Engine Vapor Lock and How We Deal With It

[@farmthestars3962]

This is the best explanation of this ive ever seen. I actually understand what is going on here. Thank you.

[@bobwolff68]

Dude - really great explanations. I've watched several videos and none of them were terrible, but yours is the best explanation holistically. Thanks!

[@kayeninetwo3585]

Very, very informative. Many people with older or classic cars have encountered vapor lock, but few understand the phenomenon. This was really help for me. Surprisingly, hardly any of the classic cars I've owned in the last 20 years have had the problem. I just put a new fuel pump on an early '60's car I own, however, and had a problem with the fuel system. Don't know if I changed something that resulted in a vapor lock situation. At first I thought the the new pump was bad, but it started up again today fine. I'm still investigating.

[@johnmiller-in5bt]

You need a return line from your fuel tank to the fuel line by your carburetor. If you have a by pass fuel regulator . The bypass line from fuel pressure regulator goes to the return line that goes to your gas tank That allows the hot fuel to travel to your tank and back again .cooling the gas . prevents.the.vapor lock. If.you.think.you have vapor lock. Go to your gas tank.and listen.you should hear the fuel boiling in there Also if.you pull your gas cap off sometimes there will be pressure that comes out taking cap off.

[@ThePeanutization]

Thank you. After like 3 years I finally solved the vapor lock problem of my 1982 car. I was having some trouble finding one of those filter with vapor separator here in our place, but then I realized, that my carb has some sort of outlet, just right after the float valve. It's somewhat restricted, and is the highest point of the fuel system, it was plugged close before, then now I tried to hook it up to the fuel return line, and there goes vapor lock goodbye. =)

[@thepenitent3633]

i see thanks for your reply

[@NeoJ4K3]

I really appreciate your content. Owning the last AMC developed jeep, I appreciate videos like this. Hope all is well and, as always, can't wait for what content you may have in store

[@paulsthormes251]

Thanks for sharing I just installed one made a big difference no more vapor lock.👌

[@Darkipod]

I wish I could find one of these near me, super neat car! Love you videos!

[@slicksnewonenow]

Another ancient Hillbilly trick that we used to employ, was clamping wooden clothes pins on the fuel lines about every foot or so... they work as heat sinks. I grew up in Houston and some Old-timer taught me that trick. Worked pretty good when the temperature was up above 90...

[@BeanieandCecil]

I don't understand how that could work as wood is a horrible heat sink. Metal is good but not wood. Wood is actually an insulator.

[@regpeeler5509]

Oh!! Can you provide the part number to the evaporator filter?

[@johnbridges9264]

WIX 33040 or you could use WIX 33041

[@kikoramirez6803]

thank you for your video NO MORE VAPER LOCK 65 el camino back on the road up grade from a 230 to a 327 .

[@8avexp]

I recognize that AMC dash. My '78 Gremlin had that same instrument cluster.

[@speedrover]

Excellent explanation!!

[@jverrelli1]

Very good explanation, you sound like a professor

[@bernielomax4702]

We had a lot of fun tonight. But there’s nothing funny about vapor lock.

[@Fentertainment]

I have a 85 c10. Removed the 4.3 with quadrajet for a sbc 350. Added a electric fuel pump and the return to the tank is at the regulator on the side of the frame rail beside the engine. Starts easy cold, Hard start after its warmed up, ran and cut off like you explained. Thinking of capping the regulator return port, then running that return line up next the carburetor and adding this filter. The hard start when warm is the only problem I have. I wonder if I could remove the holley electric pump and regulator and add a mechanical pump back in the system to quiet it down? Thank you for this video!

[@AmericaFirstKorey]

I would run a mechanical fuel pump and a Wix 33040 (5/16" intlet-outlet) or 33041(3/8" inlet-outlet) fuel filter with the vapor return port. Also, don't forget to install a heat shield under the carburetor - very cheap insurance to keep the fuel bowls cool. Check out OER Part # 3969835 which is a GM Reproduction. Make sure your fuel cell or factory tank is well vented.

[@sweaspurdoddd5466]

0:47 sounds like me frying some fries at 02:30 at night

[@paneerpolice3454]

I have maruti suzuki wagonr LXI CNG which has a petrol engine with factory fitted CNG gas as alternate fuel. Once my father was waiting at a carwash in hot afternoon and suddenly car was not turning on. Later he opened fuel cap of petrol tank he heard a hiss. Then after 3 cranks car started on cng fuel automatically. Normally our car starts on petrol then gets transferred to cng after 20 seconds

[@ecesarchavez]

Great video and perfect for me since it’s similar to an AMC 360

[@ramjet4025]

Great, wonderful sound

[@InternetDude]

My Eagle tank has a ton of pressure when I remove the cap, is that normal? One of the rubber lines looks kinked coming out the sending unit. It starts & runs fine though.

[@CelGenStudios]

Make sure your vent line between the tank and the charcoal canister is not blocked. There's a restrictor in the vent line so it will pressurize like that but should equalize after 15-20 minutes being parked.

[@InternetDude]

Update: the gas tank vent line at the top of the tank was plugged, I blew it out with compressed air and that fixed this issue. I think there was a little piece of rust in it.

[@hailtothe_rooster1572]

My pump has a return line already but still dealing with vapor lock. Do I place that filters vapor out inline between the pump and sending unit? Only thing I could think of

[@TeeroyHammermill]

You had the hood open with the air cleaner off so it was able to dissipate heat quickly to mitigate potential vapor lock.

[@TheThirdWheel618]

Nice 👍 video thank you I have seen those fuel filters with a double outlet now I know why there used thanks . I switched to a small external elec fuel pump and 1" plastic spacer on my old 69 Ford it did not have any emissions stuff not even a vent in the tank it had a vented cap and that's were my problem was I had vacuum instead of pressure in the tank ?? And it was fighting against the small 5-7 psi pump so much that I was getting fuel starvation similar to vapor lock but it was the cap diaphragm failed and allowed it to suck in vacuum instead of pressure. I want to add a fuel return to the tank do you think that filter will do that ?? I'm thinking once my lil elec fuel pump dead heads fills the fuel bowls and has pressure against it 7psi it will go through that other port and start going back through that line toward the gas tank ? Then when it needs fuel in the carb it will stop and go through the other port ? . I've seen a guy make his own makeshift return with the brass T fittings he just had the line to the carburetor being on the bottom ports and then the return being raised with an extension on the top so when pressure built up it would go through the top and go back to the carburetor.

[@CelGenStudios]

That filter should work as long as you size for the correct flow volume. I'm sure the V8's need something larger so you don't starve the carb out.

[@TheThirdWheel618]

@@CelGenStudios it originally had a two-barrel 390 so they gave it 5/16 for the line sizing that was great for a two-barrel since you only had one float bowl I used to run a 2 to 4 PSI small pump and I've never was starved for fuel . Once I put a 4 barrel in it I started to have starvation problems on the secondary so I'm going to switch to 3/8 " all the way through with the 7 to 10 psi pump my theory on that is when it free flows it will go right into the carburetor bowls but when it backs up or deadheads as they call it it will start to go backwards and go back into the tank until I use some of the fuel again and then it will go right back into the carburetor. I thought about using a fuel pressure regulator to do this and just adjusting it out so it doesn't regulate anything just acts as a bypass since it has a return port at the bottom. But I had seen a guy make a makeshift bypass using a brass t-fitting with the elevated top at the t doing exactly that once it deadheaded it went through the top tea and went back to the tank.

[@jeepsblackpowderandlights4305]

the solenoids on the throttle. are for a.c

[@lordterra1377]

You can just make a Phenelic spacer for the carb and you will never have vapor lock issues. Also the extra height on the carb might also give you some extra torque.

[@hook86]

Incorrect. Many engines A. cannot fit this option under the hood and B. Create so much heat a spacer doesn't cut it.

[@heidiheida511]

You will need to check if all the linkage works fine with a spacer.

[@lordterra1377]

@@hook86 Time for a hood scoop or cowl induction then. Modifying the linkage isn't too hard but you can also put wood close pins on the fuel lines to act as heat sinks. Old hot rodding trick from back in the day. If it doesn't fit you make it fit. Simple.

[@lordterra1377]

You can also make whats called a cool can as a temp fix. A few companies still sell them even.

[@jimmierandall9571]

He pointed to the spacer he has installed at the first of the video, I put those plastic spacers on my flathead with zero effect.

[@quewat3676]

On your fuel return line ..you stated that you installed a check valve...which direction (fuel flow.or arrow)..did you installed the valve?

[@CelGenStudios]

The check valve allows fuel to be sent back to the tank and cannot be forced backwards into the filter/vapor separator.

[@quewat3676]

@CelGenStudios ..got it thank you

[@omarjassar4650]

Thank you for explaining it to us Mercans 😂😂

[@CelGenStudios]

No problem!

[@davedegan12]

Good info. Thank you

[@jimgee2676]

somebody told me to put the fuel filter with 1/4 return on it and to put a t fitting on my line and conect the 1/4 inch hose into the t fitting cause i aint got no return fitting on my sending unit or tank

[@martinreed5964]

my 73 v8 gucci sportabout suffers from vapour lock here in uk. Emission gear has been removed in the past, my problem is the engine cutting out when hitting slow driving conditions after a run out. Starts up fine after a cool down period. I have insulated the lines in the engine compartment, and wrapped the exhaust manifolds (not much air space under that hood with the v8 in there) , I do have a small electric pump on a switch used for priming the system after long resting periods but it still runs on the mech pump .I am about to fit the fuel filter from a jeep and run a return line back to the tank via the filler neck....I hope this cures my problem.....Im guessing that the fuel boiling is also the cause of the poor fuel consumption due to the recent introduction of ethanol blended fuel here in UK......I get the feeling that there is no way I can improve that even with the new return line ...what do you think

[@WilliamMunny-d8s]

WOULD AN ELECTRIC FUEL PUMP WITH 4-8 PSI FOR CARBS SOLVE THIS BY ALWAYS PUMPING GAS AND RETURNING IT TO THE TANK? would an in tank electric pump be best?

[@CelGenStudios]

Possibly? The idea is you run the pump for a few seconds before you try and crank the engine so that any bubbles that developed in the line will be forced purged down the return line. I do not advise using in-tank pumps due to many having issues requiring immersion cooling.

[@erebusreactor24]

Great video! Quick question though- out of the return line on the filter... does any liquid fuel actually come out of there? I am getting one of these filters that has the small orifice inside it which is designed for fuel tanks that don't normally have a return line and was wondering if I could integrate my fuel filter with a tee piece connected to the "tank" line on my charcoal canister.

[@CelGenStudios]

Yes. Any fuel not needed by the carburetor because the needle valve has closed is forced back to the tank so at any time you can expect vapor and liquid fuel in that line.

[@VareaIII]

I have a g body with a vapor lock issue. I was wondering if I could run a hose from the vapor outlet on the filter to the "carb" spot on my charcoal canister as a return line?

[@CelGenStudios]

The return line on a fuel filter should never be connected to the charcoal canister directly. It has to go back to the tank first and then back to the canister or else you will flood the canister with fuel until it overflows and spills gas into your engine bay, starting a fire.

[@VareaIII]

@@CelGenStudios I tried yesterday. Thankfully the hose didn't fit 🤣🤣. I unhooked the canister to use vent line as a return line and removed my gas cap temporarily. I plan on running the return line the correct way next week. But the filter in combination with heat shield definitely did the trick. Thanks for all your help!!

[@exoscrewdriver4213]

So that is the charcoal canister that needs replacing when the fuel gets topped up and comes gushing out of the gas outlet?

[@CelGenStudios]

Normally yes, if you get a gas-logged charcoal filter from overfilling it needs to be replaced.

[@nursecuenca]

Awesome video. I have 1965 c10 with 350 small block engine. When I drive over on 1 hr and if its hot the engine take 10 minutes to restart. I get no click and no crank. Healights turn on. Do you think adding vapor filter will solve my problem?

[@tacotimeracing6638]

Hi Nick, that doesn't point to vapor lock and the problem is something else. I have had starters with the solenoid made into it get old enough that when they are hot they wont crank. You might try looking at that.

[@jimgee2676]

i have a 1970 and it has vapor lock , but i dont have a charcoal system , if i use that fuel filter and run it back to the tank will it take care of the vapor lock

[@CelGenStudios]

It may help with part of it. The idea is the filter acts as a pressure relief and a vapor separator that sends anything excess back to the tank.

[@InternetDude]

How is your hood release not broken? 😉

[@CelGenStudios]

That reminds me. I gotta regrease that.

[@InternetDude]

Side note, does your A/C work?

[@CelGenStudios]

It doesn't have AC, period. This has a factory AC delete so it has a different climate control panel, air box and even the alternator bracket is different. That sounds cool (pun) until those three or four weeks a year you wish you had AC.

[@InternetDude]

@@CelGenStudios ah OK my car has the stuff but it doesn’t work

[@CelGenStudios]

@@InternetDude Common failure are the O-rings and seals, followed by the evaporator.

[@thepenitent3633]

can this happen when turning an engine rebuild? I saw a little bit of smoke on mine, then it shut off, but it turned on this morning but I immediately turned it off. Keep in mind i had water in it only just to see for leaks. Do I need to empty the water now?

[@CelGenStudios]

Vapor lock is more an issue with how your fuel lines are routed rather than an engine defect. Smoke after a rebuild could be anything from new parts burning grease/dirt off after being handled or plastic components contacting the exhaust manifold.

[@thepenitent3633]

@@CelGenStudios thank you so much for your insight, im still learning as well.

[@regpeeler5509]

I think I have vapor lock. I have clear inline filter in between the machical FP and the carburetor and on hot days (over 70degreesF) you will see the fuel start to bubble. About 10 min after that you hear rthe car getting ready to shut down. Logic tells me different, but wanna ask anyways. You think a spacer between the intake and carburetor would help with vapor lock?

[@CelGenStudios]

A heat shield might help for when the engine is running, but when the engine is off and not running there not a lot you can do to prevent it otherwise. Also, the filter is a FRAM G-3583

[@bernietorres3576]

Did you need to vent your gas tank to add the return line and filter?

[@CelGenStudios]

The tank has a vent line that runs to the charcoal canister and does not use a vented gas cap. So there's three lines that run to and from the gas tank doing separate jobs.

[@nisw1918]

Alcohol 10% in fuel boils at 170 deg. F .

[@brandonpropterhoc]

I have a chrysler 318 efi... mine engine seems to be having vapor locking issues. Would you recommend doing this to fix that issue?

[@CelGenStudios]

I would assume a pressurized fuel system like EFI wouldn't ever run into vapor lock. I'm not actually sure.

[@brandonpropterhoc]

@@CelGenStudios well i get a blast of pressure when opening up my gas cap. I also notice my engine struggling to go when im on at a quarter tank of gas and i mainly only happens in hot weather...

[@CelGenStudios]

@@brandonpropterhoc Overpressurized tank? Is the charcoal canister plugged? Is the fuel pump in the tank and overheating when the tank gets too low?

[@brandonpropterhoc]

@@CelGenStudios i have no idea. And in all honesty my radiator just blew up on me this past friday so its at the shop right now. I know i could fix the radiator myself but i dont know what caused my radiator to blew up which is why its in the shop.

[@SB2o9]

My 2014 Honda Accord sport is doing this. Any ideas? Honda couldn't even fix it!

[@jacobrzeszewski6527]

I don't think so. Just because the symptom is the same doesn't mean the same cause. A 2014 Honda almost certainly doesn't have this problem. It's something else.

[@BigMealsSmallPlaces]

How many different ways can you find to say the same thing?

[@CelGenStudios]

Enough to make it a game on its own! :D

[@ricardoguerra9411]

@@CelGenStudios Good Answer !

[@tiger8559]

So this is what Joe Namath was talking about.

[@sp204b]

Sounds like me after taco Tuesday

[@shortyruff40]

Did not solve my vapor lock problem

[@Manuqtix.Manuqtix]

I also had vapour lock issues. My problem is the electric fuel pump. The fuel needs to cool down the pump and overtime the fuel gets hot

[@DumbCarGuy]

Save some time and throw that locking fuel cap away.

[@hereticapostate9560]

It was just vapor lock…vapor lock…vapor lock…vapor lock… 😂

[@OrangeSeagull]

That was a lot of bad information dude. Vapor lock is simple. Gas gets too hot in there, it boils and creates so much pressure in the line you cant get any gas through it any more, which in turn starves your engine/carb for gas. Having a escape route for the vapor allows fuel to still make it to the carb/engine. You cant have a lean condition and flood your engine at the same time. That's too opposite things, stop making long winded half assed videos

[@royhodge6260]

That's it I'm getting an electric car.

[@b-17wingman37]

Wrong ! That pressure in fuel tank is caused by a stuck purge valve and or in correct fuel tank cap . Period.

[@BubbyPlaisan]

I feel the urge to purge

[@PatRiot-]

Ok so make a video in response pointing out what you thought he got wrong

[@jacobrzeszewski6527]

This is an old car from before that stuff was common. And regardless, his point of the gas boiling was still made.

[@doranvee5944]

You should be a teacher fulltime. Maybe you are?

[@CelGenStudios]

Not a teacher, I can assure you that.

[@doranvee5944]

@@CelGenStudios Well you have a natural gift. Great job!

[@CelGenStudios]

@@doranvee5944 Thank you. I try to explain things without getting too detailed.

[@timbensette1312]

Explains how it happens, but NOT how to clear it!

[@andrewnichols1118]

my fuel filter has one hose on top one hose on bottom please help i have a nisson 1992 d21 hardody its my dailey and im not able to get too work