hey guys, im looking at gettin a project car but want to feel everyone out and see if maybe the problem is too much to worry about. the vehicle is a Firebird formula with a carb 305. it looses oil pressure after it warms up to normal temperature. i dont have the vehicle here, but its got 50,000 origional miles on it, supposedly always bene reliable to this point. any ideas on what the issue is? i read the other forum about losing pressure on acceleration, turned out to be a clogged oil filter. what might be the problem here? thanks guys! -chris

How do you know the oil pressure ACTUALLY goes away? Is this according to a gauge, or just according to that waving-pointer thing in the dash? Does it have the other symptoms of low oil pressure; noise, deep-black burnt-smelling oil, metal shavings in the oil, etc.?

The sending unit often fails. If it is also leaking, then it FOR SURE has failed, and its reading cannot be trusted.

But if it's a project car, then the 305 short block will no doubt be going into the trash anyway; so it's a moot point, as long as it lasts long enough to get to the engine hoist.

If the gauge is working when it's cold, it's probably working when it gets warm. If that engine is important to your plans, I'd make sure I knew what the problem was before I bought it. Low oil pressure when warm is a sign of bad bearings. I'd check to see if the oil is contaminated with anti-freeze, change to a quality filter, and if it still reads low I'd put a real pressure gauge on it.

dully noted. like i said, the car isnt here yet, going off what i was told. appearently there are no other symptoms of any problems at all, he did say the car needs a oil change, so im thinking its prolly just shitty oil and a filter thats prolly worn out by now. either way, the small block v8's are a dime a dozen, and most parts are fairly cheap considering. ill check it out good, as good as ic an anyways, but ill be sure to put a real gage on it instead of just a needle on the dash, the sending unit might be gettin ready to go out.

just get a mechanical oil pressure gauge from autozone there like $17, cheap way to see if your electronic gauge is working properly or not and if you have good oil pressure hope this helps

so after getting the car here...and climbing underneath it as well as careful looking on top, it appears the sending unit (behind the carb next to the drivers side valve cover) is actually leaking. i knwo the car has an idiot light for the oil pressure anyways, and according to the so called gage it is dropping to right before the red line for low pressure. would a leaking, or malfunctioning, sending unit be the reason it says its reading low? the light on the dash is not comming on, and no other low pressure problems (knocking, ticking etc etc) seem to be arising. just wondering what you guys might think of it.

AFAIK there is no light.

The sending unit behind the dist is for the gauge.

No doubt, since it was leaking, you replaced it. How did it work after that?

havent replaced it yet, just noticed that seems like where the oil leak is comming from (mostly), this morning, plan on checking into getting one this evening when i take my so called girlfriend to work haha ill let you know what changes on it, was just wondering if it was elaking, that could lead to a false reading at the gage. but yea, its gonna get replaced :-)

so ive replaced the sending unit (looked easier than it was). the oil leak has stopped, i no longer have a puddle of oil under my car (yaaaayyy!). also, press holds near 60 at cold idle...and between like 47 and 55 (no numbers here on the gage) at cruising RPM warm, about 30 warm idle :-) so thats all fixed! :-) thanks for your help guys.

Your description of the gauge readings sounds pretty typical now.

yup, its running better :-)