Oil Pressure....Help!!

[Hognose]

Had my car out yesterday, all was well.
Took it out this evening for good long cruise and I noticed that my oil pressure is very low now. At idle it drops to 0 and cruising it is at about 15. It will not go any higher than 20!

What could this be. Any suggestions would be great, thanks!

Matthew

 

[turbofabricator]

That's usually not a good sign. Probably bad bearings. BUT did you check the oil level? Might be very low. What oil do you run? Try some 20w-50 and watch your gauge. If the oil change to 20w-50 doesn't help bring the pressure up to 50 at cruize (hot), then time to pull the oil pan and check things out. Might have a blown head gasket that then clogged the pick-yp screen. If the head gaskets have ever failed in the past, and the oil pan wasn't removed and the pick-up screen cleaned, then you may have some real bad bearings on your hands. IF the bearings are bad, but the crank is still good, you can just replace the bearings and keep driving it. One other thing to check before pulling the oilpan is the oil pressure relief valve. It might be stuck open. It is accessable by reomoving the 1" bolt next to the oil filter. Just unscrew it and pull the spring out. If the spring sticks out of the housing more than a 1/4", then the valve might be stuck open. Pull the valve out of the housing and inspect everyting closely. Here's what it looks like:

 

[Jerryl]

Good advice as usual from TurboFabricator.

What type of gauge do you have? Electrical?

 

[BlackBandit]

I wouldn't put 20w-50 in it. If your pressure just went south and you put heavier oil in it without changing anything you're probably just going to starve the bearings even more. At least if its something other than worn bearings anyway. (pickup screen, relief valve, ect.) I have a hard time believing your bearings went south in one day without any other indicators. I would pull the pan and look for problems before I ran it anymore and see what there is to see.

 

[Hognose]

I run 20-50 in it already. I had just change mt oil last week. This is a new motor with less than 2k on it. So I am hopeing the everything is ok. My oils still look very clean. I see no metalic coloration in it at all. (Yes I did check it out on the road as soon as I notice the fluctuation on the guage.

The guage is electric. (VDO) I guess I am going to go and buy a cheap guage tomorrow to see if that is the probelm.

We had gone out to eat tonight, when we got to the restaurant and pulled up when I put the car in park, that is when I first noticed the oil pressure. When we got reay to leave and I started the car back up the pressure was higher but the pressure was bounceing up and down quite a bit. Once the car warmed up it had dropped down to the afore mentioned problem.

Just thought I would mention that.

Thanks for the advice.

Matthew

The 1" Bolt, how tight should that be tightened back up?
Thanks for the advice on that I will try that tomorow.

 

[BlackBandit]

Definitely check your pickup. (after the gauge and stuff) Lot's of stuff can get in there after a rebuild. Timing chain tensioner material, rtv, could be loose...lots of options. I've never torqued that nut to a spec. I've always just tightened it down. (not he-man syle ) It's probably better to torque it but I've never had a problem. HTH james

 

[Blakboost]

This same thing happened to me at the track a few years back. It spun the cam bearings and some main bearings (nasty). Whoever built my motor last did not torque or put loc tite on the 1/4-20 bolts holding the oil pickup tube in the block inside the oil pan. It was sucking air and losing pressure. I would check that as well before running the car again. It's a lot easier to pull the pan down and check this before pulling the whole motor out HTH

 

[Hognose]

Ok this am I started the car to see how the oil pressure was when cold. Way up over 60 just like normal. It was warming up and I look down and see that my wire to the Oil Pressure sending unit was a little cooked. (bare wire) So I and very happy and cut out the bad and put a new connection on.
Fired the car back up and let it warm up. All looks well. Rev the motor and it sounds perfect.
So I took it for a little spin. Under very slight acceleartion (no boost) I am getting knock retard. And after the oil warmed up more the pressure went to the same thing. Very little, however it would raise when I reved the engine slightly.

AGain in neutral the engine sounds perfect even when reved. I am afraid things are looking good for me.

I did remove the 1'plug. The spring was resting almost an inch out. How do I get the other piece out to inspect it? Thanks

Matthew

 

[BlackBandit]

You should be able to get in there with a small wooden dowel or a screwdriver (don't scratch anything) and see if you can move it in/out some.

 

[kellyd]

I would get a mechanical gauge on it right away. My first gauge was a VDO electric and it was 20# off. HTH

Dave