I will watch the coolant level. I'm feeling better about things, especially with all this help. 
White Smoke
Thread Starter
Instructor
Joined: Nov 2004
Posts: 195
Likes: 0
From: San Bernardino & Orange County CA
White Smoke
Posted same question in General Discussion, then realized this might be the better Forum. Thanks. :o
My ’85 Coupe smells rich, yet it just passed smog with flying colors. Occasionally white smoke comes out of both exhaust pipes upon startup (usually after a short run to the 7-11). This doesn’t happen every time. No smoke on startup after sitting overnight or for moderate period of time or during runs. Not burning oil. It’s a SOCAL car so not starting up in extreme cold. The top end was rebuilt about 30,000 miles ago. Compression is good. Engine runs smooth and strong at idle and under acceleration.
Should I be concerned? I just bought the car a couple of weeks ago. Are these new fandangled additives like z-max worth considering or are they junk science? What about Lucas products which seem to be sold at truck stops & now the higher-end automotive retail stores? Freaking out – the previous owner maintained the car religiously, but it does have 160,000 freeway miles on it.
Thanks!
My ’85 Coupe smells rich, yet it just passed smog with flying colors. Occasionally white smoke comes out of both exhaust pipes upon startup (usually after a short run to the 7-11). This doesn’t happen every time. No smoke on startup after sitting overnight or for moderate period of time or during runs. Not burning oil. It’s a SOCAL car so not starting up in extreme cold. The top end was rebuilt about 30,000 miles ago. Compression is good. Engine runs smooth and strong at idle and under acceleration.
Should I be concerned? I just bought the car a couple of weeks ago. Are these new fandangled additives like z-max worth considering or are they junk science? What about Lucas products which seem to be sold at truck stops & now the higher-end automotive retail stores? Freaking out – the previous owner maintained the car religiously, but it does have 160,000 freeway miles on it.
Thanks!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
White smoke is actually steam, indicating coolant getting into the combustion chambers. Your's doesn't sound serious, yet. Keep a close eye on the coolant level. It could be an intake manifold gasket or a head gasket.
RACE ON!!!
RACE ON!!!
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
A byproduct of combustion is water and that's why there are weep holes at the rear of the stock mufflers. Depending on temp and humidity, a little white smoke, on startup is normal - it's just steam. Don't worry about it unless there's a coolant loss and even then, there will be other signs, like a less than perfect idle and poor performance if it's sucking coolant.
Advanced
Joined: Jul 2004
Posts: 80
Likes: 0
With all due respect to the senior members, white exhaust smoke is not technically steam but water vapor, a product (not a byproduct) of combustion (perfect combustion yields CO2 and water). And in your case, the water likely originated in the combustion chamber where it should have. Imperfect combustion (which is what we live with) yields about 200 other things, mostly bad. That's why there're catalytic converters and EGR valves. Cool pipes and/or cool ambient air temperature can allow the water vapor to appear until things heat up - happens all the time here in the Northeast, particularly in spring and fall. If coolant is leaking into the combustion chambers, you will continue to make smoke after warmup; just sniff the exhaust - your nose will tell you if there's coolant in the vapor.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Old182
With all due respect to the senior members, white exhaust smoke is not technically steam but water vapor, a product (not a byproduct) of combustion (perfect combustion yields CO2 and water).
Originally Posted by Old182
Cool pipes and/or cool ambient air temperature can allow the water vapor to appear until things heat up - happens all the time here in the Northeast, particularly in spring and fall. If coolant is leaking into the combustion chambers, you will continue to make smoke after warmup
Originally Posted by willi.anton
No smoke on startup after sitting overnight or for moderate period of time or during runs. Not burning oil. It’s a SOCAL car so not starting up in extreme cold.
RACE ON!!!
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Originally Posted by CFI-EFI
What is steam? H2O? What are water vapors? H2O? Is the energy level of the tailpipe emanation critical in the trouble shooting process? And does it make a difference if H2O is a product or a byproduct? Did you read the original post? I didn't say it HAD to be a coolant leak. I merely suggested he, "Keep a close eye on the coolant level."
RACE ON!!!
RACE ON!!!
Thread Starter
Instructor
Joined: Nov 2004
Posts: 195
Likes: 0
From: San Bernardino & Orange County CA
Originally Posted by comp
what is the air temp. there when you shut it off ???? is it cool ?
Advanced
Joined: Jul 2004
Posts: 80
Likes: 0
Whoa! Didn't mean to get nerdy on you or dispute your opinion! I thought it important to note that the appearance of water vapor is NORMAL and should be expected during certain conditions - that's all. It is a product of combustion as is CO2 (pollutants and other unexpected stuff are considered byproducts). Just didn't want you to scare willi into sleepless nights over it. My apologies.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
with everything said-I wouldn't get to concerned, just keep an eye on things. A little condensation does occasionally show up as you described. It's not unusual to even see it dripping from the exhaust at times-ambient temp. etc.