4.0L timing chain ?

jeepunlimited · 07-28-2007, 08:25 PM

hey guys, i had my jeep running in the driveway and well....i herd 2 noises under the hood that could be herd over the engine running, the common wrist pin knock which its had forever, and a new noise, almost like a grinding noise, it sounds louder underneath the jeep and its near the front of the motor, sounds closest to the #1, 2 and 3 pistons !!!...im afraid it could be the timing chain ?? but i have no way to check , i tried the screwdriver method with it running (scary!!) against the cover below the alternator i didnt hear grinding from that cover, but im just curious, has anyone ever herd of the timing chain snapping with a 4.0L or are they known to be reliable to see 400 or 500 k on a engine ??

whats the chances of my timing chain breaking on my 4.0L , are they known to snap, like is it common on a high mileage 4.0? ? ?

and if it ever broke which it will have to before i replace it, is the 4.0L a interference or non-interference engine ?? will it smash the valves or can i just install a new chain and head back to the streets

thanx guys

greasefingers · 07-28-2007, 08:35 PM

I have never heard of a Jeep timing chain breaking.

jeepunlimited · 07-28-2007, 08:36 PM

thanx man!!! kidna puts me at ease....i know the 4.0L is supposed to be a noisy motor , this was just a new noise i wanted to clairfy !!

any other opinions ?

greasefingers · 07-28-2007, 08:43 PM

My engine is very noisy. The exhaust manifold has a slight leak and the valves clank about which it has always done that since it was new. Then again it is 13 years old and expected.

jeepunlimited · 07-28-2007, 08:49 PM

i think it could maybe have been the exhuast leak it has!!!...never thought of that , it was a grinding or stratching sound.... it is expected with 370 000 and i dont mind it , i just wanna make sure the timing chain isnt a common thing that will end up getting me stranded down the road,, my valves are very noisy too ....o well

jeepunlimited · 07-28-2007, 10:06 PM

anybdoy else by chance herd anything bad about 4.0L timing chains ?

ben_wagner · 07-28-2007, 10:34 PM

For what it's worth, I've never heard of one breaking.

YJinMN · 07-28-2007, 11:22 PM

Never. And I believe that the 4.0 is a non- interference engine..

MP

**UltimatE** · 07-29-2007, 10:59 AM

Never heard of one breaking either.

colinzj · 07-29-2007, 11:32 AM

They're known to stretch a little at high mileage, but that's about it. It's considered a lifetime part.

The engine's a non-interference design anyway like YJinMN mentioned, so even if you do manage to break one... you're just not going anywhere until you replace it.

gomes512 · 07-29-2007, 08:11 PM

Hehe yeah mines loud to, even with a 40 weight diesel oil that thing runs just as loud as the biplanes at the air show. Puts a big

on my face, I like that motor. Just like mentioned above I've never heard of a 4.0L busting a timing chain.

Then again I never really hear about any mechanical problems with that motor if oil is changed regularly. Just sensors and electric problems, it's definitely up there in the reliability department with the good 'ol slant 6.