ok to make this simple and short. 88 acc. lxi 230xxx miles guage installed, at idle 20 psi will hold for hours, i know i've tried. once i drive around for 15 min or so the pressure steadily drops. and will drop to 8psi. light comes on. turn off the car and restart pressure back to 20. then start all over again. if it were the the rod bearing wouldn't this show up at idle also. if it were the oil pump the same. anyone. this is a beater i'm trying to sell to rebuild my boosted d engine.

edit- i only have $400 in this car and i want to cut my losses if its done to the junk yard it will go.

 

Sounds like a clogged screen on the pickup in the oil pan. The harder it sucks, the more it gets clogged.

 

if that's the case why no trouble at idle. even under frequent revs and idling for hours?

 

It could be a combination of wear and the oil thinning as it warms up. It's not inconcievable that the rods & mains (bearings) are on the "loose' side of the specs from wear, which would (in effect) cause the equivilent of an internal oil leak/pressure loss point. Combined with the thinning oil (as it heats) (which flows easier), you could see a gauge pressure loss.
It COULD be, that as long as it idles under no load, it doesn't really attain the same oil temp as driving (and it doesn't thin as much.
Conversely, a worn oil pump would act much the same way. Because of increased clearances, the pump would loose pressure as the oil warmed up and lost viscosity.
Seeing (however) that the oil pump is arguably the most lubricated part of the engine, the chances of this are pretty remote.

P

 

i know it's impossible to say for sure but from what i gather from the last post P seems to think its wear and oil viscosity? i mean if it is the oil pump i could replace that. $150 going into a beater that i want rid of doesn't seem resonable if it doesn't fix my prob. also if its the bearings then the car is going to the yard. i do not want to replace bearings in this car with the engine in the car UGH. any other opinions or ideas. or just get rid of it. anyone?

edit- i may pull the oil pan tomorrow to check the pickup.

 

First thing I'd do b4 tearing into the high-miler, would be to locate someone who could help you confirm that indeed the oil psi gauge isn't lying, by hooking up a mechanical oil psi gauge and rechecking your pressures. If they change for the better, the gauge sensing unit is probably ^%&$.
If it shows no changes, try a thicker oil (higher viscosity rating) and see if the pressures improve. (thicker oil doesn't leak as fast)

P

 

well i feel pretty good about the oil pressures. reason the oil light flashes when the pressure drops below 8psi. and its right. also it has 2 qrt 10-40 and 2 qrt 20-50 so going even thicker may not do it. i'm going to a junk yard today to see what i can get.

 

thanx for all the input. a short note. I fixed it. the pick up screen was clogged like a mother. there was probably only a nickel sized spot that was not clogged with junk. oh and the junk yard didn't want the car and this motivated me to investigate. now i can sell this beast in good conscience.

 

Cool !!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dublaaciv &raquo;</TD></TR><TR><TD CLASS="quote">thanx for all the input. a short note. I fixed it. the pick up screen was clogged like a mother. there was probably only a nickel sized spot that was not clogged with junk. oh and the junk yard didn't want the car and this motivated me to investigate. now i can sell this beast in good conscience.</TD></TR></TABLE>

what was it clogged with????????????remove the valve cover see what it looks like in there ,,,if oil was rarely changed u could have a lot of mud up there , if so ,it will clog up the screen again ....