Oil Pressure

[HateMyAuto]

My oil pressure's always been a little low, I'll attribute that to the leaks I keep putting off fixing. But the other day, the gauge went to zero while I was stopped a light. If I was driving or basically giving the engine gas, the pressure would stay between the 1/4 and 1/2 mark, around where it normally is, but while idling, it would be 0. It hasn't done it since. Like I said, there are leaks, but what else could it be? Oil pressure sending unit?

[NewNann]

If the car you're talking about is your 96 it is more than likely the oil pressure sending unit. Its on the front of the block in between the oil filter and stater. My car did the same exact thing when mine took a dump. Make sure you ask for the one for WITH the gauge. Its a different unit depending on if you have a gauge or dummy light.

[Scanman88GT]

I seem to remember reading somewhere that there was a perceived customer issue with the 2.8L engines having oli pressure readings that were too low at idle. I think that GM said they considered oil pressure as low as 9 PSI as acceptable at idle for the 2.8's. Depending upon hpw many miles you have on yours, it could be excessive clearances in your rings, main crankshaft bearings or cam and connecting rod bearings.

[HateMyAuto]

It's the 96, I had to sell the 89  But I checked the specs, and the normal oil pressure at 1100 rpms is supposed to be 15 psi. Thanks for the info.

[HateMyAuto]

I just replaced the sending unit today. And everything was going fine. The oil pressure was up to the halfway mark and everything was normal. Then, as I was driving it, the oil pressure did the exact same thing, where it would drop to zero if the car was idling, but go to the 1/4 mark if the throttle was depressed. There's definitely oil in it, I just changed it, and that sensor is brand new, and worked, and I'm not seeing any major leaks on the engine(I just cleaned it). Any other insights as to what it could be? Also, what are you supposed to torque the unit down to? I tightened it  pretty well, but I didn't want to strip anything.

[rweatherford]

Either your oil pump is failing or your main or rod bearings in the engine have excessive clearances.  In other words the engine is wearing out.  There are not a lot of other options if this has been a slow continual change.  If it happened suddenly then there is something else wrong.

[HateMyAuto]

As much as I don't want it to be the oil pump, I replaced that about two years ago, I really don't want it to be because of "old age." The engine has a few more that 130,000 miles on it, and the 2.8 in my GT lasted about 190,000 before the transmission gave out. It acutally only seems to happen after the car is warmed up, and if the A/C is on. If I turn the A/C off, the pressure still drops untill the car is turned off and cools down.
I guess I need to start weighing the options of tearing my engine apart and replacing worn seals, or getting a 3400, and tearing it apart and replacing the seals. Seems kind of a no brainer...

[HateMyAuto]

I think it is the oil pump. The car started running really sluggish today, and I heard this clicking sound. My initial thought was that it was the cat the finally went bad, but the sound was comming from the oil pan. It's kinda dissappointing that I just changed my oil, and I'm about to loose it all when the pan drops.

[HateMyAuto]

Big update: My timing chain broke loose. I was driving to a friends house and the something just popped, and then the engine was making all kinds of racket. It honestly sounds like a chain being dragged over the edge of a metal plate a very high speeds. The car still runs, just really loud and really bad. It looks like I'll have to do without for at least a week because all my time is already spoken for, and I don't have eight hours to pull everything apart and just look at it.

[heavywoody]

If the chain broke, your cam is no longer moving, which means your valves have probably hit the piston tops.

Time for a 3400 swap.

[rweatherford]

If the cam wasn't moving the engine would not run....

Engine bearings dont' last very long without oil pressure.  The rods and crank are probably slapping around in there.

[Luckymc420]

Eww Yea if your Cam just stopped and your still were moving you know those pistons met some valves.  IT should of died.  But I would just got by a newer 3.4.  Fun fast and easy.

[HateMyAuto]

I'm not sure the chain itself broke, just the dampener. I'll be taking the cover off sometime this week and seeing what's going on with the chain. If the bearings are gone, and the rods and crank are loose, then I guess it is time for a 3400.

As an afterthought, assuming the chain does need to be replaced, while I have everything apart in that area, what else should I be thinking about replacing? I'm thinking seal wise, but anything really. And what kind of special tools are required, or can it be done with just wrenches and sockets?

[rweatherford]

Is the motor worth all of those parts when you can buy a running 3400 with low miles for a couple of hundred bucks?

[Luckymc420]

Well If i was you I would drop oil in clean pan. Check for crap in there.  Check your oil pump screen. (Maybe part of your oil pressure problem) Pull a bearing from crank.  Check for grooves.  Also check crank.  Same stuff on piston rods.  I would pull like maybe 3 just to make sure.  I really don't think your timing chain is the problem.  Run your car and roll under there and listen to the oil pan.

?The car still runs, just really loud and really bad.???

More details!  Loud as in muffler or chattering.  Bad Like missing?

Also as your car warms up and your oil gets hot it will drop in pressure do to heat.  Normal!