oil pressure drops in drive

I was just wondering if anyone else has had symptoms like this, after my 95 sc has been driven for a while, when I pull up to lights and its sitting in drive idling the oil pressure drops , check engine light comes on and the car wants to die, usually if I put it in nuetral it will stay up a little longer before the pressure drops, but after a while it drops too, it has actually shut off a couple times when the oil pressure drops, so if any one has any advice about this problem it would be greatly appreciated. thanks

is the engine stalling ?

because thats whats been going on with mine.. then the engine started making noise.


Oil pump all the way I believe.

What kind of oil pressure gauge do you have? The stock unit is more like an idiot gauge. Basically as long as pressure is above 5psi the needle will read in the "NORM" range. Its position in that range has no correlation with your actual oil pressure. Is your gauge actually dropping to the red zone?

It's probably the slip on connector on the sensor. They get loose and intermittently loose contact. I had to replace mine with an eyelet and a nut.

I am going off the stock gauge but the engine bogs down and sometimes wants to or does shut off, I have been told that it is probally the oil pump and probally be a good idea to change the rod bearings while its all apart, but I have also been told that it might be a bent rod, but I dont know if I believe the rod could be bent, any Ideas of what could be wrong ?

Put a real oil pressure gauge on there first to verify what exactly it is doing before you tear your engine apart. As I said before the stock gauge cannot be used as you would an actual pressure gauge. Also do as Mike said and check the connector on the sending unit on the engine. These have been known to become loose with age and cause issues with the gauge.

My auto used to do that to. It stopped doing that when I replaced my negative battery cable. I guess it was a bad ground. Sometimes the car would refuse to start also.

Now sometimes when I shift from N or P into R it stalls out. I don't know why it does that. If I have my foot just slightly on the gas its fine so thats how I usually drive anyways. I have a little stereo system in my car now with 2 10's and a small amp and I can sit at a red light for a few minutes in D with my foot on the brake and the lights don't dim and the oil pressure gauge doesn't drop. I think mine was all due to a bad ground.

Like Kevin said that gauge has no accuracy. If your engine loses oil pressure, it will start to knock, believe me as I've ran an engine out of oil before and it sounded horrible.

I have noticed that when I drive the car after a while, if I get on it a little bit , when I let off the gas I hear knocking, could this be the bearings causing it , or is it worse than that ?

Thunderburd -

No.




you are probably going through the same problem I am going through right now.


If something was broken it would be making noise all of the time. No fluctuation.


It is more than likely the oil pump. You get driving, the pump decides to quit. makes sense to lose oil pressure when stepping on it if youre pump is broke. The sound you hear is valve clatter. or lifters taking on air.

change oil pump. im going through the same thing this week man. lol it sucks.

the knocking is after I let off the gas or when it revs up before it shifts gears, but the oil pressure is high at that point, it drops pressure in idle and tries to die, but it doesnt knock at that point, does anyone know if it is that hard to change the oil pump on the 95 sc's ??

What kind of oil filter do you have on your car?

I only ask because there are a couple of brands (Fram being one of them)that the diaphram will break and block oil flow. I had very similar issues as you and after I changed the oil filter all was good again.

Lotsa good ideas being thrown out there. I do have to vote for bad rod bearings though since it sounds exactly like the conditions I had on a different vehicle. The key is when you say it does it after you rev it and let off the throttle - right there is where it made the noise. It would also make the noise when I started it, because it would have the same pattern (rev, then let off).

The oil pressure would go to near-zero when it was completely warmed up.

I pulled the pan off, and the rod bearings were terrible - most down to copper. In my case it was so bad (PO ran it out of oil once) I had to have the crank reground and use undersized rod bearings. Everything else was fine, and that did the trick. I hope it's something else for you though, cuz that was a lot of work

well my mechanic has looked at it and said that he can replace the oil pump and take care of the oil pressure and to take care of the knocking he could replace the bearings but he said something like if the bearings dont agree with something else , I think he said the crank, then I might have to replace them again in about 10,000 miles, or rebuild the motor, has anyone ever heard of that, or ever had that problem ? and if so could I replace the bearings and all from the underside of the car ? he also said the rings could be bad now, does that sound correct ? or is he just getting ahead of himself ?

Yes he is. but first things first.


oil pressure is either on or off. on if over 5 psi pressure.


its an "idiot gauge".


Like I have said, if it is a problem with your oiling, you might get engine noise for a bit, like valve clatter, once it is dropping pressure. It might not be the rod bearings. Just depends on what you noticed first. Just dont run it anymore right now, obviously. Does it make the sound consistantly ?


start backwards, change the oil get a stock motorcraft filter, ( to see if its the diaphram collapsing ) then try that out, idle it ( dont go nuts on revs, but as soon as you hear anything, shut her down ) Then change the oil pump. The oil pump is external, its not that hard to get to i guess if you are determined.

If changing the oil pump/oil/filter doesnt help. Then youre screwed.

But hopefully the noise you are reffering too is just temporary, due to parts not getting oil.

Good luck.

I am having a similar issue with my 95. The oil pressure guage has always read very low ever since I got the car, but we used a different pressure guage and the pressure was good. The engine sounds normal--no knocking or valve noise going on at any time. But recently, The guage will suddenly drop to the position it is in when the car is off for just a second, and the CE light comes on. The engine also wants to stall when that happens. Is the stalling something that is triggered by the guage itself reading so low, or is it triggered by something else? when it happened I gave it a quick tap on the gas and it came back up fine with no strange noises at all. I have an aftermarket oil pressure guage that I am going to install in a pillar pod anyways, but in the meantime, I guess the electrical connection is the first thing to check?

oh, also, the car did this when I was turning left, if that helps anyone. It has only done it a few times, and it normally does it when I turn left. Any thoughts?

EDIT--yeah, the oil pump is externally mounted on the timing chain cover. If you swap this out, be sure to check out the pressure regulator that fits inside the timing chain cover as well. The books say to drill it and ise a slide hammer to pull it out and then tap the new one in. Better to do it once than have to tear it all back down again. Set aside some time though--you will have to take off the oil cooler too, and they also say to drop the pan and check out the oil pickup too.

Agreed with what was said above. TO recap:

1- dont go by your stock gauge, check with an aftermarket gauge
2- if you need to start replacing stuff do:
a- oil change (w/ good filter),
b- oil pump (or you could take the entire timing cover off, if you do dont forget there's an allen screw all the way at the bottom near the pump that is easily missed). If you replace the pump get a 94-95 pump which also fits, but flows more oil. With regards to the oil pressure release valve, check to see if the spring moves freely...if it does dont bother changin it. Its a real pain and if not installed right can cause more damage than good. This would also be a good time to at least upgrade the oil pressure sensor to make your stock gauge actually functional. There's an article on how to do this, its real easy.
3- if this doesnt fix and you really have rod knocking you really should not drive the car any longer as you can be damaging your crank beyond repair.

Good luck!

Oil pressure sensor or sending unit? Which one needs replaced to make the guage work right?