high oil pressure

[juggernaut2874]

I have a 94XLT 4.0 2WD. Yesterday I noticed my oil pressure was maxed smelled burning oil so I looked under the hood to inspect. I noticed that the high pressure actually popped the PCV valve out of the valve cover. Replaced the PCV valve with a new one. I also recently changed the oil (5W-30) and filter (Fram) so I thought I might have a bad relief valve in the filter. Replaced the filter with a Purolator. Truck still has high oil pressure and will pop the PCV valve out if I get on the gas.
I'm guessing the oil pump, sending unit, or a clogged oil port inside somewhere. The engine is not dirty and covered in sludge but I guess I"ll run some B-12 or Motor Flush in the oil for a while and see if it dislodges anything.
Anyone have any ideas or run into a similar problem with high oil pressure?

 

[Maniak]

How do you know you have high oil pressure? If you haven't modified your gauge and replaced your sending unit with a different style (one from a mid 70's ford) then your gauge only has two settings. Stock, it will read 0 when there is < 6psi and it will read in the center when there is over 6psi. If it is reading over that then the gauge is bad (when you short the stock oil pressure sending unit wire the gauge should read in the center).

There is no oil pressure at the PCV. If anything, engine blowby is there. If you have enough blow by to pop the PCV you must have a bad ring or possible head (combustion gas entering the valve cover area).

Hopefully some other people will have other ideas but I don't think the oil pressure is it.

~Mark

 

[codeman200]

i'm no expert, but maybe you put too much oil in.

 

[BrooklynBay]

Check the vacuum line going to the modulator for leaking ATF. Maybe the fluid is leaking into the vacuum system, and it loosened this part. I've never heard of the PCV valve popping off. Unscrew the port where the sending unit is, and connect an oil pressure test gauge.

 

[juggernaut2874]

I do have an aftermarket gauge setup reading 30 psi at idle and around 60 psi when I step on the gas and get the RPMs over 2K. I have the correct oil amount too. I probably have two seperate problems with high oil pressure and blowby popping the PCV valve. I'm more concerned with the excessive blowby. When I unscrew the oil cap after it has been running at normal operating temp, I get an unusual amount of blowby gases escaping. If it were a bad ring or head wouldn't I be losing oil or blowing smoke (white or blue) out the tailpipe (I'm not)?
I've never had this kinda problem before so I'm stumped.

 

[bjorkmae]

Sounds more likely to be a bad ring/piston, but yes it could be a bad head/head gasket. Either way its most likely time for a new engine as even with a compression test and visual inspection and removal of the head you can't necessarily guarantee that the head is fine unless you get it professionally checked, its hard to necessarily determine a head gasket is bad upon tear down and inspection, piston ring/piston damage is easy to visually see but requires removal of the piston. Its often a lot less work and money just to replace the engine.

 

[rudypoochris]

How do you know you have high oil pressure? If you haven't modified your gauge and replaced your sending unit with a different style (one from a mid 70's ford) then your gauge only has two settings. Stock, it will read 0 when there is < 6psi and it will read in the center when there is over 6psi. If it is reading over that then the gauge is bad (when you short the stock oil pressure sending unit wire the gauge should read in the center).

Is this always true? For the longest time I have been bugged by this in my 1992 Ford Explorer. The guage used to read around the A or the L in normal. Now it reads between the N and the R, much lower on the spectrum. Recently it has even gone below the N. I replaced the sending unit, same issue. I replaced the guage with one from the junkyard, same issue. If it really is on or off then I don't understand the indescrepencies. Sometimes I can get the guage to crawl back from below N to R by flooring it at relatively high RPMs and high load. Any help on this one would be great.

EDIT: How does one short out the 1 wire sensor to test where it puts the guage? Simply touch it to the car (Negative?)

 

[juggernaut2874]

Turned out to be a bad ring and cracked piston head. Installed an engine from a junkyard with less miles than mine and it is running just fine.

 

[BrooklynBay]

Thanks for the update!