Hi guys.I have a 1988 Iroc-z 350 that has high oil pressure.I have replaced the gasket that goes between the block and where the oil cooler presses up against it and it blew out for the second time.The oil guage is pegged at the high end of the scale when the gasket blew out.Anybody else have this issue? Thanks.

 

Sounds like the bypass valve in the oil pump is stuck. (closed) No way for it to regulate the pressure that way, it just goes for broke. Usually due to debris or damage to the valve's bore.

A little history would help. Guessing at this sort of thing in an information vacuum is just abuncha ... guessing.

 

Car is all stock with 230k on it.On Wednesday the aforementioned gasket blew out and I had 4 quarts of oil all over the drive way.Got under the car and noticed the gasket was bulged out.Removed oil filter and oil cooler took out old gasket and replaced it with anew one.Started the car and the pressure was through the roof.Drove it to work about 3k away and it blew out the same place as before.Now my work has 4 quarts of oil all over the parking lot.Could this have something to do with the oil cooler being blocked or the oil bypass in the oil filter adaptor being blocked?

 

No and No. Sofa gave you the best guess.

 

.Ordered a Melling M55hv pump from Carquest. Thanks to all the replies.

 

Don't waste time with a HV pump. Is this a mechanical oil pressure gauge? Did this just suddenly start happening on a motor with 230k on it?

 

The gasket blow out is the bigger problem here it seems.

 

Was anything done with the engine before this started? Verify with mechanical gauge as factory is electrical operated through a sensor to convert to electrical value. If rest checks ok than oil pressure relief valve may be stuck closed (in oil pump).

 

Possible Sending unit failure? along with a cracked or broken oil filter adapter. Have had that happen before.

 

Stock oil pressure guage.It was fluctuating for a while then it pegged out high then it blew out.Sofakingdoms diagnosis seems to be the logical approach so we are going with that.

 

I think you didn't read the last line of his advice. Have fun.

 

Oil filter adaptor was broken in half How would that cause excessive oil pressure?

 

Replaced oil pump and later found out the oil filter adaptor was broken in half.Replaced that too at the same time and seems to be okay.Pressure is about 150 kpl (21 psi) at idle and 350kpl(50 psi) when cruising.Melling m55hv pump and 10w-30 oil.

 

Can't. A problem for sure, just, not part of THAT one.

Glad a new pump got it fixed. What did the autopsy on the old one reveal?

 

Lookes pretty clean inside but I have never had an issue with a sbc lubrication system so I do not know what I am looking for.

 

Anything that might have been blocking the relief valve piston from moving correctly in its bore, or anything that might have been blocking the valve's discharge passage. Blob of sealant for example.

 

When I get a chance to disassemble the spring and piston I will update.Thanks

 

Removed roll pin and spring but when I tried to remove the piston it got stuck about halfway down its bore and I had to force it out with a coat hanger,Could this have been the issue?

 

A relief valve piston hanging in its bore could be a problem, or THE problem.

 

See my signature for a helpful logic tidbit.

 

Makes sense.Sometimes I think I start looking too deep instead of on the surface.Thanks for the info.