram or Facebook bro!

[@fabianhcarsnvlogs]

My mates mx5 has a problem with getting hot, so i think he may have come to see this video to get a reference

[@MiataMods]

I think so too 😛

[@nbmiata8401]

Ga je nog een coolant reroute filmpje doen?

[@MiataMods]

Uiteindelijk wel, maar ik heb nu eerst andere projecten op de planning staan!

[@Chimera6297]

damn if you took the video one mile before, you would've had 181818 on the odometer missed opprotunity... also I used gasket sealer, I don't trust that gasket with my life

[@MiataMods]

Goddammit you're right! You're not right about that gasket sealer. The paper gasket is perfectly fine and you don't need to use gaskey sealer. The trick is to buy the OEM gasket, not some cheap knock-off

[@patriciazamora4318]

Great video! Thanks for sharing your knowledge! Question: to ensure no leaks, is the use of gasket silicone recommended as well? What are your thoughts? #MiataGrl69

[@MiataMods]

No this is not recommended, the standard gasket should be sufficient. If not you've installed the housing incorrect or you did not use the right amount of torque on the bolts.

[@FriedTurkey]

Ha hey. 7:42 Got those pliers too.

[@goreobsessed2308]

Don't loose your drain plug those things can be hard to get lol

[@MiataMods]

Well you can loosen it, just don't lose it ;-)

[@frankbouwman8507]

Goed gedaan Jongen!

[@angelmx5734]

Did he just add distilled water only???

[@MiataMods]

Yes I did 🤷‍♂️

[@dandillon5163]

Sorry but you’re going to need a radiator replacement. Look at the color of radiator it’s ready for replacement.

[@MiataMods]

Yeah, but then again, I made this video 4 years ago and I’m still running the same radiator soooo 😅

[@dandillon5163]

@@MiataMods Your so lucky. It didn’t work that well for me.

[@MiataMods]

I will eventually run out of luck so I really need to replace it.. would be a nice video tho

[@Tennesseeroadster222]

@miatamods is the music yours

[@MiataMods]

No it’s not. Credits are in the video description

[@fastbicyclerider7300]

do you live in nederlands

[@MiataMods]

Yes I do! 🇳🇱

[@fastbicyclerider7300]

Ik ook

[@JodBronson]

If you live in " Warm Climate " aka ... California, Arizona, Texas, Florida etc.... By Pass it and call it the day. The Engine runs Cooler and Average Temp on Ours was -40F after By-Pass. I just did a Video that took me about a Week to gather the Data / Heat: Here is the Test and the Results of the Thermostat By-Pass : kzbin.info/www/bejne/nJi4iptshbuJoJI

[@MiataMods]

Personally I would not recommend removing the thermostat. It's there for a reason and your engine should never overheat, even if you live in a 'warm climate'. If it does, something else is causing the problem. I know a couple of Miata owners in Arizona and Texas and they never have any problems with overheating. Doing a flush, using a different kind of coolant or replacing the radiator are common solutions to overheating problems.

[@goreobsessed2308]

Your not wrong but it's a 7 dollars part might as well fix it

[@chamwow168]

Is it just me or is watching someone struggle with a stuck hose very hard to watch?

[@MiataMods]

It's not just you, we all love to watch a guy wrestle with a long big black hose

[@Misfits89]

animals will drink it and DIE... lol

[@MiataMods]

They will, so be careful

[@dgcmusi]

THE CURE it’s very true

[@ryankribs9923]

We just gonna ignore the fact that he was going 100

[@spencermartin1131]

K/PH, not M/PH