I have a '89 chevy suburban with over 200,000 miles on it.The engine isclean and everything runs great except for this tapping.

About 2 months ago the engine started tapping, I changed the oil and it went away.
(I change the oil on the truck every 3000 miles.) Now the tap is back and its not at the 3000 mile mark yet.

It only occasionally taps, not a constant tapping. Sometimes it taps on start up then goes away after a few minutes.
Other times I can be sitting at a traffic light and it will start tapping then go away.

I usually use 10W30 oil. Last week when the tap came back I switched to a synthetic blend of oil. Now the oil pressure is down a bit and the tap is back. Should I go back to 10W30 dino oil or what?

Anyone have any suggestions on what I should do and what this problem could be?

Larry

 

Without actually hearing the noise it's hard to say, but it sounds like a lifter tap. It's not uncommon for a lifter to tap on start up and then quit after the oil gets circulated. I would think the switch to synthetic would help, if not eliminate the lifter tapping, but it may actually just need to be tightened.