Oil Residue around PCV (Page 1/1)
sjmaye MAY 01, 06:23 AM
My 1988 GT engine is pretty tired. It doesn't have near the acceleration of my '87 GT. I assume the oil residue around the PCV is due to piston blowby. The oil residue is not too bad, but it makes me wonder if I do have high crankcase pressure what harm it may be doing to other seals and gaskets. Further, barring pulling the engine, what can be done to mitigate the problem?
Gall757 MAY 01, 09:03 AM
the 02 sensor will go bad more quickly, as will the CAT. Spark plugs should not last as long as normal....(which is forever). Change oil and filters sooner rather than later.
sjmaye MAY 01, 09:42 AM
The motor seems weak, but runs and idles fine. I was wondering if a certain amount of oil mist around the PCV on the valve covers was normal. I did not think so. I wondered about solutions that would reduce any back pressure or a maybe a catch can.
Gall757 MAY 01, 10:35 AM
Not normal but not unusual either. How many miles on the motor? Mine has 130K miles and does not have blow by.... If it sits a lot, you might have stuck rings which may respond to an additive. You can do a compression test if you want to know more.
sjmaye MAY 01, 10:48 AM

quote
Originally posted by Gall757:

Not normal but not unusual either. How many miles on the motor? Mine has 130K miles and does not have blow by.... If it sits a lot, you might have stuck rings which may respond to an additive. You can do a compression test if you want to know more.



I honestly have no idea how many miles are on the engine. I bought it used in 2007. It shows 95,xxx, but everything about it tells me it has more. Either that or this thing was abused in a previous life.
theogre MAY 01, 11:19 AM
PCV Seal and elbow and other "rubber" parts gets "Bad" just from age. Oil and heat can make them hard won't seal right.
Beside oil on valve cover etc. can cause vac leak anywhere on the vac line.

PCV Seal keeps liquid oil in and normal Blow-by too. Many V-covers have "guards" under PCV to stop major oil spray hitting the valve but some spray get to it. Extra blow-by from worm engine won't help a hard seal.

Replacement and OEM seals even new can have a film on V-cover too. Even different batches of PCV and seals have slightly different dimensions so replace PCV and/or seal w/ tiny different size change might make the oil film of V-cover after a few months or years.

Replacing the seal might not help much for oil film.
Plus any film oil hold dirt that holds more oil.

Example: I replace PCV Seal and even Valve cover on l4 w/ New one w/ new seals for PCV and still gets a small film at both. The V-cover Air intake side has nothing blocking blow-by to PVC air filter but PCV side still try to get a film build up. These new V-covers also get a new fill port w/ new cap to seal better.

"High Mile" engine oil tries to soften old seals but many seals after 20 - 30+ are too hard to help much or any. When they work, take time to do so.
Valvoline was first "High Mile" oil and was rated well by but now several brand have this too.

Aggressive chems in most "leak stop" additives many soften to much or have other problems. If you try them follow direction and don't add every time you change oil. I avoid any oil additives as many are just Snake Oil remedies.

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sjmaye MAY 01, 04:25 PM
The oil film is minimal. I have driven the car a couple thousand miles in the last 12 years. The valve covers looked like I had lightly misted oil on them and dust settled on that. Did not cover anything up. It just made it look dingy. The engine looked perfect when I installed it. It bothers me how it has aged.

I may just try replacing both the PCV valve and the seal around it. They don't fit tight at all.