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92 Suburban Oil Pressure/Engine Power

I have a 1992 C1500 Suburban (4x2) with a 350 TBI engine. Has about

250k miles on it but well maintained. 3 year old tranny.

My Question:

Been having cooling problems. Found out radiator was plugged and over

50% was not flowing. Bottom half of rad was COLD while the top half would burn you. Replaced the rad. NO evidence of blown head gasket. Oil looks good, coolant looks good. No knocks or pings.

After about 30 minutes of driving, the oil pressure drops to almost dangerous levels and there is a significant loss of engine power. Where the truck could make a hill with 20% throttle in OverDrive it would now take 50% throttle in 3rd gear if hot. MIL is not on. Any ideas?

Reply to
boiterjj
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Reply to
Shep

Okay but would that constitute the loss of power? The power loss I'm thinking may be a plugged cat. But am I wrong? Would crapped out mains cause oil pressure drop AND loss of power?

Reply to
JB in SC

Sounds like when the oil gets warm it thins out. I would guess that the main and rod bearings are worn to a point of causing this to happen.

Reply to
Chevy Man

Does the temp gauge now indicate acceptable temperature? First I would definitely check that oil pressure with another gauge. Since the engine has 250k miles on it it could simply be worn bearings and / oil pump, and hence the entire engine may need rebuilt before spending any money trying to find / correct the power loss.. Depending on how old the catalytic converter is I think that is a possible cause of the power loss and many exhaust shops will check that for free anyway.

Reply to
James Goforth

Reply to
Shep

Yeah the temp gauge is fine now. Temperature never exceeds 205. Mechanical gauge is more accurate (electric one jumped a lot with RPMs). Only low pressure at idle (5-10psi). Normal driving puts it around 20-30psi when hot (50-60 cold) which I know can be low but like we've already established, it's got some wear on it. But I do notice the power loss when this lower pressure occurs. I plan on replacing/ rebuilding the engine early next year but I'd like to think I can at least make it through the winter. Thanks for the help and any other suggestions you may have.

Reply to
JB in SC

Did you not read the replies to your first post of this question?

Reply to
Mike Marlow

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