 
     |
| Blue smoke when decelerating - worn valve stem seals? (Page 1/1) |
|
Mike in Sydney
|
SEP 11, 03:33 AM
|
|
So here's the background...1986 GT with original V6, new distributor, Catback exhaust, 106,000 miles, 10W30 oil. Compression good, car starts easily, light puff of blue smoke on start-up that goes away pretty quickly. My diagnosis for this has been worn or aged valve stem seals for a 33-year old car that let oil dip into the combustion chamber.
Today, while coming down the major highway at speed (~65-70 mph), I took my foot off the gas getting ready for a turn onto a secondary road to my house. The road is downhill at this portion of the trip and I usually come off the gas and let the engine help slow the car. Today when I did this, I noticed that there was blue smoke (not fogging mosquito level, but noticeable) coming from the exhaust. After I made the turn and accelerated, the smoke went away. I punched the accelerator expecting to see more smoke but saw nothing. I'm guessing this is the result of the worn valve stem seals and an increase in vacuum pulling oil past the seals. What do you think?------------------
Mike in Sydney
|
|
|
|
Patrick
|
SEP 11, 04:08 AM
|
|
It's probably your valve guide seals, but make sure your PCV system (especially the valve, which is cheap to replace) is functioning properly.
|
|
|
|
theogre
|
SEP 11, 02:22 PM
|
|
Stick cars can suck oil thru valves and/or rings when you "engine brake" the car.
Auto cars can do this too but not obvious until is a really bad problem in most cases.
Can be oil drains block w/ crap keeping oil in the head. Look thru oil fill hole etc to see if the head is very wet to puddling oil there. Most engines should be wet but flooded w/ oil on the head.
Can be iffy valve seals.
Can be iffy valve guides too.
"Cheap fix" is replace the seals but know that may not help much if the guides or pistons rings are worn.
Check PCV system and make sure drains holes in the head to bottom end isn't blocked. If needed to clean drains try small bore gun cleaning kit w/ brush tips only.
Fix it ASAP.
Burning oil can wreck O2 sensor and Cat very easy.------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
|
|
|
|
Notorio
|
SEP 13, 12:01 AM
|
|
|
Your rubber valve stem seals have disintegrated into little chunks. Patrick has a nice thread on how to pull off the valve covers w/o removing the intakes (but I'm too lazy tonight to actually look for it).
|
|
|
Patrick
|
SEP 13, 12:24 AM
|
|
|
|
|
