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Discussion Starter #1
I've been getting smoke coming out of the tailpipe - it's mostly grayish so for a long time I thought it was oil, but my compression is excellent and the other symptoms didn't match. I ran a test and now I'm 99% sure it's antifreeze. Obviously the first thought is head-gasket.

So before I spend a whole lot of money and have everything torn down and put back together for an engine that has about 35K on it, can any of you think of anything else on these 2ZZGE's that could somehow cause antifreeze to leak into the combustion chamber?

Thanks for your help!
 

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Get a combustion gas tester from advance or autozone and test the coolant overflow bottle. If that tests positive, it is almost certainly the head gasket.
 

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Check your plugs

They should show you if there is any coolant leak
 

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If he has solid compression in all four cylinders it shouldn't be a head gasket? do the compression test again and leave on each cylinder for about 10mins or so if any of them bleed down that's the problem, blown gasket.
 

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I'm going with BHG. Leak down on a cold or hot motor (depending on when you see the smoke) or the combustion gas test thing or one spark plug that is really clean versus the others are all ways to check, as has been stated. It's not boosted, is it? As far as I know, there is no coolant in the intake system on a 2zz, but if you have a turbo, then that's always a source of oil or coolant.

My 22R motor would do that when hot. #3 was sucking in a little coolant over the years, until one day in a parking lot it sucked it all in.
 

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If it is your coolant, you should be loosing coolant from your system constantly and you should get a sweet coolant smell.

Head gasket failures usually supper pressurize you coolant system...from the very lager failure area. With the radiator cap off, it should spit out coolant when you start up your engine.

My guess would be a cracked cylinder wall or a cracked head. Either way, you will need to pull the head.
 

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Discussion Starter #8
Thanks for the great insights!

About 1/4 of a liter of coolant has been lost over the past year. The smoke seems to be slowly getting worse.

The exhaust doesn't have a sweet smell. I don't know why, but it really just smells like normal exhaust. It smokes whether the engine is cold or hot and more so when the engine is revved.

The spark plugs all look like the one in the image at the bottom of this post - there wasn't one that was more clean than the others. They all looked almost exactly the same. The buildup that is there seems to be really stuck in - it would require a knife or metal brush to scrape it off because a fingernail is too soft. I'm guessing it's just carbon. The plugs probably have less than 1000 miles on them. I believe Dr.Hess's theory is that the cylinder with the leak will be cleaner because the coolant would wash off the carbon - right?

The way I figured out that the smoke contained coolant was by cupping my hands around the exhaust for about a minute. There wasn't really any residue, no wet feeling, and no oil or strong gas smell. However, there was a very unmistakably strong smell that reminded me of those cough drops that numb your throat. So I started googling for the ingredients in those types of cough drops and one of the main ingredients is menthol, which from what I read, has a very distinct smell. It turns out that some antifreeze coolants use menthol, but many of the newer ones use a variation that has a similar chemical structure. I dipped a rag in the antifreeze and it just smells sweet, like normal antifreeze. I'm guessing running it through the combustion chamber is what caused the menthol smell to come out. My hands reeked of cough drops all day - even after washing them twice!

So in my mind, I'm convinced that there is antifreeze going through the engine and exiting the exhaust and causing the smoke.

Now the question becomes, where is the leak coming from. Is it possible that there is another location where coolant could get in other than the headgasket?

Mr. <@¿@> mentioned that it could be a cracked cylinder wall or a cracked head - so that's one possibility.

Dr. Hess mentioned that intake system has no coolant so I guess we can rule that out (it is supercharged, but the coolant system didn't require modification for the supercharger install).

I have not tried the combustion tester kit from autozone. Would that help me pinpoint the leak's location, or would it just tell me that I have a leak, (which I already know)?

I also have not tried the bleed-down compression test. Perhaps that would tell me which cylinder(s) could be affected? I can do that next weekend.

BTW, if anyone wants to see what the smoke looks like, I put a short video clip here:
. It was windy so the only way I could get the camera to pick up the smoke was to rev it a bit.

The main goal is to determine the leak location so I can make a good decision on what to do about fixing it. If it turned out to be something not too complicated I will just do it myself. However, if it's really a head gasket or cracked wall, then I don't have the tools or time to do it so I'll have to ship it somewhere far away and pay lots of dinero :panic:

 

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Your vid doesn't look like a coolant/BHG to me. Spark plugs all the same and with some (normal) soot. I think you're OK, if that's all you got.

Are you losing any coolant? Keep an eye on the level. Coolant through the exhaust smells sweet, like the coolant, not like menthol, in my personal observations. The exhaust gases in the coolant test only tells you Y/N on BHG. It wouldn't hurt to do a leakdown/compression test and the chemical test, but I think you may be over thinking this.
 

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Discussion Starter #10
I agree - it doesn't look like coolant - I would have expected it to be more white.

I tried the same experiment with my truck and after cupping my hands around the exhaust for a minute my hands just smelled like... my hands. With the lotus, it is a VERY strong unmistakable scent of menthol. Regardless of the color of smoke, I'm convinced it has to be coolant. I can't imagine that oil or gasoline would ever smell like menthol which just happens to be an ingredient in antifreeze.

And yes, it is losing coolant very slowly - 1/4 liter over the last year.
 

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That smoke looked blue rather than white. It is hard to tell on the video though. 1/4 Liter over a year is negligible in these cars. I would guess oil. It could be some oil leaking down from the head right? Or even some leaking rings. Oil smoke shows up long before loss of power. I think you should keep driving it until things start going south :) It's a Toyota, it'll hold up for a while.
 

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Any crack, in the head or cylinder, would give one or two adjacent plugs a different pattern. Since all plugs are equal, the only place a common coolant leak could do that is in the throttle body. There is a coolant loop that goes through the throttle body.

BTW, to properly read a spark plug, you need to photograph the inside of the plug...so you could see down in between the porcelain center and the body of the spark plug. You will probably have to set you camera to macro to be able to do that.

And the one plug you've posted does look washed...
 

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Discussion Starter #13
I agree the smoke looks more grey than white - and oil was my first thought too. I replaced the PVC valve, did a compression test (good compression), checked the spark plugs (no oil).

But can anyone explain how burning oil could smell like a numbing anesthetic? I wish I had paid more attention in chemistry class! It smells like:

1) Numbing cough drops (benzocaine, menthol - Cepacol | Home)
2) The smell of the numbing agent the dentist uses (usually benzocaine)
3) Numbing cold sore gel (camphor - Campho-Phenique: Treats Cold Sores and Relieves Pain & Itching )

The car smokes worse when driving it. The last time I drove it, someone tried to wave me off the road. It smokes all the time - hot or cold. I'm pretty sure that's not good for the O2 sensors or the engine to be running coolant through it. And I doubt it's good to breath in those toxic fumes either.
 

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Discussion Starter #14
The spark plugs probably look so clean because they have less than 1000 miles on them.
 

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Warm the car up, then pinch off the coolant lines going to the throttle body with some needle nose vice grips and see if it does it. Get the coolant test kit from the auto parts store.
 

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This isn't going to be the answer, but I'll put it out there - does your car have an aftermarket exhaust? Burning packing?
 

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Discussion Starter #17
It has the stock exhaust with a larini decat. The decat is fairly new - maybe 8 months old. I didn't see any packaging stuck in it when I installed it, but it's a big s-shape and in theory there could have been something jammed way down in there.
 

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Plugs have oil on them based on that pic. That is not how the plugs should look.

Cracked block or cylinder head is about 0.01% possibility. That just doesn't happen on these motors.

The head gaskets can blow but not common. Compression test often won't find a pinhole as the hole expands with heat and combustion... Very not common on lower output motors unless she was detonating.

It's quite common for blow by oil to end up in the intake path which will give you smoke like that.

Also common for cracked ring lands resulting in an oil burner that may not show in a compression test. Didn't you have a bunch of tuning issues on your car? Detonation induced ring land damage as a result? If that's the case, you had better park it before the piston lets loose and destroys your cores... just say'n...

Looks like it's teardown time in any event...

Hope that helps,

Phil
 

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Discussion Starter #19
It looks like the plugs are oily, but it's deceiving because they were completely dry - I tried scraping it off with my fingernail but it was baked on there really good. Unless maybe you mean the oil got baked on somehow...

Actually it did backfire a couple of times after I put the larini decat on. It wasn't groundshaking loud, but it did pop a few times. I think that's what you're referring to as "detonating" right?

Yeah, I had tuning issues for sure. Every couple of months it would throw a P0172 system too rich. A couple of times I got a P2647 - rocker arm actuator system stuck on bank 1. It was constantly throwing the P0420 catalyst system efficiency below threshold (basically every day) even though i put in that mini-cat pipe in front of the 02 sensor to fool the computer. I sent the ECU to vision function, but it's been smoking and I'm afraid to drive it long enough to find out of the codes went away.

I thought that because the compression was good (190, 200, 190, 205) that the rings must be good. But I see what you mean - maybe the oil rings are bad but the compression rings are still good.

That benzocaine/novocaine/camphor smell is what is throwing me all off. I've been learning a lot though - apparently the same scent is found in cocaine and vagisil lol!
 

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That benzocaine/novocaine/camphor smell is what is throwing me all off. I've been learning a lot though - apparently the same scent is found in cocaine and vagisil lol!
That's funny!
 
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