Hi all - not sure if this would be the right place for this question, but im gonna give it a try since i have had excellent help from this site before. I have a Sullair 185 towable compressor with a john deere engine that is pegging the oil pressure gauge well past 125. Changed oil and filter, running the proper viscosity oil, and still has way too high oil pressure. Anyone ever had this type of problem before? I cant imagine what may be wrong, maybe stuck oil pressure relief valve? Any thoughts greatly appreciated.
What's the history on the unit and the problem? If you've verified the pressure with another gauge, then yes, the relief valve is faulty.
Yes its been verified with another gauge...over 150 lbs. Had a head done on it some time ago i believe. Unit has been running fine at several jobs. Found old oil pressure gauge in bottom just niw that looks to be blown out. That could have been the clue right there lol. Any idea wherr that valve may be- think i heard somewhere its behind the timing cover? Ugh... Probably have to PTM? Thanks for the response so quickly.
Do you know what model this JD engine is? That would help get the information. But I would have to say most engines have the pressure regulator valve either as part of the oil pump or right near by in the oil pan. Don't get me wrong there are some that have them other places but that seems to be the most common. Well just as a wild guess I looked up at least one Sullair compressor that has a John Deere in it and found that one used a 4024T. Went to the John Deere site and found the oil pressure valve in that engine is in the front cover, most likely have to pull pan to access it. It is the parts 9-12 in the picture below. Again this is only a wild guess as I have no proof what engine you have in you compressor.
Its a 4039DF.
Well I'm no expert on John Deere Parts books on line and it appears that they use "Code Numbers" to determine what parts go into what machine/engine. Anyhow using the 4039 model number it looks like that engine may have an externally accessible pressure relief valve. Below are two different front cover arrangements I found and they both look to have a plug on the front side where you can remove the relief valve.
Good work there Hansen..
Hope the original poster is able to check this out and determine why he has so much oil pressure! It is not often you hear of a complaint regarding high engine oil pressure usually it's the other way.
Great information all...thats going to help out alot. I will check out today and let you know the results. So glad i dont have to pull the motor.