No oil pressure- please advise!

[Shupe]

I recently purchased a 1994 Eagle Talon with blown a head gasket and rings. It didn't have any oil pressure, either, and I assumed that was at least partially because of the head gasket. I replaced the rings, rod bearings and gasket this past weekend, and now it seems to run beautifully, except: when I start the vehicle, the oil pressure is perfect, but after a while (with no change to the performance of the engine) the oil pressure begins to slowly drop. It will go up when I push on the gas, but after several minutes of heating up will fall to zero and not go up any further. I'm worried about running my cylinders dry and the reason that I did not replace the oil pump before is because I can't afford $160 for the pump, $14 for the gasket, and $10-$15 for the filter and oil. I found a pump out of a junk yard for $25, and I'm betting that it is the culprit, but the junk yard parts scare me and I'm not even positive that it is the reason. I have changed the oil twice already, and ran both thick and thin oils. I also tried STP Oil Treatment. Any help is very welcome!

 

[Enigma_Man]

What are you using to measure oil pressure? The stock gauge isn't really good for accurate measurement.

On my car, which has been fine like this for ~20,000 miles now, the oil pressure sensor is both sluggish and low.

When I'm idling (after the car has warmed up), the gauge will show just barely above what I'm guessing is "0", the lowest bar on the gauge. When I just start it, it might be slightly over the second bar on the gauge. When I'm driving on the highway, at 3-3.5k rpms, the gauge will read somewhere around that second bar, usually just below it.

I believe this to be because my previous engine took a dump when the oil filter backed off. The sensor is probably caked full of coked oil, and just isn't reading accurately.

That, and the sensor wire connected to the sensor has fallen off a few times, and is quite dirty, so who knows how clean that connection is.

You could replace the pump, but honestly, if you don't have money to build the motor up right, I'd leave it be until you do have the cash. Can't drive very far on fumes, so-to-speak

I don't want to say that everything is okay, just incase it isn't, but it sounds like typical DSM behavior. Just watch for that oil idiot light, you have about five seconds to shut the car off if you see it come on.

-Jesse

 

[Shupe]

I no longer have any oil pressure from the guage- My dummy light comes on when I'm idling, and when I rev the engine it goes off. It doesn't sound like there is any extra friction in the engine- something that I would assume that you'd hear if the cylinders were running dry. I found a used oil pump for $20 if I pull it myself, but I'm not so sure that it is the pump. I'm hoping you're right about it being the sensor- but I can't find an oil pressure test guage here in town to find out. I did crack open the valve cover and oil did spew as it is suppossed to... But, I'm not positive the problem is nonexistant- at least not enough to drive. Maybe I could back off the oil filter and see how much oil comes out when I try to start the engine? Any other suggestions? I'm going to call a local shop and see if I can find a test guage, but I'm not sure I'll be able to get ahold of one.

 

[Pointer]

If the light is coming on, then there is probably a problem. As for the stock oil pressure gauge, the design of the connector for the sending unit is poor at best. I have been having nothing but problems with this since my rebuild. I also have a bit of a leak down there though and the plug keeps getting covered in oil. I keep spraying it off with elctrical parts cleaner and it will work for a little bit and then i have to repeat the process. Yesterday I cleaned it all out and used some fine grit sandpaper to claen the nub on the sender and the plug itself. I then took a small screwdriver and used it to bend the connector in the plug slightly up to hopefully make a better connection. Don't know if it will work but we will see. I have plans to order an autometer gauge as soon as funds permit though. That stock gauge is just plain crap.

 

[zadir]

Originally posted by Shupe
I recently purchased a 1994 Eagle Talon with blown a head gasket and rings. It didn't have any oil pressure, either, and I assumed that was at least partially because of the head gasket. I replaced the rings, rod bearings and gasket this past weekend, and now it seems to run beautifully, except: when I start the vehicle, the oil pressure is perfect, but after a while (with no change to the performance of the engine) the oil pressure begins to slowly drop. It will go up when I push on the gas, but after several minutes of heating up will fall to zero and not go up any further. I'm worried about running my cylinders dry and the reason that I did not replace the oil pump before is because I can't afford $160 for the pump, $14 for the gasket, and $10-$15 for the filter and oil. I found a pump out of a junk yard for $25, and I'm betting that it is the culprit, but the junk yard parts scare me and I'm not even positive that it is the reason. I have changed the oil twice already, and ran both thick and thin oils. I also tried STP Oil Treatment. Any help is very welcome!

If you really didn't have any oil pressure your engine wouldn't last 2 minutes. Very Possible that your oil pressure cylinder (located down and to the front of the crank pully) is bad. I would look into it.. or possibly the connection to it is bad. It is impossible to drive a car with NO oil pressure, the engine would be destroyed in a matter of seconds.

 

[Shupe]

How can I tell if the oil pressure cylinder is bad? I'm going to clean the sensor first thing in the morning to see if it is any different. I always turn it off when the light begins to flicker, but it wouldn't run on little to no oil pressure either, would it?

 

[zadir]

Originally posted by Shupe
How can I tell if the oil pressure cylinder is bad? I'm going to clean the sensor first thing in the morning to see if it is any different. I always turn it off when the light begins to flicker, but it wouldn't run on little to no oil pressure either, would it?

I don't know how to tell by looking at it if it is bad.. A mechanic could probably test it and find out. The car would run with no oil pressure.. but it would be horrible noisy and sound like metal was hitting metal. I don't know how long an engine would last MAYBE a minute but would very highly doubt it.
Also does your check engine light ever come on?

 

[BUCK]

Before I panicked I'd pull the oil pressure relief valve cap (7/8 wrench), spring & piston at the rear of the oil filter housing & give it a good cleaning & inspection. If the piston doesn't drop out you'll have to pull the housing - (4 bolts & a couple wires). Good Luck

 

[Shupe]

I'll try to do those things tomorrow- at the moment it's dark and raining. My check engine light has been on since before the re-ringing, and it still is.