Head Gasket Symptoms

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xsports33

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I know some of the symptoms are low/missing coolant, coolant in the oil (milky appearance), misfire, white smoke out of the exhaust, etc...

question is regarding the white smoke. If i did blow my head gasket or cracked the cylinder head, would the white smoke be all the time or just at start up?
 
All the time.

If it goes away after a little driving, it's almost certainly just condensation in the exhaust.

If a HG leak is bad enough to produce white smoke, there are probably also other noticeable symptoms.
 
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If you're blowing white smoke due to a head-gasket failure, then your coolant level will be dropping.

Keep an eye on both the rad AND the reservoir. If they keep dropping, then you're burning coolant.

Do you have any hard-starting when cold, rough-running immediately after a cold start, or stumbling immediately after a cold start?
 
when i checked the coolant level, it was about 2 quarts low, but i just bought the vehicle about 4 months ago and never checked it until now. I refilled it to the hot line and 4 days later it's still fine... so not sure if coolant is missing... yet

i do have little "chocolaty" residue under the oil cap, but nothing on the dip stick or the last oil change. So, i'm not sure what that is about.

A little rough start and idle after a cold start (not driven for a few days).

My biggest indicator and concern is that there has been a very large white plume of smoke, that lingers, doesn't dissipate, out of the tailpipe when I cold start. It's only at startup, last for a few seconds, then i'm burning condensation.

any thoughts?
 
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You should be able to smell the antifreeze if it is burning, its a sweet smell. Head gaskets can do some weird stuff. I had a Caddy Seville and it would just boil over the coolant tank and be fine for a month and then just blow out pressure again. I finally sold it to a guy and he found a hairline crack in the head, after the head gasket was found intact. Smell your exhaust.
 
smelled the exhaust. it doesn't smell sweet. Smells like... exhuast, maybe a little rich, but no coolant or sweet smell. Honestly, it was the first thing i did and do it every time at start up. (remote start
smile.gif


It's a 2009 GMC Yukon Hybrid
 
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Originally Posted By: xsports33
when i checked the coolant level, it was about 2 quarts low, but i just bought the vehicle about 4 months ago and never checked it until now. I refilled it to the hot line and 4 days later it's still fine... so not sure if coolant is missing... yet

i do have little "chocolaty" residue under the oil cap, but nothing on the dip stick or the last oil change. So, i'm not sure what that is about.

A little rough start and idle after a cold start (not driven for a few days).

My biggest indicator and concern is that there has been a very large white plume of smoke, that lingers, doesn't dissipate, out of the tailpipe when I cold start. It's only at startup, last for a few seconds, then i'm burning condensation.

any thoughts?

Moisture condensed, usually from many short trips. A good drive on highway will burnt it off.
 
Put a bucket under the car. When the engine is cold, remove the radiator cap, and run the engine for a few minutes with the cap off. If there are bubbles coming up, that can be a sign of a failed head gasket. You will need that bucket there because some coolant will spill out when you do this.
 
Originally Posted By: Merkava_4
Stick the gas analyzer in the coolant reservoir and check for the presence of carbon.


Good no-[censored] way to find out for sure.
 
Originally Posted By: DoubleWasp
Originally Posted By: Merkava_4
Stick the gas analyzer in the coolant reservoir and check for the presence of carbon.


Good no-[censored] way to find out for sure.


This.....would be shocked to hear of head gasket failure on a decades old GM V8. If this was a Subaru boxer 4 or Nissan I-4 I would not be too terribly surprised. How Subaru and Nissan still can't get it right is beyond me, personally think that is an engineering project that should have been put to bed in the late 90's.
 
That white smoke will have a distinct odor to it.When my car blew a had gasket, it ran poorly and the coolant recovery bottle was overflowing.
 
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If your spark plugs are easy to pull...pull them. If one looks literally steam cleaned...you are burning coolant.

Milky coolant or oil is another sign. Also you could be blowing exhaust into your coolant which will cause the overflow to well...overflow.
 
Originally Posted By: 01rangerxl
All the time.

If it goes away after a little driving, it's almost certainly just condensation in the exhaust.

If a HG leak is bad enough to produce white smoke, there are probably also other noticeable symptoms.


I have to disagree with the first part- they won't always produce symptoms all the time. My Malibu only consumed coolant. No drive-ability issues, no smoke. I just got done doing head gaskets on my best friend/shop partner's 6.0 Chevy 2500HD- it would buck and smoke for a mile, sometimes two, then nothing. The gasket at #6 was cracked.



Originally Posted By: DoubleWasp
Originally Posted By: Merkava_4
Stick the gas analyzer in the coolant reservoir and check for the presence of carbon.


Good no-[censored] way to find out for sure.


Again I'll say "not always"...

Passing the combustion gas chemical test doesn't necessarily clear you. I've seen them pass, but still have a bad head gasket. However failing the test does mean that you're hosed...


O/P- the smoke produced by burning coolant is often times confused with the water vapor that typically comes out of the tailpipe. Easiest way to tell is coolant smoke will linger longer and be whiter in color. Sometimes it will have a tinge of blue in thinner parts of the smoke- like where it starts to dissipate. Sometimes it's easier to I.D. from a following car.
 
Check the coolant recovery tank while the engine is idleing.
If you see small bubbles rising in the tank, then the headgasket
has failed or the head is cracked.

If a fuel odor is detected at the recovery tank, the same thing applies. Or a sooty, carbon like film on the top of the coolant.
 
Originally Posted By: TheLoneRanger
Check the coolant recovery tank while the engine is idleing.
If you see small bubbles rising in the tank, then the headgasket
has failed or the head is cracked.

If a fuel odor is detected at the recovery tank, the same thing applies. Or a sooty, carbon like film on the top of the coolant.


+1, just do that while the engine is COLD!
 
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