Chevrolet Repair: 99 Sub w/7.4 liter., coolant leak, gasket material

Question
I have a '99 Surbaban w/ 7.4 engine. Had a very minor coolant leak at intake/head, after the repair shop replaced the intake gasket, it now has a slight knock on startup, this goes away after a few seconds. I think that something such as old gasket material, fell onto a lifter and is restricting oil flow to the pushrod and rocker. FYI the coolant leak appeared to never get into the oil, the oil on the dipstick always looked clean. Let me know what you think
Thank-you for the help
Greg

Answer
Hello Greg, Well this problem used to be very common years ago. Some people use a die grinder with a 3m cleaning disc to remove the old gasket. This disc will leave super small partials that will pass thur the oil filter and wear the bearings in the engine. I'm not saying thats what happened to yours but it does happen. You need to use a scraper and use a towel in the lifter area to catch the stuff. You could have a bad check valve in the oil filter and it is draining out so when cold it has to fill the filter first causing the knocking noise. Replace the filter to see if this corrects the problem. The noise your hearing is from the lower end so it couldn't be a lifter problem.

Hope this helps

Have a Great Day         Mark