2001 silverado motor problems

M

Matt Williams

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#1
I have a 2001 chevy silverado 4.8L v8 with 128k miles. Ive had the pan dropped and cleaned out and the engine flushed and keep the oil changed on a more than regular basis, the truck smokes a little when i first start it but it clears after a couple minutes. For the first 15 to 20 minutes everything is ok but after the truck gets hot the oil pressure drops to 20lbs. also there has been a knock in the motor for the last 40k miles. Id appreciate any help or advice.

Thanks
Matt
 

Jim Davis

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#2
The smoke on startup sounds like valve seals. The low oil pressure and knock sounds like worn bearings. If it was just low oil pressure would suspect oil pump first. Dont know of any specific problems on this engine, but sounds like time to pull the oil pan again and check the main an rod bearings.
 

Transman

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#3
Just an add here, My '93 has smoked on startup form the day I bought it (brand new). I never lose any oil between changes and I have 169k on it now. The oil pressure may be a problem but the first step is to confirm the oil pressure with a mechanical gauge. The knock has been a ongoing problem with GM engines of that vintage also from the factory and may not be a serious problem. After you confirm the oil pressure falloff (may be a bad sender or gauge). Then you can determine what course of action to take next. Good Luck, Transman
 

Jim Davis

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#4
hmmmph, goes to show my brain is not always functioning....checked the oil press manually on a car last week and this is one of the simple steps I forgot to mention to do. ::)
 

Transman

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#5
LOL! We all do it, mostly because we are not standing in front of the vehicle. Some things we just do without thinking and its nice there are many heads here to help when we do forget or to add a different slant. Transman