2004 Chevy Silverado Engine knocks

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2004 CHEVROLET SILVERADO

Noises problem
2004 Chevy Silverado V8 Four Wheel Drive Automatic

My engine started making a knocking noise lately when I start it for about 20-30 seconds. Then the engine runs smoothly. It does this when the engine is cold. So if I start it then leave it for an hour or so and I start it again, I usually don't hear any knocks unless it is extremely cold. I added STP fuel and carburator cleaner for high mileage engines to my gas tank but it still knocks for the first 20-30 seconds when I start it. I was wondering if this problem could be fixed or is it a costly thing to fix. Mileage on the engine is 333000Kms. Thanks.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,708 POSTS

With that many miles, chances are the rod or main bearing are worn. As a result, you hear it when it's cold. Metal expands when it gets hot, so when that happens, the noise goes away.

A couple things you can try is to make sure that the oil filter has an anti-flowback valve. Also, use the proper weight motor oil and a high mileage oil may be helpful.

With that many miles, the engine is just wearing out. You could try having the rod and main bearing replaced, but chances are the crank is worn and you'll still get the noise soon after replacement.

If you have other questions, let me know. Also, when it is making the noise, be easy on the engine. Also, make sure you have oil pressure as soon as you start the engine. If you don't, that could be causing the noise and it could be an oil pump or a plugged pickup tube.

Joe