Some white smoke.

[Chris-280ZX]

When I turn on my SR20 turbo motor in the morning, I get some white smoke out the exhaust. I account that to the dew/humidity (yay Florida) and the fact that the car needs to warm up. While going through the normal RPM range, no white smoke is to be seen. However, if I idle for more than 30 seconds, it seems that I start to get a constant (but not large amount) stream of white smoke until I start going through the RPM range again. I've checked my oil (white smoke though, so I doubt that's the problem), coolant/water levels and everything seems to be fine. Only other smoke I get is at WOT, where I get a bit of black smoke (but I account that to running a little rich and burning some fuel).

 

I've heard a few things from blown head gasket to dying turbo. Car seems to run just fine though at the moment. Can't see any oil or anything in my water or vice versa. I'll be buying a compression tester this weekend to test that out. It was also suggested that I take it out on the highway for 15 mins...come back and let it idle and see if it produces the same results.

 

Any other thoughts/suggestions?

[SR240Z]

One of my friends who we did the swap for, has the exact same issue. He had upgraded to an Apex'i Metal headgasket but we compression tested and leak down tested his motor anyway and it was perfect.

 

so our first though after that was the dying turbo.

[Z-Gad]

It may be the turbo oil seals, but I would probably say valve stem seals. If it is an older motor, under vacuum conditions, oil can seep around aged or cracked valve stem seals and lead to your symptoms.

Regards,

Mike

[Chris-280ZX]

Valve stem seals I can deal with.

 

New turbo...okay maybe.

 

But if it's a head gasket...I'm going to blow one (pun intended).

 

I'm no mechanic, what's the best way to figure out which is the culprit?

[cheftrd]

Smoke on start up is valve seals. The SR's rocker system puts a side-load on the guides. This wears out valve guides pretty quick, and this in turn wears out seals pretty quick. Almost every SR I've rebuilt needed new exhaust valve guides.

[FJ 280z]

yeah, i'd say valve stem seals also, if the seals on the turbo we're going bad, you'd probably see blue smoke.....

[Dunnie]

Burning Oil would be blue colored. White smoke would be coolant. If your turbo is not water cooled then it can't be the turbo, most likely the culprit is your head gasket going south. Just keep an eye on your coolant temps and level.

[Oldestzguy]

Dunnie is right, I am manager of Mercedes, Bmw, etc. repair shop. Here is my humble two cents worth.

 

1) Very small amounts of white smoke in the moring in Fl is just

overnight condensation burning off, IF, AND ONLY IF, there

never is any more smoke of any kind/color coming out after

it warms up and the water/condensation that forms in the

exhaust pipes overnight are gone. No job.

 

2) Bluish smoke is always oil being burned. If it is just when you

start it up in the morning and goes away when warmed up and

running; it is the valve seals that have hardened and are

letting small amounts of oil drip down into the cylinders while it is

parked. This will eventually get worse and worse. Easy job on most cars.

 

3) White smoke that seems to come and go is symptom of head

gasket failure and wll definitely get worse. If you have a minor

leak/crack that expands as the engine warms up, as well as,

when you accelerate; the power and heat from the cylinder is

pushed into the coolant areas. Oil does not actually need to be

present in the coolant system because it depends on where the

head gasket is leaking for this oil to travel across.

 

Cadillac Northstars are known for this and can go for months until

they finally overheat enough to ruin the motor. Mid-ninety's Saturns

actually have a new head availabe now to replace the factory ones

that were defective.

 

4) Black smoke is almost always too much fuel.

 

I think you have a very small head gasket crack in an area that

doesn't cross the oil system, yet expands and lets the heat and

pressure from the pumping piston into the coolant system.

 

Try this; let your car heat up, then race the motor for a while and

CAREFULLY, VERY CAREFULLY see if the radiator hose becomes

very hard or even tries to form a huge bubble.

 

This is very dangerous, you don't want to get scalded. SO BE VERY CAREFUL.

[cheftrd]

Dunnie is right, I am manager of Mercedes, Bmw, etc. repair shop. Here is my humble two cents worth.

 

1) Very small amounts of white smoke in the moring in Fl is just

overnight condensation burning off, IF, AND ONLY IF, there

never is any more smoke of any kind/color coming out after

it warms up and the water/condensation that forms in the

exhaust pipes overnight are gone. No job.

 

2) Bluish smoke is always oil being burned. If it is just when you

start it up in the morning and goes away when warmed up and

running; it is the valve seals that have hardened and are

letting small amounts of oil drip down into the cylinders while it is

parked. This will eventually get worse and worse. Easy job on most cars.

 

3) White smoke that seems to come and go is symptom of head

gasket failure and wll definitely get worse. If you have a minor

leak/crack that expands as the engine warms up, as well as,

when you accelerate; the power and heat from the cylinder is

pushed into the coolant areas. Oil does not actually need to be

present in the coolant system because it depends on where the

head gasket is leaking for this oil to travel across.

 

Cadillac Northstars are known for this and can go for months until

they finally overheat enough to ruin the motor. Mid-ninety's Saturns

actually have a new head availabe now to replace the factory ones

that were defective.

 

4) Black smoke is almost always too much fuel.

 

I think you have a very small head gasket crack in an area that

doesn't cross the oil system, yet expands and lets the heat and

pressure from the pumping piston into the coolant system.

 

Try this; let your car heat up, then race the motor for a while and

CAREFULLY, VERY CAREFULLY see if the radiator hose becomes

very hard or even tries to form a huge bubble.

 

This is very dangerous, you don't want to get scalded. SO BE VERY CAREFUL.

 

Both of you guys are wrong. White or blueish SMOKE is oil burning. White STEAM is coolant. There's a un-mistakable smell and dissipation rate between burning oil and steam. Oil smoke lingers and stinks like burning oil. Coolant steam dissipates quickly and stinks like coolant. White or white with a bluish tint smoke, that stinks like burning oil, out the pipe on first start-up in the morning is valve seals.

[Dunnie]

Both of you guys are wrong. White or blueish SMOKE is oil burning. White STEAM is coolant. There's a un-mistakable smell and dissipation rate between burning oil and steam. Oil smoke lingers and stinks like burning oil. Coolant steam dissipates quickly and stinks like coolant. White or white with a bluish tint smoke, that stinks like burning oil, out the pipe on first start-up in the morning is valve seals.

 

Ok....re-read the post you quoted and notice all you did was sum up what he said. Where I come from, coolant doesn't stink, it's sweet smelling but burning oil/overly rich on the other hand does stink.

 

_________________

Dunnie Morgan

My Garage

Dirty South, USofA

[cheftrd]

Ok....re-read the post you quoted and notice all you did was sum up what he said. Where I come from, coolant doesn't stink, it's sweet smelling but burning oil/overly rich on the other hand does stink.

 

_________________

Dunnie Morgan

My Garage

Dirty South, USofA

 

 

Stinks like coolant= Smells like coolant. OK, now you re-read my post, because you missed the point entirely. Water or coolant coming out of the tail pipe in a white plume is not smoke, it's steam. Both of you guys reffered to white steam from the muffler as smoke. Steam is very distinguishable from smoke. This is also not a nitpickey point. It's a very important distinction in diagnosing engine ailments. This is ASE 101, brother.

[Dunnie]

Stinks like coolant= Smells like coolant. OK, now you re-read my post, because you missed the point entirely. Water or coolant coming out of the tail pipe in a white plume is not smoke, it's steam. Both of you guys reffered to white steam from the muffler as smoke. Steam is very distinguishable from smoke. This is also not a nitpickey point. It's a very important distinction in diagnosing engine ailments. This is ASE 101, brother.

 

I get your point more than you assume. Yes we did word it wrong as smoke refering to coolant burning, when it would actually be steam and does dissapate quickly (I run w/i and have had the check valve stick open). A very small amount of oil burning could be interpreted as white smoke, so I'll stand corrected now.