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Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4087
Experience:  Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
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i have a 98 gmc sierra 4x4 350 5.7- i started it up one morning

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i have a 98 gmc sierra 4x4 350 5.7- i started it up one morning an oil came spurting out from between the oil filter and the oil filter housing. the filter was a little loose so i hand tightend an tried it again but oil was still coming out. i changed the filter an added more oil but oil was still coming from the same place. the oil pressure gauge was also to the max, what might the problem be?
The oil filter adapters on these have a rubber o ring seal on the top where they seal against the block. It is pretty common for these o rings to get hard and brittle and to blow out or split and leak real bad. I have seen motors destroyed in just 4 or 5 miles of driving when they go bad because they can leak so much oil so fast as it is under pressure at that location. You may also want to be sure the oil pressure sending unit itself is not leaking. Also pretty common on them. Not hard to repair. Just buy an new o ring and gasket for the adapter, remove the filter, if it has cooler lines, unhook them, then remove the adapter. Some of them have 2 bolts inside of them that are covered by the filter. Some of them you need to remove the threaded shaft that the filter screws onto. Some have an allen shaped hole in them to install a tool, some have torex shaped and some have a flat area toward the top of the threaded pipe to get a wrench on. Just remove the adapter, clean the old o ring and gasket off, install new parts and assemble. I like to use a little Vaseline to hold the o ring in place while going back together with it. But fix it fast, don't try to drive it or it may cost you a motor. If you do not understand any part of this, drop me a note and I will try to clarify. Thanks
Customer: replied 8 years ago.
I have already taken off the oil filter housing or the oil pressure sending unit. I unhooked the cooler lines an took off the two bolts that held it up. I inspected that and it didnt seem to be damaged. The o ring also seemed to be intact. The oil comes out pretty good but seems to only be coming from between the oil filter (with lots of pressure) and the housing even with a new filter. Should i just replace the oil filter housing or the oil pressure sending unit? Another thing i should add is, the day before i was about an hour away from home and i noticed it was heating up, it was pretty late so i just kept driving while it was running hot. Im not sure that driving it while it was that hot damaged anything since it was the next morning when i had problems with this.
It sounds like you may have 2 separate problems, with the hot running and the oil leak. I doubt one caused the other. My other concern now would be how much oil pressure the thing is putting out. If the oil pressure by pass valve inside of that housing is bad, sometimes they will let way too much oil pressure develop and that will cause them to leak right past the O ring or seal on the filter. If there is a small valve in the top of the housing, see if you can push it in and out and if the spring feels like it is okay behind the small plate that looks like a valve, I guess it is even possible to the oil pump to cause this kind of a problem, but we would need to install a mechanical pressure gage to get an oil pressure reading right there where the oil sender screws into the housing. If the pressure is normal then one of those items where you are looking has to be defective. The O ring, the housing, the sending unit or one of the fittings for the cooler lines. With out being able to see it, all I can do is generalize. But they have had a lot of problems with the O rings and the cooler line fittings. You are just going to have to look them all over real close and see what you can come up with. I guess it would even be possible to the housing to warp or have a crack in it, etc. But what ever you do, don't drive it until you are 100% sure it is no longer leaking. Would hate to see bearings get wiped out for a crummy leak like that. Might pay you to invest in an O ring or two and assemble it to get a pressure reading too. If something is causing excess oil pressure, it may just keep blowing oil past the O ring or filter seal until that is taken care of. If the bypass valve is ok in the housing, that would leave the oil pressure relief valve or spring in the valve as a possible cause, that part is in the oil pump. Let me know what you find. Thanks
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