4.3 vortec sounds like a diesel
 

New to the forum but not to the Blazer. I have a 2002 Blazer 4x4 with the 4.3 and 206k miles I bought recently that was not running. Had alot of coolant in the oil so of course I suspected head gasket. After I took the plugs out and saw they were clean with no oil or coolant, did a compression test on 5 of the 6 cylinders (cylinder 3 was too hard to get the hose into) and all was fine. Figured it was the LIM gasket so I replaced it, and it was bad, real bad. A time consuming but relatively easy job. Set the engine to TDC and put the distributor in. It looked just a hair off, like an 1/8 of an inch from the 6 on the distributor, but couldn't seem to get it any closer. Put it back in, started the car and now it sounds like a diesel. Runs and drives and idles Ok, but sounds like crap. Could that 1/8 of an inch make the difference? There is some upper lifter noise as well. Oil pressure is good, but seems to go down if I rev it above 3k RPM. Any ideas?

Alot of coolant in the oil=done motor,especially if run for any more than 100mi in that condition. And,yes the slight mis-alignment of the distributor is evident,but if an oil pressure drop is noted at speed:motor is toast...Sorry

Test the pressure on Cylinder #3. I'm going to guess its low to none.

Any check engine lights on?

Actually since I posted this I drove the cra a bit and the engine froze. No more detective work needed. i need a new engine which i am looking for now.