XD Talk

Captain Jack · 05-12-2012, 05:14 PM

It is coming from the engine, but I am having trouble finding exactly where because it goes away shortly after starting the car and at ldle. But when it is driven, I can hear it again when I give it more gas. His oil level seems a little low, no signs of leaks either. He doesn't know anything about cars so I try to help him out whenever I can. But this one's got me stumped. The noise is in sync with the cylinders firing if that makes any sense. The enjine has over 170,000 miles on it. I appreciate the help.

GT Jon · 05-12-2012, 05:38 PM

Actually that is a helpful description. I've also heard of flexplates cracking and causing a thudding that some thought were spun bearings. Then there's lifter ticks that go away after the lifter has been pumped up with oil (pushrod actuated valves, with hydraulic lifters - not sure if the truck meets that criteria). But, the noise being in time with engine RPM is a good clue. Probably is a spun bearing, especially if the engine has been starved of oil and ran hard, or if the oil is old/fuel diluted.

TX-Kevin · 05-12-2012, 08:23 PM

Motor mounts?

OneNineZero · 05-12-2012, 08:29 PM

Some areas to look in to..Push rod, rockers or lift rod.

**Deer Slayer** · 05-12-2012, 09:18 PM

Ive had a cracked flex plate fake me out, and had me thinking there was something wrong in the engine. It was a bronco with a 302 in it I think, it was a long time ago. The main clue was it also felt like it had a driveline vibration, but it went along with engine RPM instead of vehicle speed.

There's a definite difference in sound between valve train noise, and stuff in the lower end. Deep metallic clanks are from the bottom end, and valve train usually sounds more like a couple pool balls hitting. If it's valve train, it might be worth taking the rocker covers off and looking. Usually you'll be able to tell which side of a V8 it is though, just by listening.

If it is a major internal engine problem, might as well drive it till it blows up. Unless he plans on rebuilding it, there's really no point in trying to do anything about it now. What I'd do if it were mine is keep an eye on the oil. Give it an oil change, use a really clean drain pan to catch the old oil, and look for metal flakes in it. They probably won't be magnetic, the bearings are babbitt, a lead alloy. Anything magnetic, and who knows what's clanking around in there. Make sure it stays full of oil, and change it like it should be. I've seen engines sound like they were gonna die any minute go thousands of miles before they died. You never know.

donmopar · 05-13-2012, 01:33 AM

with the miles it has on it I would quickly check on the flexplate or rockers. But a simple install of a pressure gauge on the oil will be the best test. Even if it is say the flexplate you could avoid a bigger problem if it has low oil pressure by throwing some bearings in it while you are fixing the other problem.