02 Silverado 5.3 White Smoke

[Gito]

Own a 2002 5.3L Silverado with 198,000 miles and have been experiencing white smoke at start up since 100k. It has not been consistent but usually happens in the morning...The white smoke has also been observed during the day but rare. I'm getting close to 200k and I'm currently trying to figure out multiple codes. These are the following codes:

P-430 Catalyst System Efficiency, Below threshold(bank 2) and
P-300 Random Misfire Detected

Recently replaced the 02 sensors and have not checked if one of the above codes disappeared. Will run to Pep Boys later this week to check codes..

Please Advise

 

[Warstud]

White smoke is usually associated with water from a blown head gasket... so check your coolant level. Otherwise it could just be moisture building up in your exhaust system overnight.

 

[Gito]

Coolant level does not change. Maintains proper level. White smoke out of the exhaust has been happening for close to 100k miles.

 

[02z]

Sounds like condensation to me...if the coolant level isn't falling there isn't much more it could be.

 

[Boomer]

Are you sure it is really white? It could be some oil burning off when you start that accululated in the cylinders from the slow failure of old valve seals. These can be replaced without taking off the ehads by using an air chuck in the spark plug hole with the piston at TDC. The air pressure keeps the valve from falling in while you remove the retainers and replace the seals. A good mechanic can handle this for you easily.

 

[Turk]

So, if you step on it when it's dark & car lights are in your rear view mirror, does it also blow out light colored smoke?

 

[Gito]

Originally Posted By: tpitcher
So, if you step on it when it's dark & car lights are in your rear view mirror, does it also blow out light colored smoke?



I will have to check that out next time I drive at night

 

[Turk]

Originally Posted By: Gito
Originally Posted By: tpitcher
So, if you step on it when it's dark & car lights are in your rear view mirror, does it also blow out light colored smoke?



I will have to check that out next time I drive at night


Reason why I ask is my vehicles always do that and I maintain them well with quality gas. Usually it's carbon in that situation.

 

[hounddog]

These are known for valve guide seals going south with age and mileage. Put a set of seals on it. Bet it clears that smoke on cold start.

 

[Gito]

Originally Posted By: hounddog
These are known for valve guide seals going south with age and mileage. Put a set of seals on it. Bet it clears that smoke on cold start.


Are valve guide seals the same as valve stems? Is this a DIY job for a shade tree mechanic? What is the cost at a stealership or Independent mechanic?

 

[SteveSRT8]

We have several GM 6.0's and 5.3's in fleet use.

In our experience valve seals are NOT a problem, even up to 400k miles. These engines are known for carbon build up in the heads and a bit of piston slap in the older versions.

They also have a problematic orifice type PCV that can easily clog up.

Kreen that girl first and watch it clear up fast.

 

[hounddog]

Not a shade tree job without air,spring compressor and know how. It is the seal that goes over the guide that the valve stem rides in. I bet its around a $400 job. Google it. I have handled MANY valve stem seal replacements on these engines. Plus what you describe is par for that issue.

 

[Gito]

Originally Posted By: SteveSRT8
We have several GM 6.0's and 5.3's in fleet use.

In our experience valve seals are NOT a problem, even up to 400k miles. These engines are known for carbon build up in the heads and a bit of piston slap in the older versions.

They also have a problematic orifice type PCV that can easily clog up.

Kreen that girl first and watch it clear up fast.


What do I clean and with what? Do you mean throttle body? Or run some type of cleaner thru the fuel tank?

 

[Gito]

Originally Posted By: hounddog
Not a shade tree job without air,spring compressor and know how. It is the seal that goes over the guide that the valve stem rides in. I bet its around a $400 job. Google it. I have handled MANY valve stem seal replacements on these engines. Plus what you describe is par for that issue.


Hopefully I don't have to go this route but the price is not too bad..thanks

 

[Bgallagher]

Originally Posted By: 02z
Sounds like condensation to me...if the coolant level isn't falling there isn't much more it could be.


+1 check your coolant level and if it doesn't change then I wouldn't worry

 

[SteveSRT8]

Originally Posted By: Gito
Originally Posted By: SteveSRT8
We have several GM 6.0's and 5.3's in fleet use.

In our experience valve seals are NOT a problem, even up to 400k miles. These engines are known for carbon build up in the heads and a bit of piston slap in the older versions.

They also have a problematic orifice type PCV that can easily clog up.

Kreen that girl first and watch it clear up fast.


What do I clean and with what? Do you mean throttle body? Or run some type of cleaner thru the fuel tank?



The product name is Kreen from Kano Labs. Order some and use it exactly as they describe. There are numerous threads in here about it. Great stuff.

 

[Gito]

Update,
Replaced all O2 sensors and P-300 Random Misfire is gone.

P-430 Catalyst System Efficiency, Below threshold(bank 2) was also taken care of. Right side Catalytic converter replaced with a Magnaflow 459006. P-430 is also gone and just passed smog on Saturday. I'm in California so its got to be right on or no pass. Just a note to all, different smog shops use books to reference the correct catalytic converter for vehicles. You are not supposed to use books because they become outdated on a regular basis. Use the CA Air Resources Board website for the most up to date info on correct and legal Catalytic Converters for your car or truck. The good smog shops will go straight to the internet website....

 

[Bgallagher]

Originally Posted By: Gito
Update,
Replaced all O2 sensors and P-300 Random Misfire is gone.

P-430 Catalyst System Efficiency, Below threshold(bank 2) was also taken care of. Right side Catalytic converter replaced with a Magnaflow 459006. P-430 is also gone and just passed smog on Saturday. I'm in California so its got to be right on or no pass. Just a note to all, different smog shops use books to reference the correct catalytic converter for vehicles. You are not supposed to use books because they become outdated on a regular basis. Use the CA Air Resources Board website for the most up to date info on correct and legal Catalytic Converters for your car or truck. The good smog shops will go straight to the internet website....


your MPGs should go up on it too.

 

[Gito]

This week averaged 17mpg. Will report 2 more gas fills in the next week

 

[Turk]

Originally Posted By: Gito
This week averaged 17mpg. Will report 2 more gas fills in the next week


Is the white smoke gone or still there??