[GSO_Passater]

1999 V6, 2.8, AHA engine, 117,000 miles, rebuilt heads due to CCT shoe failure on one head causing bent valves.

When starting the car, there is no smoke, the engine runs fine. After about 5 minutes, there is a whitish smoke that generally thins but does not completely dissipate quickly. I have run the car as long as 30 minutes without the consistency of the smoke changing, higher RPM = more smoke. The smoke has a sweetish smell and not like oil burning, no blue.

Any suggestions?

If it is the head gasket, is there a way to tell from which head it may be coming?

These are not the first heads that I have replaced on this type of engine as it is my 3rd B5 with a V6.

 

[Ntrain2k]

Antifreeze. Either a head gasket, cracked head or a leaking intake manifold gasket in my experience.

 

[Tomvw]

Check for moisture in the plugs and/or cylinders, but if one side has failed from over-heating the other side is likely weakened.

 

[GSO_Passater]

The car has not been overheated to my knowledge. I know/knew the previous owner and he had no major problem until the shoe disintegrated.

If the coolant pressure cap is left off, it takes longer for the smoke to appear from cool engine start. I will run the engine up to temperature tomorrow, then pull the plugs to see if the offending head can be identified.

 

[Tomvw]

Was only one head removed ? If so, that will be the leaking head.
Were new bolts used when the head was fitted ?
The head bolts are TTY and must never be re-used.

 

[PZ]

Does the AHA have the throttle body coolant hoses like the ATQ? If so, the throttle body can be the source of the coolant.

 

[GSO_Passater]

Both heads were removed. The spark plugs all look good, but only have a couple of hours running on them. I will post those pics tomorrow

Paul, I thought the AHA has a little metal pipe piece where the coolant warms the throttle body, but I will remove the throttle body just to be sure.

Is there somewhere on the intake manifold where coolant could seep into the air stream? I may have to find a way to pressurize the coolant system without the car running.

 

[PZ]

The throttle body is the only place in the intake that coolant can leak. The manifold itself does not seal any coolant ports. I know the ATQ has coolant hoses to the TB, but I was not sure about the AHA.

Harbor Freight has a pressure tester kit that fits the Passat. Has the coolant level been dropping?

 

[GSO_Passater]

The white cloud is not dense, so it is not using much coolant. If it is dropping, I cannot tell because the car has only been run for 4 hours or less. I will go to HF for the pressure tester tomorrow.