1998 suburban vortec knocking/ tapping

**chevysub** · 08-25-2009, 10:25 AM

I have a 1998 suburban and I just replaced the head gaskets it had alot of water and sludge in the pan and the intake valley, it started up ran great drove it on the freeway ran good oil pressure was normal 40 then all of a sudden the engine cuts off. pulled over turned it back on started to make a rattleing noise/ knock drove it and it went away but the idle is very low and the oil pressure is running about 20 then I got closer to home and it started to knock check gauges lite came pressure was very low as I was at a stop then I press the gas oil pressure goes close to 15. checked the oil and it was exteremly hot! and oil changed to a grayish color it had a little sparkle to it i think it has some metal particles, I ran 10-40 in it has about 120k on it. I looked at my rad and it has connections for a oil cooler lines and I looked at the oil filter where there should be lines and there wasn't any they had plugs on the oil filter mount, did they come this way?

could it be that I didn't adjust the rockers correctly?

**X-Hibition** · 08-28-2009, 06:23 PM

Water and sludge in the pan indicate coolant leak and limited oil and filter changes. It was probably run hot. Shiny particles are metal in the oil, that and the noise should indicate bearings have been wiped out.

I hope I'm wrong...

**digger4x4** · 12-20-2009, 11:51 AM

Ive got a '97 silverado Z71 with 138,000 miles and as of this morning have a loud knock. I just recently found out my intake gasket is leaking and was in the process of getting time to fix that but now have this problem as well. Oil pressure is still running normal but knock does not go away once the motor is up to temp. Any ideas that the leaking gasket may have caused this too?

**tbplus10** · 12-20-2009, 04:45 PM

The knocking noise could be an indication that a lower rod bearing is failing.
Water and oil dont mix well.
If you had water mixed in the oil in the pan the oil pump could pump beads of water through the lubrication system, when this happens theres a possibility of starving a bearing of oil, it only takes a second to starve the bearings.
If this is the case the repair is to either rebuild the engine, if the bearings didnt cause to much damage to the lower gallerys and bearing races, or replace the engine witha rebuilt/reman/or take out.
Use a mechanics stethescope to isolate wher exactly the knocking coming from.