Infinite oil pressure

[DocDirk]

Two days ago when nearing home after a drive my oil pressure gauge moved to the right side off the scale. It normally runs about 50# until warmup then it's usually 30-40# at idle, 40-50 at speed. I presume this means a potential blockage in the system? The engine was running happily at 185 degrees and didn't change temp. The gauge needle returns to zero smoothly at shutoff and moves smoothly up the gauge and past the end upon startup. The pressure sender's positioned at the top rear of the block in the side of a fitting which ends an oil line that runs from the left front of the block up to the top rear. I replaced the oil filter in case it was failing to flow but nothing changed.

Any ideas on the best first place to check for a diagnosis?

Thanks in advance!

Dirk

[Got the Bug]

Dirk,

If you can, try measuring the oil pressure right at the block with another pressure gauge.

[FWB]

you need to verify if the guage or sender is working properly. with the guage pegging the needle that would mean way over 100 psi. are there oil leaks?
get some cheapo guage at the auto pats store and install it temporarily under the hood to verify. make sure the wire on your existing sender isn't worn through and grounding itself that would cause the guage to go to its max reading.

Fred

[DocDirk]

Thanks for clarification of a most reasonable way to solve a problem; first determine if the information signals a serious problem or is false information.... I'll check it out tonight and post an answer.

Dirk

[Mdman352]

So, how did you cure the over heating issue?
David

[DocDirk]

Overheating has been improved with multiple system burpings as Tom Wells has so aptly emphasized, it still runs about 200 on a warm day so I'm going to go ahead and install the front shrouding and high CFM fan. I guess any amount of air in the system begets problems in cooling.

Regards!

Dirk

[RICK LAKE]

DocDirk If the guage has an electric sender to the gauge it is possible that the line as rubbed on a metal spot and cause the gauge to pin with contact to a ground source. Did you hear any rocker arm noise? Is the oil filter shape expanded? At about 140 psi most filter blow apart. Been there done that. If you are running a plastic tube to the oil gauge in the dash, then you have a problem with either the pressure relief spring or a clogged oil filter. Try to figure out which one you have first. We can then work this problem out. You may need a new sender in the block. Rick L. If you can get to the sender wire, turn on the ignition, without the motor running and see if the gauge jumps, if yes wiring issue. Turn key off and unhook wire from sender. Make sure gauge is at "0" reading, Touch wire to sender terminal and see if gauge moves, may or may not. Ground this wire to chassic and gauge should pin to max. If this checks out OK, I would buy a sender and replace. Make sure it MATCHES the GAUGE for the correct OHMS reading. IF not you will have some goofy readings. Is it an Autometer? They have a couple of different senders. Look for numbers on the sender to match up. Good Luck Rick.

[mikeforte]

Hi,
If the pressure reading is correct it is the oil pump relief valve being stuck. Either replace the pump or disassemble it and clean it but be sure the relief valve moves freely.
DO NOT drive it until it's fixed. I've seen filters burst...... That's a BIG mess and tow job.

[DocDirk]

I bought a mechanical pressure sender and gauge today to test the oil pressure and found a nice smooth stable rise to a startup pressure of 72# of oil pressure cold. I guess I panicked, thanks to all the cool heads here who kept me on track to the simplest solution!

Regards,

Dirk

[FWB]

did you find what the culprit is.....sender, gauge or wire?

[DocDirk]

The pressure is fine with a mechanical unit and I've been scolded before this for using an electrical sender but that's what came with the kit. I'm going to replace the electrical pressure gauge and sensor with a mechanical one that actually fits into my dash.

Tomorrow I get to calibrate my programmable speedometer so it stops telling me I'm travelling at 10 mph max lol...found the instructions online.

Dirk

[FWB]

don't be so hard on the electric sender, i have a stewart\warner thats a few years old and works flawlessly. although i have a pet peeve with a capillary tube filled with oil under pressure running into the interior of a car. i had put on in a car and well, it sprayed under the dash, a mess i would not like to repeat. dirk it may be just a wire rubbing, check into it further

[DocDirk]

Fred,

The wiring is brand new on my car and it traces back from the sender to the gauge with the only narrowing being a grommetted 1/2" hole in my firewall. Connections are clean and the wire has no wear spots on it that I can see.

I'd never like to see oil behind my dash either now that I think of it. I'll order a VDO sensor replacement from JEGS.

Thanks again, you're most kind to this cobrabuilderwannabee

Dirk

[Got the Bug]

Originally Posted by DocDirk

Fred,

The wiring is brand new on my car and it traces back from the sender to the gauge with the only narrowing being a grommetted 1/2" hole in my firewall. Connections are clean and the wire has no wear spots on it that I can see.

I'd never like to see oil behind my dash either now that I think of it. I'll order a VDO sensor replacement from JEGS.

Thanks again, you're most kind to this cobrabuilderwannabee

Dirk

The chances of a oil pressure hose failure are pretty low, especially if you use an AN line. The set-up you had was accurate, so it seems like a quick fix to try replacing the sender. Sounds like you're working the bugs out just in time for the prime driving season.