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Thread Title:

6.5 knock then goes away?

Created On Monday December 25, 2006 14:24 Diesel Talk
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Note Monday December 25, 2006 14:24 View thread in raw text format
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1996 C3500 4dr dually,4:10 rear. I pulled the original motor out and replaced with a 1994 6.5 out of a van, it has 124000 mi. This motor ran perfect till a few weeks ago. I took it to deliver a boat 650 mi away. I got about 200mi the oil pressure dropped 3psi to 41. This motor runs 195-200 around town and 210 on the highway. Came back with only the 3 psi being the only thing happening. Then I went to pass a vehicle and suddenly it started to knock, I pulled back and it stopped. It hadn't done that again. This weekend I went to deliver a motor, round trip 800mi. Ran about 400mi it suddenly dropped from 40 to 30 psi oil pressure. For about 30mi, didn't make any noise or sound like it needed oil. I pulled off a exit to get the oil changed, it was due. When I started to accelerate up the ramp it did briefly knock again. The dealer I had the oil changed at didn't find anything wrong. Got back 40psi and knocked again about 150mi later,going up hill. Only afew seconds again. What is going on? I have never had a bearing try to go bad, if it's going to spin they will.
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Note Monday July 16, 2007 06:10 View thread in raw text format
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I'm going out on a limb here but this knock happens when you accelerate under a heavy load right? To me it sounds like the egr (exaust gas recirculation)system is staying open.

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