Hugh_Mann

Hey all, I have a 1991 3.0 V6, 4wd, 5spd Pickup with 265,000mi that has a loud clanking or rattling sound which matches the RPM's of the engine. It's only present while in gear and mostly in 1st and 2nd. With a cool engine it's at it's loudest and quiets down but doesn't disappear when hot. At highway speeds in 4th or 5th gear you don't hear it at all. Power seems decent and I get about 20 mpg on the highway.

I've raced it in neutral on my driveway and there's no clanking, just the usual valve/injector ticking. It's tough to pinpoint when you're driving but it's coming from the engine bay.

Thanks for your input.

xcfunrunner

Well, it is obviously something to do with your powertrain. Have you checked the Center Support Bearing? I believe extended cab pickups have it. Not a regular cab though. It will be on the driveshaft, halfway down. It will split the drive shaft into two pieces. I would check that. Sometimes things wear out and break. Especially at 265,000 miles. Other than that, see if you can get it up on a lift and run it to try to pinpoint the noise. Is there any sort of vibrations in the stick?

Hugh_Mann

So I had a closer listen today and it's less pronounced but present when blipping the throttle in neutral. It's definitely coming from the bottom end. I'll try to get some audio if I have the time.

If this is a shot connecting rod bearing, will I have low oil pressure? From what I've seen my pressure is normal. I've heard a wrist pin could also make a noise like this. Possibility?