White exhaust smoke, overheating
Thread Starter
Instructor
Joined: Nov 2017
Posts: 161
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From: SF Bay Area
White exhaust smoke, overheating
I'm troubleshooting some issues on my 02 C5Z where I'm getting a bunch of white smoke under hard acceleration, and some overheating. The strange part is that I just recently within the past 5k miles replaced the head gaskets, and I don't have any milky oil -- it's clean.
Suggestions?
Suggestions?
Instructor
Joined: Mar 2021
Posts: 124
Likes: 93
I'm sure someone with more knowledge than I will chime in soon, but it sounds to me that what you are seeing is not smoke, but steam. Is it coming out of both pipes? Your recent head work may be a clue. It sounds like you are burning coolant, maybe your gaskets aren't seated good, head bolts not torqued to spec..possible cracked head..etc. In the meantime a leakdown test might help narrow it down. Maybe try posting in C5 tech...good luck and keep us posted
Banned Scam/Spammer
Joined: Mar 2007
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From: Indiana Cornfield
Ok, here's a shot in the dark. I once pulled some heads off an Olds and a lot of coolant got dumped into the exhaust manifolds. I fired it up after the job was done only to see steam coming out the tailpipes.
I called a good friend who told me to drive it up a hill to empty the exhaust. He had done the same thing as I had and had changed his head gaskets 3 times trying to hunt down the problem. Who knows?
I called a good friend who told me to drive it up a hill to empty the exhaust. He had done the same thing as I had and had changed his head gaskets 3 times trying to hunt down the problem. Who knows?
Thread Starter
Instructor
Joined: Nov 2017
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From: SF Bay Area
I’m almost certain it’s the head gaskets also, I’m just not sure how they could’ve gone bad already and it scares me that it could just happen again. I had the heads resurfaced before putting them back on.
I forgot to mention that when I drive the car hard, coolant comes out of the overflow spout — so there is definitely air leaking in somehow. The temps have been spiking up to ~235 on an all aluminum radiator with hard freeway driving.
I have ARP head studs so taking the heads off won’t be too much of a challenge.i have the intake manifold off and I’ll be draining the coolant and pulling them this evening.
I forgot to mention that when I drive the car hard, coolant comes out of the overflow spout — so there is definitely air leaking in somehow. The temps have been spiking up to ~235 on an all aluminum radiator with hard freeway driving.
I have ARP head studs so taking the heads off won’t be too much of a challenge.i have the intake manifold off and I’ll be draining the coolant and pulling them this evening.
Last edited by CapslockAnt; Sep 16, 2021 at 12:02 PM.
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Le Mans Master
Joined: Apr 2012
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From: Brighton MI
OP, looks like your replacing one or both head gaskets again. Everything you have said points to the gaskets (assuming no issue with the heads or block). One poster asked if the white smoke is coming from one or both tailpipes. If you have a true dual exhaust with no crossover pipe of any kind, this would be a useful clue as to which gasket failed. But if you do have a crossover pipe, I am not sure this is helpful. Anyway, food for thought.
Best of luck!
Best of luck!
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Thread Starter
Instructor
Joined: Nov 2017
Posts: 161
Likes: 5
From: SF Bay Area
OP, looks like your replacing one or both head gaskets again. Everything you have said points to the gaskets (assuming no issue with the heads or block). One poster asked if the white smoke is coming from one or both tailpipes. If you have a true dual exhaust with no crossover pipe of any kind, this would be a useful clue as to which gasket failed. But if you do have a crossover pipe, I am not sure this is helpful. Anyway, food for thought.
Best of luck!
Best of luck!
Once I have the heads off, are there any visual representations of a blown head gasket that will help me confirm?
Last edited by CapslockAnt; Sep 16, 2021 at 02:31 PM.
Pro
Joined: Oct 2020
Posts: 529
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From: Columbus, MS
Get an IR thermometer and take temps of each of the exhaust ports as they come out of the engine. You MIGHT be able to find a cooler one that would indicate where the problem is, or at least narrow it down. Best of luck to you, sounds like you've got a job ahead of you on this one.
Le Mans Master
Joined: Apr 2012
Posts: 7,818
Likes: 2,267
From: Brighton MI
Could be a cracked cylinder too, but I do agree that the gasket and head (in that order) are more likely.
OP - it makes sense that the white smoke is most prevalent at WOT, that's when cylinder pressure is highest.
OP - it makes sense that the white smoke is most prevalent at WOT, that's when cylinder pressure is highest.
Last edited by 4XLR8N; Sep 16, 2021 at 09:46 PM.
Drifting
Joined: Mar 2018
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From: New Jersey
If you start the engine with the coolant reservoir cap off and you let the engine warm up you may be able to see bubbles in the reservoir as you race the engine. If you do, you know the head gasket is blown. Some times the pressure in the cooling system will just push coolant into the cylinder or exhaust.
Race Director
Joined: Oct 2004
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To the OP: Why were the new head gaskets installed in the first place. Performance work, valve job, or??? If you had this problem before the new gaskets were installed, I'd say bad head(s), but it's unlikely BOTH heads are bad, or a cracked cylinder/block. A bad head gasket can do what you're describing, with no coolant in the oil, or vice versa. With ARP studs, did you use the ARP assembly lube? It's a very important part of the install, otherwise you'll show the heads at the proper torque value, when in reality, they might be 10/20/30ft/lbs too low!!! Best of luck, and hope this helps...
Race Director
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The smoke comes out of the entire exhaust, and is much more prevalent under WOT / high RPM (ie: huge clouds). Would a cracked head or block be leaking coolant? I don't see any coolant near the heads or around the block, although under the radiator there appears to be a bit of fresh coolant -- I'm assuming this is from the air pressure in the cooling system forcing coolant out via radiator/reservoir.
Once I have the heads off, are there any visual representations of a blown head gasket that will help me confirm?
Once I have the heads off, are there any visual representations of a blown head gasket that will help me confirm?
Le Mans Master
Joined: Jul 2010
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Do a psi test and when did u change head gaskets?? Like up above said antifreeze gets into exhaust and takes a little bet to evaporate. Did this many times. i changed heads i freaked out. He needed the car that day. Drove it for half the day and all was good. Like i said dont know when u changed gaskets.
