Diagnosis needed, where to look first?

[NHRA Super Gas]

I have started to notice white smoke from the exhaust at startup and when I pull up to a stoplight. Car still seems to run good and strong, Idles a little high and BL is high after a chip change. I added a quart of coolant yesterday, promptly disappeared. Added another one that has stayed level, so that may have just been low. Also have wet black smudge forming on the exhaust tips.

I drained the oil last night, nothing seems out of the ordinary. A little gas fouled, but I chalk that up to Reds chip. I replaced with a Turbo Tweak just the other day. I pulled one plug and it was a perfect color. I probably need to check the rest.

I can think of three things, none of them good:

Intake gasket

Head gasket

Piston Ring/Valve seals.

This motor is very fresh, so I'm skeptical about the last part. Only caveat there is the motor was broken in with Mobil 1 synthetic, so I'm a little paranoid about the ring seat.

OK, now I'll continue my prayer "I won't try to go fast again without alcohol, I promise".........

 

[Pronto]

Maybe you should pressure test the coolant system. If your oil is not turning bad it may be an intake leak.

 

[Black Car]

Loosing coolant isn't good.

After rebuild and break in, mine would run good but a little white smoke and loosing coolant.
Compression test showed 170 to 175 psi on all cylinders, so I doubted a blown HG. A friend of mine said it was head gasket and proved it to me.
I took it to his shop and he used an emmission sniffer normally for the tail pipe.
With the radiator cap off and engine running sniff the top of the radiator. If you get combustable gases, then you have bad HG(s).
Long story short, hair line blown HG.
Hope that isn't your problem.
Gary

 

[mikec1969]

Nhra,
Any luck with the diagnosis?

 

[NHRA Super Gas]

More

I am picking up the coolant system tester tonight or tomorrow AM.

I have a new theory to add to the above: Turbo leaking oil. Specifically, if the PCV isn't working, I understand you can have oil shooting out of the seals in the turbo. Anyone experience this?

Thanks in advance.

 

[Pronto]

white=coolant blue=oil Is your oil level dropping? You coolant has so I think you'll find something in the area.

 

[TurboBuickSix]

I am picking up the coolant system tester tonight or tomorrow AM.

I have a new theory to add to the above: Turbo leaking oil. Specifically, if the PCV isn't working, I understand you can have oil shooting out of the seals in the turbo. Anyone experience this?

Thanks in advance.

NO,the PCV valve or the lack of one would not affect the turbo seals in any way.The only time you will have oil shooting from the seal is if the seals are shot or improperly installed.White smoke is coolant and oil smoke looks white with a blue tint to it.I agree it can be hard sometimes to tell the difference especially if there is a small amount of oil.Oil smoke will hang in the air and float away,where coolant will smell like coolant and disappear a little quicker.Watch you oil level making sure it don't rise.If it is oil smoke I would think it is the break in with the synthetic in which case might go away sometime before you hit 10k miles

 

[Pronto]

They smell different too.

 

[NHRA Super Gas]

Maybe you should pressure test the coolant system. If your oil is not turning bad it may be an intake leak.

OK, anyone ever done this before? It appears my car will bleed down about 1 lb in the first two minutes, and then stay more or less the same from there. I didn't get instructions with the test, so I'm not sure if this is acceptable or not. Any experience here is appreciated.

 

[NHRA Super Gas]

One more time

OK, I did the coolant pressure test on both my GN and another car, and the result was very similar. In each case, the pressure dropped 1/2-1 lb in the first couple mins and then stayed constant. I'm assuming if you have a coolant problem, it wouldn't be this consistent.

I also had a look-see inside the THDP, and I didn't discover my smoking gun. I thought I might see oil in the turbo, but it wasn't the case.

I also inspected all 6 plugs thinking one might be "steam cleaned" but didn't see anything out of the ordinary. If someone has experienced the steam clean phenomena, I'd like to know if it was bright white like brand new or only subtly different from the others.

Tomorrow I'm going to track down some crappy dino oil and EOS, just to see how that impacts things. New PCV is on order, and last but not least a bottle of Bars Leaks just in case. These are better than pulling the motor :frown:

 

[Jerryl]

......... In each case, the pressure dropped 1/2-1 lb in the first couple mins and then stayed constant. I'm assuming if you have a coolant problem, it wouldn't be this consistent. ..........

Does it hold pressure when the engine is hot?
Could be a leak that only shows up on a hot motor at a hose, radiator cap, cracked head/block???

 

[NHRA Super Gas]

Does it hold pressure when the engine is hot?
Could be a leak that only shows up on a hot motor at a hose, radiator cap, cracked head/block???

From what I've read elsewhere, I think you're supposed to run the car with the tester installed, looking for fluctuations or increases in pressure. That is today's project.

EW

 

[LV GN]

what kind of headgaskets are on the motor? what state are you in? is it still cold out side when you start the car?

 

[NHRA Super Gas]

I'm in IL. It is not that cold, and when i discovered this problem was mid day, 70+ degrees. Car has cometics on it, hasn't seen more than 22lbs.

 

[LV GN]

I'm in IL. It is not that cold, and when i discovered this problem was mid day, 70+ degrees. Car has cometics on it, hasn't seen more than 22lbs.

all i can think of is to retorque the heads and all some GM cooling tabs.