Excessive oil consumption

Tiny
TERRYP
  • MEMBER
  • FORD MUSTANG
1967 Ford Mustang 289 small block engine. It uses excessive oil, about a quart every 500 miles. The exhaust does not show excessive smoking. I have replaced the valve stem seals. This did not slow the usage down. It has dual exhaust and when running engine sooty oil comes out of the tail pipes.I have run Marvel Mystery oil to try to loosen stuck piston rings. This has not helped.

Any suggestions as what my next step should be to try to stop the oil usage. Thanks
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Friday, March 2nd, 2007 AT 9:38 AM

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Tiny
M_H_RITZEL
  • EXPERT
Do a compression check on the engine. If the compression shows low on one or more cylinders could mean a blown head gasket or the rings a shot.
In that case the engine should be rebuilt, when you did the valve stem seals did you have the heads off?
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Friday, March 2nd, 2007 AT 8:11 PM
Tiny
INDYUKE
  • MEMBER
How many miles on the engine?

On the older 289 and 302's, (identical engines except for basically the piston stroke) the use of a quart of oil every 1500 miles is considered normal. Even a quart every 1000 miles isn't something to worry about. That's with umbrella type valve seals and soft iron rings. So the reason I ask the engine mileage, is because a worn out 289 will typically use a quart or more every 500 miles.

Check your PCV system.
Check for any vacuum leaks, you could have a leaking intake gasket that is letting oil into the intake runners.
Do a leak down test of all your cylinders. That will tell you whether or not your rings are badly worn, broken, etc.
Even though you replaced the stem seals, the valve guides themselves might be severely worn. The area below each intake valve is a very high vacuum area, and will pull oil right past the seals if the guides are severly worn.
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Friday, March 2nd, 2007 AT 8:36 PM
Tiny
CLEVELANDMAN
  • MEMBER
I would check the rope seal around the crankshaft at the back of the block!
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Tuesday, November 3rd, 2015 AT 8:23 AM

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