speedsecret

a friend of mine seems to have problem in his L48 engine in his 79 .
under strong acceleration or during shifting gears he has white smoke from is right exhaust { he got dual exhaust pipes from headers to muffler with out X or H pipe } so its seems like he has problem on the right side of the motor .
on idle there is no smoke. this is the original motor that the car left with from factory with 50000 miles on and still pull strong and sound good.

have any one here encountered in this kind of problem ? do we need to rebuild the engine or maybe it just the valve seals or something like that?

Rich's'78

white smoke is coolant (EG).

Roco71

I am not an expert here but isn’t white smoke from water? My first thought is to look for signs of water leaking into the cylinder head. I would first look to see what the water or coolant looked like in the radiator. What does the oil look like?
Then pull the plugs on the bank that the smoke is coming from and inspect the plugs and then compression check on each cylinder.
Just my first thoughts
Scott

thoyer

Good tips. Usually the offending cylinder's spark plug will be cleaner then the rest. Assuming that only one cylinder is being affected.

Also if he is burning coolant, the coolant level will decrease over time.

You could also do a pressure test on the cooling system.

Tom

blackcorvette1980

Is at automatic? If so does the smoke come when letting off the gas peddle, if so it could be transmission fluid being sucked in over the number 8 cylinder by a bad vacuum valve on the automatic transmission.

mr303

Sounds like a head gasket to me, do a compression test on the right hand cylinder bank.

SanDiegoPaul

Drive behind him & have 'yer windows down. Smell like oil?

I'm just saying that 'cause if it's just starting to burn oil, there may not be enough of a problem for it to smoke a lot. And it would look white. When/if a car starts burning a lot of oil, you'll actually see black spots of oil in the rear of the car.

OTOH, if it is blowing coolant, you would normally see an increase in engine temp and some changes in the radiator/coolant situation.

Attfay Elleybay

Glassbowtie77

White smoke usually is coolant, I would do a compression test and check for a bad head gasket or intake gasket.

7T1vette

I doubt that a compression test will find a slightly leaky head gasket. It might show up on a leak-down test, however. If it is coolant getting into the combustion chamber, it is either a gasket problem or a cracked head or cylinder wall. Head gasket is the most likely cause.

speedsecret

actually we didn't thought that its might be coolant fluid.
i talk to my friend and he said that he has some coolant lose but he don't think that its something serious . and the engine working in his right temp.
he also told me that in the last trip we made the engine loss/burn quarter gallon of oil on a 135 miles of driving!

so I'm still thinking that its might be oil


blackcorvette80 - yes the car is automatic but the smoke comes when he accelerating!

camber

what colour is the oil--if it's coolant/water the oil will change colour-mine turned a milky colour--camber

Paul L

Hold a section of white paper towel over the right exhaust tip, have him rev the motor for ~10 seconds, and check what colour the towel has become. If green you have your answer.

7T1vette

But, that's assuming he has 'green' coolant. [You can also get coolant in red, yellow and blue.]

noonie

A lot of people not familiar with this have trouble telling the difference between the white smoke (steam) and the very light blue smoke (oil or tranny fluid). If you really meant 1/4 gal in 135 miles then it should be pretty obvious or you also have a giant leak.

You said you have coolant loss, then yes there is a problem with the cooling system. You may also have oil burning problems in additon. Pretty common, even if it has only overheated once.

1-Small leaks/cracks can be intermittant and change with engine temperature.

2-Your engine may never show overheating until your coolant level becomes very low.

3-If you are seeing white smoke, then you likely have a combustion to coolant leak.

4-A cooling system pressure test may not work, because it can force the source of the leak closed (opposite direction)

5-A leak down test should show small bubbles in the radiatior neck after time.

6-You can force 120 psi compressed air into each cylinder with valves closed and rad neck bubbles will form.

7-Test fluid is available at most parts stores that changes color when exhaust gas is present, but it may not be sensitive enough for tiny leaks.

8-Use an exhaust sniffer like used for emmisssions testing.

9-Wipe your finger in the exhaust pipe and test for a sweet taste (if you're using coolant).

On a recent engine, just building too much coolant system pressure (over rad cap) over time was enough to show a head crack, no overheating, very little coolant loss, intermittant, no dye color change.
These sometimes are difficult to find and diagnose, but promp action is necessary.

Ghunt

I agree with NOONIE, compression is far greater than the water pressure (about 14lb compared to upwards of 200lb of compression). If a cracked cilender wall or head gasket you would see compression in the coolant tank (bubbles). If water in the exhaust look at the intake manifold/ gaskets where coolant would be sucked into the cilinder.
If your useing 2 qts of oil in 135 miles, theres your answer.

George