CJ& 258 I6 High Oil Pressure

N2Jeeps

New Member
Joined
May 15, 2006
Location
Raleigh
CJ7 258 I6 High Oil Pressure

I have an 86 CJ7. The guage is registering 80 PSI. I replaced the sensor and that is not it. It starts at about 45 psi and then shoots up to 80 psi. Any ideas on what is causing this?
 
Oil Pressure

I already know it is high. I am getting oil blowing back into the air filter pan. I am trying to find out what would cause the high oil pressure.
 
Oil in the breather is either a bad crankcase vent or rings shot, it has nothing to do with oil pressure. If you were running 80psi on a 20 year old motor, oil would pouring out of every seal in it. I've built a lot of engines i'm not just blowing smoke up your ass....
 
When compression leaks inside an engine it doesn't take much to push oil up the crankcase vent. This does not mean there is enough to cause it to smoke, I know you have heard the term blowback this is exactly what that is. When it leaks past the rings it can escape past the cylinder walls an pressurise the oil pan with vaporized oil in a gas form which blows up through passages in the block, At this point it goes up the PCV an accumilates in the breather it doesn't mean the engine is shot it just has some miles on it.I am confident that your problem is a and faulty guage and a little mileage. If the rings are worn the oil in the breather is something you will have to live with.
 
Well said Maverick. To that i will add, Blow back or blow by as I have always called it, is pretty common in all engines with age. I have run an engine with blow by for years and it still worked strong, and ran well. But it didn't smoke. The factory gages to fail. For very little you can put a mechanical gage on yours. I do recommend also getting an up grade if if it does not come with the copper tube. I have seen too many of the plastic ones fail, and then you have a whopper of an oil leak.
I think your PCV valve(positive crankcase ventilation) is in your valve cover. Also make sure with a simple check of the top of the head, that your oil return holes are not clogged. Check the PCV and make sure it is functioning properly.
After doing all of this, you can help the symptoms with an oil additive like Restore, which claims to fill in voids on cylinder walls, to lesson blow by. More oil changes will help too, to lesson the blow by to keep the viscosity break down to a minimum.
Maybe not a good question, but did you do any re-routing of vacuum hoses recently?
Bottom line, still sounds as if you have two issues. Gage malfunction, and an aging engine.
 
Your correct on the terminology, old habit of being raised around oldtimers who's slang for terms, being that the air makes it back to the breather from which it started on intake , is where they got it from.
 
Could it just be valve guides and seals?
 
Back
Top