3.9 rattle

[kahn]

I have a 1996 Dakota with the 3.9 and it has 115,000 miles on it. I bought it a few months ago and it has a loud rattle in the motor that will just drive a person crazy. It runs perfect though. I was told that 3.9's eat up timing chains and sometimes have bad tensioners, and as far as I know it has never had a new one. Do you guys think that it sounds like the timing?

[BleedDodge]

They don't even have tensioners, that's why they make the sound. They do make a tensioner kit now for this problem, but it's a sickening job to install it. That's what it is. Sometimes my 3.9 backfires. Even though the chain doesn't jump a tooth, even being that loose can cause it to have bad timing at certain revs I guess. This doesn't help fuel mileage much either.

[joecook]

ALso sometimes the rattleing can be a heat extanger on your sxhaust manifult that is rusty and just flops around check it out

[kahn]

Hey all,

Just this last weekend, I pulled my timing chain and gears out and replaced them. I was about a 1/16 of an inch from jumping a tooth! Anyways, I threw it back together, fired it up, and it sounds like a new truck. Thanks,

[A_BRO]

Originally Posted by BleedDodge

They don't even have tensioners, that's why they make the sound. They do make a tensioner kit now for this problem, but it's a sickening job to install it. That's what it is. Sometimes my 3.9 backfires. Even though the chain doesn't jump a tooth, even being that loose can cause it to have bad timing at certain revs I guess. This doesn't help fuel mileage much either.

My '92 3.9 also backfires at certain revs (1700-2000 rpm usually). The motor has 252,000 miles on it and the biggest repair that has ever been done to it was a new fan clutch. No leaks, and it doesn't burn any oil. Up till now I was stumped about the backfiring but i will look into my timing chain. Thanks.