fresh oil out of the tailpipe

shaun65Polara

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guys and gals

i drove my 65 polara to the carlysle show in 2021 and it ran so sweet. But on the way back, the water pump belt failed, engine overheated. Doing some roadside repairs, i changed the belt & eliminated what had cut it & also found that my engine oil lever was very low. I had extra water and oil with me and got back on the road. Some 200 miles later, including 5 stops to buy/add more oil, i made it home.

it's been parked since and just getting back into the country from overseas, i'm diagnosing best i can... I'm thinking its either 1 of 3 things ( or a combination ).

failed oil rings
blown head gaskets
burned exhaust valve seats ( i did not change the original seats on the original heads )

comments/suggestions are welcome ... & thanks
 
The items you mentioned do not fail suddenly, but over many thousands of miles. Even failed head gaskets can give some notice, IF noticed. Blown head gaskets might have caused the heat issue, but the radiator hoses would have also been "blown larger", too, I suspect.

To use that much oil, if it was using it, should have resulted in a blue smoke screen from the exhaust pipe. Of course, the spark plugs would have been overcome with oil and fouled, too.

Failed exhaust valve seats or burnt exhaust valve would have caused uneven running and/or a definite "miss" at idle, which would have been noticeable, too.

No leaks? For good measure look at the oil pressure sending unit, the rear main seal, and the oil pan drain plug.

Just some thoughts,
CBODY67
 
"Fresh oil out of the tail pipe". Do you mean liquid oil dripping from the tailpipe, or volumes of oil smoke? Did the engine overheat after the belt was replaced and the cooling system refilled? Are the spark plugs fouled? Is there oil in the coolant or coolant in the oil? How did the engine run after the overheat and roadside repair? Lindsay
 
"Fresh oil out of the tail pipe". Do you mean liquid oil dripping from the tailpipe, or volumes of oil smoke? Did the engine overheat after the belt was replaced and the cooling system refilled? Are the spark plugs fouled? Is there oil in the coolant or coolant in the oil? How did the engine run after the overheat and roadside repair? Lindsay
engine ran great with no noticable loss of power. The blowing oil is still fresh and clear brown, without any burning at all.
spark plugs are not fouled. I started it yesterday with just barely touching the momentary switch. Runs and idles great ... Just blowing fresh aerated ( not dripping ) oil out the back, clear of any coolant. Oil in pan is also clear of any coolant.
 
also found that my engine oil lever was very low
key word is "also". overheated because the belt broke. oil level was already low due to separate issue.
Some 200 miles later, including 5 stops to buy/add more oil,
never added any more coolant or experienced any more overheating. oil consumption only. pcv and crankcase vent hooked up and working correctly?
'
 
The items you mentioned do not fail suddenly, but over many thousands of miles. Even failed head gaskets can give some notice, IF noticed. Blown head gaskets might have caused the heat issue, but the radiator hoses would have also been "blown larger", too, I suspect.

To use that much oil, if it was using it, should have resulted in a blue smoke screen from the exhaust pipe. Of course, the spark plugs would have been overcome with oil and fouled, too.

Failed exhaust valve seats or burnt exhaust valve would have caused uneven running and/or a definite "miss" at idle, which would have been noticeable, too.

No leaks? For good measure look at the oil pressure sending unit, the rear main seal, and the oil pan drain plug.

Just some thoughts,
CBODY67
no leaks anywhere else, but thanks none the less
 
i'd give it a compression and/or leakdown test...or at least pull the exhaust manifolds to see where the oil was entering the exhaust
 
I have a hard time believing oil is making it all the way out to the tailpipe without blue smoke accompanying it. For fresh oil to make it from the headers thru the muffler (or no muffler) and all the way out the 12 plus feet to the tailpipe, there would have to be some special circumstances afoot. Exhaust manifolds heat up fast and that oil spray would be blue smoke quite fast. Maybe since it sat for two years there was some condensation build up in the exhaust mixing with a slightly rich cold engine? Oil smell like gas? Any video of this happening?
 
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so oil going from an oil galley directly to an exhaust port after overheating, but no consequences to the cooling system? let us know when you find it.
 
If I understand correctly, you are getting "oil" out the end of the tail pipe. Oil which first had to get into the combustion chamber somehow (valve guides/seals of up from the bottom via worn piston rings). Not enough to foul plugs, but it then transported via hot exhaust gases into the exhaust system and out the end of the tailpipe.

This oil would put a coating inside of the exhaust system, over time. Preventing "rust-out" in the process.

And all of this happens soon after the engine is started. THAT leads me to suspect the early-start-up condensate is what is being seen. With the oil being pushed out with the water, as oil is lighter than water, rather than "pure engine oil".

That's my theory.

CBODY67
 
"200 miles, 5 stops to buy/add oil". I had a low milage Datsun engine using 4 quarts in 100 miles. It had 17K miles and ran quite well, but would foul all 4 plugs if I didn't disengage the clutch when slowing down. Rings were shot. (that was the first and last Jap car for me!) Compression test might be a good idea. Lindsay
 
I have a hard time believing oil is making out all the way out to the tailpipe without blue smoke accompanying it. For fresh oil to make it from the headers thru the muffler (or no muffler) and all the way out the 12 plus feet to the tailpipe, there would have to be some special circumstances afoot. Exhaust manifolds heat up fast and that oil spray would be blue smoke quite fast. Maybe since it sat for two years there was some condensation build up in the exhaust mixing with a slightly rich cold engine? Oil smell like gas? Any video of this happening?

so oil going from an oil galley directly to an exhaust port after overheating, but no consequences to the cooling system? let us know when you find it.
i will
 
If I understand correctly, you are getting "oil" out the end of the tail pipe. Oil which first had to get into the combustion chamber somehow (valve guides/seals of up from the bottom via worn piston rings). Not enough to foul plugs, but it then transported via hot exhaust gases into the exhaust system and out the end of the tailpipe.

This oil would put a coating inside of the exhaust system, over time. Preventing "rust-out" in the process.

And all of this happens soon after the engine is started. THAT leads me to suspect the early-start-up condensate is what is being seen. With the oil being pushed out with the water, as oil is lighter than water, rather than "pure engine oil".

That's my theory.

CBODY67
silver lining in this cloud ... no rust in exhaust system !
 
I would replace the valve seals it not to hard of a job even with the heads on it can be done
 
new post today, to update this one. it may be hard for some to imagine, but before i tore it down, it ran like a scalded dog. 1 mile up a 10% grade, at 90mph: super powerful but that 1 mile cost a quart of oil.
 
So, you have tore it down by now huh? What was the issue?
 
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