I have a 91 camaro rs with a 305 tbi 176k miles and it is my everyday car so it runs fine, but recently I noticed I have only a little oil pressure when I start the car after its been sitting a while... once the car heats up it says I have no oil pressure... can any one help..?

Its been running like this for a while and it seems fine but I would like to fix it.
It dose not burn much oil, only a little bit. I get oil changes every 3000 miles, is it possible my oil pump is shot, or maybe my engine is just dieing slowly....

 

If I were you I would be saving my money for an overhaul. If your oil pressure is that low your bearings are shot or will be soon. Don't wait too long, the longer you run it that way the more damage is being done which in turn means more money to build it back

 

Are you sure the gauge is working right? If your oil pressure is that low it will run like crap. Plus it would only take a day or two for the engine to blow.

 

Ehh not really. Friend of mine had bought a Blazer with a tired old 350 that would read 5 psi when warm if he was lucky. Drove it for I think about 2 years including pulling a car on a car trailer many times. Pulled that engine out before it let loose and stuffed in another 350 he built.

Br0kenxFaith, it's either going to be a sending unit, gauge, oil pickup tube, low oil level or just a pain worn out engine. Quick and easy check for the gauge is to get a mechanical one just to double check against the stocker.

 

Change the oil pressure sending unit FIRST.

Don't get all worked about oil pressure just because the gauge reads low, if the motor seems fine otherwise.

I wouldn't bother with the mechanical gauge. Think about it. You've got a car whose gauge reads low; odds are about 98% that either the sending unit is bad, or the car ACTUALLY has no oil pressure. Odds are probably 2% OR LESS that the gauge in the dash is bad. So, in the first and highest-probability scenario, you go out and spend money to buy a mechanical gauge; and you spend all kind of time and effort to put it in; and it tells you your dash gauge reads low. So, what do you do now? You go out and buy a sending unit and replace it, and now your dash gauge agrees substantially with the mech gauge. But, you ALREADY KNOW, because you've been told, that the sending unit is the piece that generally fails; so how did the mech gauge "save" you, when you could have just changed the sending unit in the first place? Did it save you any time or money at all? Or, in the other high-probability scenario, you put in the mech gauge, and discover that you REALLY DO have no oil pressure, so now you have to deal with the motor; and naturally, in the course of renewing all the old failed worn-out parts, you replace the sending unit ANYWAY, which you could just as easily have done up front; so how did spending the money, time, and effort on the mech gauge, help you in that instance? In NEITHER high-probability case, did the mech gauge accomplish anything useful; in BOTH cases, it was merely a waste of money, a delay, and a detour away from a direct attack on the problem.

Use logic and common sense, I think you'll see that the correct course of action becomes clear and self-evident.

See my signature for a guide to the mental process of troubleshooting.

Change out the sending unit and go from there.

 

Yes, make sure the gauge is working first. When I bought my 89 IROC the oil pressure was low. About the same miles as yours. I've heard it's common to these cars/engines. It kept getting lower and lower and eventually started knocking. Had to rebuild the motor. Also note that I spent as much getting the crank reground and rods resized as it would have cost to buy a cast steel stroker kit. Wish I'd stroked it. Just a thought.

 

Thanks for the help guys I will replace the sending unit first and than ill take it from there hopefully thats the problem. My car has been running fine with this oil pressure for quite some time now so I dont think my engine is gunna blow anytime soon. Lets hope not anyway.

Thanks

 

i agree with SOFA change the sending first . mine almost gave me a heart attack several times till i changed sending unit . two years later and it's still fine . this is common problem , sensor is normaly just above oil filter . be careful with the plastic on the elect. connector . gets brittle with age and heat . GOOD LUCK !!!

 

As usual Uncle Tom and Sofa are right on. Also check your grounds. If you`re not getting any lifter rattle or strange noises/ticking/knocking it sounds like nothing to worry about, most likely related to the sensor or gauge.

 

Sheesh, right a book why don't you 15 bucks for a mechanical gauge that you can use later as a tool and a few min under the hood hooking up a fitting. You make it sound like it's the end of the freakin world Maybe I just like trying to figure out what's going on instead of throwing parts at it and hoping that fixes it.

 

If you could buy a 20$ tool to avoid parts-swapping a $100 part, then buying the tool (gauge, in this case) would be the way to go.

If you could use a tool in 5 minutes to diagnose a problem (gauge) and save yourself 2 hours of parts swapping time, then yes, buying the tool would be wise.

On the other hand, buying a $40 tool to troubleshoot a $15 part, and doing several hours of work installing the tool when changing the part only takes 10 minutes, is not logical.

ESPECIALLY NOT when you already know what the results of buying the tool are going to be.... you already know it's going to tell you that you need to either swap the $15 part or replace the engine, which if you swap the $15 part, it'll either fix the problem or you'll still have to swap the engine.

There's a time and a place for serious investigation, and there's a time and a place for just jumping in and getting it done. My apologies, but I'm going to write another book to make the point.

Early in my career, I was an electronics tech. I went to work managing a group of techs, where we had dozens of these machines that would fail regularly, like clockwork. Some one of their functions would just up and stop working. Sometimes, the guys could get them back working again by turning up the sensitivity of the affected circuit; they could maybe do this to a given one a couple of times, but as sure as night following day, if they did that, it wasn't long before it failed altogether. It was 100% predictable. Put a label on the machine that said something like "turned up ckt 2 Apr 15", and by May 1 if not sooner, it was on the bench AGAIN for ckt 2.

Turns out, these things had a handful of cheep electrolytic caps, anywhere from maybe 4 to about 12, on each of about 6 circuit boards in each machine. The problem INVARIABLY was, a bad cap ($0.37). My predecessor had bought a capacitor tester ($250) to check caps with; worked great, you could test each one, and swap JUST the bad one. HUGE time saver: before that, the techs would put the bad card up on the extender, and hook up different little gizzies to simulate the signals the machines used, and probe around with a scope, and find where the siganl stopped; took a couple of hours to find ONE bad cap that way, probably 3 hours total PER INCIDENT. The cap tester "saved" ALOT of time, probably cut repair time down to about a half-hour total per failure. Everybody had thought it was a great idea at the time.

Sound anything like buying a mechanical oil pressure gauge?

Of course, what happened was, next week, the machine they had just fixed,would just fail again, and production would stop while somebody changed it out (they kept spares on the shelf), and one of the techs would check through all the caps and find the bad ONE and change it out, and put it back on the shelf as a spare. Then eventually it would rotate into service, and it would go through the whole cycle again (sometimes the spares would even come off the shelf and be bad when installed).

I took ONE LOOK at that, and said this is BS.... ordered enough of some super-expensive HIGH QUALITY electrolytic caps ($0.78 each or something) to replace EVERY SINGLE ONE in the entire plant. Probably spent $800 on caps (had to argue endlessly with my boss about the expense, but eventually I played the one "new guy" card I had left, and got my way, just this once). I had the techs go through EVERY SINGLE machine and swap out EVERY SINGLE cap, and miraculously, the problem STOPPED COLD. No more lost production AT ALL (turned out, apart from the caps, the machines were PRETTY DAMN RELIABE!! nobody ever knew that, they all thought the machines were POSs because they had broke all the time), no more PO'ed managers above us, no more frantic desperate calls in the middle of the night, no more unused spare machines sitting on the shelf (we put them ALL into production and increased capacity and thereby made more money). And best of all for ME, we saved SO MUCH time, that when one of the techs quit, I didn't have to replace him. In fact, I was even able to give the other techs bigger raises, because (a) the money was in the budget already, (b) the operation was more profitable, (c) the techs were doing USEFUL stuff instead of dinking around checking caps, and best of all, (d) all of this dissatisfaction pressure from upper management about the machines breaking all the time and causing production quotas to be missed, was GONE.

So here's the bottom line. Was buying that $250 capacitor tester to test $0.37 capacitors, every one of which fails every couple of months, wasting hundred of hours of the techs' time every month, losing a couple thousand dollars of production every time a cap failed, and keeping extra people on the payroll just to work the cap tester, a good idea? Or, was spending $800 ONCE, to just "shotgun" every cap in every machine whether it was bad or not (blind parts swapping) better?

Moral of the story: always look carefully at the TOTAL cost of the operation. There's a time and a place for jumping in and JUST SWAPPING THE PART.

Please excuse the book.