It's a hydraulic roller in my Dad's Denali (1999 Model 350), every 3rd time or so when he drives it one lifter ticks. My question is, will just the lifter be bad or can I expect the cam to be done as, well?
I'm pretty sure it's a lifter, I checked it with a stethoscope in the winter and it was louder on the exhaust side. It wasn't very deep sounding, I could be wrong though. Is there a way to check the piston without opening the engine up?
What has me scratching my head is the way it comes and goes. Maybe the next time I have it ticking I'll lift the valve cover off, and look for a rocker not in full motion.
My 5.3L Suburban rattles like a deisel when cold--same thing my 94 Astro did. GM had a bulletin on the Astro about using a particular oil & filter combo. I just take it real easy for the first few miles--It has 152,000+ now, and last week it got almost 15 mpg (14.87) towing the Dart to Famoso!
OK, with some more investigating, I've now found it's using coolant and the oil pressure gauge drops off to 0 at idle when you can hear the ticking lifter. The ticking lifter still comes and goes hot or cold. The oil pressure goes up and down on it's own at idle and does respond with the throttle, it seems normal when driving. I'm assuming the engine is done with the coolant being lost somewhere, but I could not find any coolant after draining the oil, nor does it leave puddles (no noticeable smell or smoke from the tail pipe). I will see how quick it uses up coolant. It also sounds like it has a miss at the exhaust.
The intake gaskets are notorious for leaking on these engines. That plastic intake after time would move and loose seal. You need have the intake gaskets changed and that will solve the coolant leak.
I would have the sending unit checked and gauge to be sure you are getting an accurate pressure reading down low.
Lifter problem may be some carbon or dirt that gets stuck. Put some very light oil 0-10 or 0-15W in the engine and let it run for about 20 minutes in the driveway. Drop the oil and put what you usually run in the engine. "Flushing" the oiling system with light weight oil has worked for a few friends of mine.