Engine Knocking!!! Please Help!!!!

I own a 1993 GMC Sierra 1500 2WD 5.7 350 V-8. Brought truck to repair shop to have rear main seal fixed and the intake manifold gaskets replaced. When I got the truck back I had a real bad knocking sound coming from my engine.

Next I had the oil pump replaced along with a new oil pan gasket and had the main bearings replaced hoping to fix the knocking. STILL NO LUCK!!! The truck has low oil pressure now for some reason and runs a little hotter than usual. Somebody please help. I'm running out of patience and money!!

I am sorry to be the one to tell you this but, Your motor is done. You tried to just put in new mains and sometimes that will give you another 20k. But in this case it did not work out for you. Sorry for that. Luckily the 350 chevy is a readily available motor and you should be able to pick up a good used motor for a reasonable price.

The low oil pressure is caused by excessive wear between the bearings and journals. As you found out replacing an oil pump will rarely fix a low oil pressure problem as the oil pump is the most well lubricated part of the engine and rarely fails, and when it does the lack of oil going to the rest of the engine causes other damage anyhow.

Best of luck,
Nate

by the way this forum is for toyota trucks you may have more luck in the Chevy/GMC forum

The thing is.... the truck runs good. It still has lots of power. If you say my motor is done, how long do you think I might have and are there any possible alternate solutions than a new motor?? I'm only 19 years old and not in a position to buy a new motor.

What I really cant understand is why the knocking started after the repairs. The truck ran like a sewing machine when I brought it there. My oil pressure was fine also. Its just been a really bad situation. I mean, these guys replaced the rear main seal and some intake manifold gaskets, which are not MAJOR repairs. I was losing oil and coolant and thats why I had it done. I don't understand were things went wrong. The truck has 177,000 miles on it. Thanks for your help.

Stephen

The repairs had nothing to do with it, things break down at odd times
on used and new vehicles. It sounds like you have a rod knocking problem, in that case you sould have bought a whole crank kit and that would have replaced the rod bearings, but with that kind of miles it may not last that long. What you need is a complete overhaul with the block bored or honed. It is up to to what the machine shop say's
and to check it out for you. They will get the engine back to like new.

Elliot