New Head Gasket, Same Old Smoke

[RallyEclipse98]

As the title states, I recently changed my head gasket ('99 420a). I spent hours and hours researching, posting my questions to the forums, and buying all the recommended parts*. I got everything back together and started the car.

It started great and idle was very smooth. It was rough before the head gasket change but I think that was just because the throttle body was full of oil. The car was sitting in a heated shop at about 55* and nothing visible was coming out of exhaust pipe. After about three minutes, vapor came out nearly as bad as before I changed the head gasket.

The smoke continued. I couldn't clearly tell if it was white or blue. It seemed like a pale blue but the shop walls are white so it's deceiving. Since the repair, the engine has been running for a total of 40 minutes idling and putting around at no more than 25mph with some slight revving to see the smoke level increase.

I did everything by the book for this head gasket change. I love the car and will keep it for a long time so no short cuts were taken!

From my preliminary research, I am considering a few scenarios: 1) problem with piston rings due to overheating before head gasket was changed, 2) coolant still sitting in catalytic converter and muffler but will vaporize after a few days of driving

I changed the head gasket because it seemed to be the problem to me, a shop diagnosed it as the problem, and because 420a's are known to kill head gaskets.

What is your advice? Thank you very much for reading this! I really appreciate the help!

* Because I know someone will ask, I used a MLS gasket with copper coat and replaced the head bolts which I torqued to MLS standards.

 

[MEz]

Run a compression test to make sure its not the rings. But it is possible it could be a valve-stem seal leaking oil, did you change those or any gaskets/sealants when you replaces the HG? Another unlikely place but possible is your breather lines (from the valve cover to the intake).

 

[RallyEclipse98]

Run a compression test to make sure its not the rings. But it is possible it could be a valve-stem seal leaking oil, did you change those or any gaskets/sealants when you replaces the HG? Another unlikely place but possible is your breather lines (from the valve cover to the intake).

I had the head resurfaced, pressure checked, and inspected. I did it at NAPA and talked to the guy for like 15 minutes about it and he said everything looked good (he seemed very experienced).

I can do a compression check eventually. I'm away from the car now for 10 days.

Breather line comment: Do you mean the oil is spewing out of the valve cover, into the intake, and out the exhaust? I know the air intake pipe and throttle body were both very oily. Should I pull the intake, start the engine, and see what happens? Although I ran the engine for a few minutes right after the head gasket change without the intake on and no noticeable oil was spewing out.

 

[BogusSVO]

Do you know how the head was surfaced?

http://www.dsmtuners.com/forums/new...face-4g63t-cylinder-head-mls-head-gasket.html

http://www.dsmtuners.com/forums/cyl...0613-why-not-let-your-head-belt-surfaced.html

Even if the head was surfaced, if it was not surfaced for a MLS HG you can still have the same issues.

 

[RallyEclipse98]

Do you know how the head was surfaced?

http://www.dsmtuners.com/forums/new...face-4g63t-cylinder-head-mls-head-gasket.html

http://www.dsmtuners.com/forums/cyl...0613-why-not-let-your-head-belt-surfaced.html

Even if the head was surfaced, if it was not surfaced for a MLS HG you can still have the same issues.

I'll call the shop to find out if it was surfaced well enough for a MLS. I know I told them a MLS was going on. I had the head resurfaced, pressure checked, and inspected. The older guy who did it said everything looked great especially considering the engine had never been opened up and it has 176k.

 

[Lou98GSX]

with that kind of mileage i would have done a whole rebuild .

 

[BogusSVO]

Was the surface dull looking or shiny when you picked it up?

 

[RallyEclipse98]

Was the surface dull looking or shiny when you picked it up?

Very shiny. I'm sure they resurfaced it, I had to use brake clean and compressed air to clean the shavings out.

 

[Outdorsman]

Could just be excess crap burning off. I know when I rebuilt my head due to a blown HG, I had spilled some powersteering fluid and oil and coolant around the area on accident. Some oil was still left and it burned off in a few days. I would blow off blue smoke while driving it but it went away.

 

[BogusSVO]

If it was very shiny then a decent surfacer was used.

If it was dull, that would have been a rough cut, like a belt surfacer.

Sounds like you may have to go take it for a drive and heat the exhaust system up and burn it clear.

Just make sure the temp gauge works proper, and keep an eye on the coolant level.

 

[RallyEclipse98]

Could just be excess crap burning off. I know when I rebuilt my head due to a blown HG, I had spilled some powersteering fluid and oil and coolant around the area on accident. Some oil was still left and it burned off in a few days. I would blow off blue smoke while driving it but it went away.

Come to think of it, I also spilled some p/s fluid or oil or something on my block when I was cleaning it. I worked really hard to get it all off but maybe it still has some to burn off. I hope so!

If it was very shiny then a decent surfacer was used.

If it was dull, that would have been a rough cut, like a belt surfacer.

Sounds like you may have to go take it for a drive and heat the exhaust system up and burn it clear.

Just make sure the temp gauge works proper, and keep an eye on the coolant level.

Actually, my temperature gauge isn't working. However the fans only turn on for a little bit and then shut off again so I don't believe it's overheating. I will look into that as well:

http://www.dsmtuners.com/forums/mai...perature-gauge-not-reading.html#post153230298

And tomorrow I'll call the guy who shaved the head to see if he checked the valve seals.

 

[RallyEclipse98]

After speaking with the shop further, I was told they inspected the valve guides as well. They checked out okay.

 

[BogusSVO]

After speaking with the shop further, I was told they inspected the valve guides as well. They checked out okay.

The shop checked the valve guides? So they pulled the head, then the cams and springs, and removed the seals?

Thats about the only way I know to check the guides.

 

[jayson427]

well a little smoke wont hurt even if it is blow by. as long as your car stays cool and the HG doesnt leak i wouldnt worrie about it if everything else runs smooth. i had a 97 420a with 160k and bad rings/valves seals which i ran the piss out of it. i would take right turns so hard and it would blow smoke like crazy and it never blew up on me. i live in one of the hottest places in the country

but i think its oil build up or your getting blow by. have you ever had oil come out of your air filter when you shut off the car? i would compression check it and if its low use some lucas oil stabilzer or plan on a rebuild.

 

[RallyEclipse98]

The shop checked the valve guides? So they pulled the head, then the cams and springs, and removed the seals?

Thats about the only way I know to check the guides.

The guy up at the counter I spoke with said maybe they checked the tolerances... He didn't know exactly what they did. I talked to another guy in the shop and he said, "If you didn't ask for the valve seals to be checked, they probably weren't. I don't know though." No one knows anything around that place. The receipts are descriptive either.

 

[RallyEclipse98]

I still haven't had a chance to check the compression on the engine but I did see the car for a few minutes yesterday. I looked under the engine and right beneath the front cross member is a small puddle of oil. Didn't get a chance to investigate. I'm scared though because I don't believe there's a simple fix for an oil leak in that location!! Perhaps I do have a cracked block for the head gasket didn't seal right. I just worked so hard to get everything perfect I'm a bit sad now.

 

[95gstnate]

I would check the pcv system and make sure it is functioning properly. Also another possibility is did the deck surface on the block get checked for straightness because with the mls head gasket the deck surface should be prepared the same as the head surface for a proper seal.

 

[RallyEclipse98]

I would check the pcv system and make sure it is functioning properly. Also another possibility is did the deck surface on the block get checked for straightness because with the mls head gasket the deck surface should be prepared the same as the head surface for a proper seal.

Thanks for the reply!

Check the PCV system? What all would that entail? I have recently replaced the PCV valve and the hose that connects it to the VC. No air leaks or improper fitment...

 

[RallyEclipse98]

This past weekend I went home and was able to do a compression check with a good quality compression tester (FYI O'Riley's rental compression testers are terrible).

My numbers: 190 190 190 190

The numbers should read from 170 - 225 with the variation no greater than 25%. The car has 176,210 miles and the battery I was using was pretty weak so my numbers could be higher if I put a new battery in the car.

I took her for a short drive but I will put some miles on her as suggested. My educated guess is that the cat and muffler still have anti-freeze in them and that's why when the car gets warm it smokes white. The exhaust heats up and vaporizes the liquid.

Thanks for the replies to this thread! If the smoke remains after a few hundred miles I will update!

 

[dsmvenge]

I highly doubt napa does there own machine work in house. They probably just sent It out to a machinist. Its problably all the stuff that got spilt all over the place while pulling the head. I would do a wet compression test and it wont lie to you about whats goin on inside your block.

+ 1 on anything bogus svo tells you. I have learned a ton from reading his post over the years

 

[RallyEclipse98]

I highly doubt napa does there own machine work in house. They probably just sent It out to a machinist. Its problably all the stuff that got spilt all over the place while pulling the head. I would do a wet compression test and it wont lie to you about whats goin on inside your block.

+ 1 on anything bogus svo tells you. I have learned a ton from reading his post over the years

This NAPA location does it all in-house.

 

[keston95GS-T]

This problem seems to be your valve seals. I had the same problem with my car a few years ago.

 

[RallyEclipse98]

This problem seems to be your valve seals. I had the same problem with my car a few years ago.

It was just antifreeze sitting in the cat and muffler, thank goodness.

 

[98Spyder_GS]

How much did this all end up costing you and what did Napa charge to redo the head? Just curious to know as will have to do a water pump/timing belt change soon Good to hear it wasn't anything major too!