Oil Pressure Drop - 82 CJ7

[jlawson]

I called about an 82 CJ7 for sale, and the guy said once it warms up, the oil pressure drops. What could be the cause of this, oil pump, valves, need a rebuild????? I wanted to have a little bit of an idea before I go and buy this thing.

It's an 82 CJ7 Renegade with a 258 w/ 104,000 miles and 5 speed.

So what's your opinion????

 

[far_right]

mine does it too, it just depends on how far it drops too

 

[jlawson]

Thanks for your input.

I was thinking it might not be too big of a problem, but since he brought it up, it made me stop and think... and where else to get advice!! I guess I'll know more after I drive it.

 

[avyoung]

Take a compression gauge and check it then you will know if it has a stuck valve or bad rings

 

[olyeller]

probably a combination of a worn oil pump and warm oil. while the oil is cool, it is thicker and builds more pressure. as it warms and thins, the pressure drops. i only have about 3k miles on a rebuilt engine and it makes about 70 psi when first started. after a few miles, the oil pressure drops to around 50 psi at idle.

 

[firemanharry]

Mine was running at about 20 PSI at warm idle, nothing out of the ordinary. Just take a look at the oil and listen for any knocking from the motor. Don't worry so much about what the gauge says, stock AMC weren't the most accurate. The 258's are good motors that are generally bullet-proof.

 

[Deerhunter30]

97 wrangler sport top fray

When I bought mine it would drop to about ten psi at an idle once warm. Then I noticed that he had a sticker form the local oil change place in the window. I checked my Haynes manual to see what oil they recomended just for kicks. It recomended either 20-50w or 30w for temps above 40 deg. It specifically stated NOT to use 10w oil in temps above 40 deg. Well I live just south of Houston, Texas and summer temps get above 100deg on a regular basis without calculating in heat index. I am pretty sure that most of these oil change places use 10-30w in all vehicles. I put some 40w oil in and now it only drops to about nineteen psi at an idle once warm. Just something to check on.

 

[Nymisus]

more cherokee repairs...crank window on driver's side

mine doesnt even work....just make sure it runs good and take a look at the engine...make sure there isn't oil all over it or anything and you're good to go