Diagnosing noise from 2.5 (could it be the timing chain?)

Fughuert

Fughuert

TJ Enthusiast
Joined
Nov 26, 2018
Messages
375
Location
New England
I noticed this noise start up at first it was a light metallic rattle only heard at idle but now it sounds like someone shaking a jar of rocks, still only really heard at idle and shows no other issues.

Seems to increase with engine rpm but I can't hear it running down the road, only while revving in my driveway.

Runs fine down the highway but I did have a hiccup starting it up today where it fired and died then fired and ran no problem.

Here is the video the phone is pretty much over the fan shroud during the video.
 
If you want to check the chain put a breaker bar or big wrench on the crank and turn it back and forth (obviously with the engine off). You will easily feel the crank turn and the slack in the chain before it starts turning the camshaft if it is bad. You can also often hear the chain rattle as the slack is taken in when you do this. If you have a wrench that'll fit it is a really quick and easy test.
 
  • Like
Reactions: Blondie70
This was the sound of the timing chain tensioner failing.

Turns out you can drive for about 4 days once it sounds like this then have your chain snap 2 miles from home leaving only a few hours at night to get it fixed.
 
  • Like
Reactions: Blondie70
Wasn’t too bad, plenty of room in the 4 cylinder bay was about a 2.5 hour driveway job not knowing what I was doing.
 
Fughuert said:
I noticed this noise start up at first it was a light metallic rattle only heard at idle but now it sounds like someone shaking a jar of rocks, still only really heard at idle and shows no other issues.

Seems to increase with engine rpm but I can't hear it running down the road, only while revving in my driveway.

Runs fine down the highway but I did have a hiccup starting it up today where it fired and died then fired and ran no problem.

Here is the video the phone is pretty much over the fan shroud during the video.
Click to expand...
did you just replace the tensioner or did you need to buy a new chain and gears? got the same problem in mine, randomly started doing it this morning
 
Fughuert said:
I noticed this noise start up at first it was a light metallic rattle only heard at idle but now it sounds like someone shaking a jar of rocks, still only really heard at idle and shows no other issues.

Seems to increase with engine rpm but I can't hear it running down the road, only while revving in my driveway.

Runs fine down the highway but I did have a hiccup starting it up today where it fired and died then fired and ran no problem.

Here is the video the phone is pretty much over the fan shroud during the video.
Click to expand...
did you replace just the tensioner or did you get all new chain and gears? i got the same exact sound that popped up this morning
 
bcdawson27 said:
did you replace just the tensioner or did you get all new chain and gears? i got the same exact sound that popped up this morning
Click to expand...
I did chain and gears since the chain broke while I was driving, if you catch it before it breaks you could probably do just the tensioner but why not all of it while you’re in there. You’re supposed to do it at 150k.

Careful with the oil pan gasket it shares with the timing chain cover. And don’t forgot the little tensioner tabs that slot into the cover I almost did. It’s different from the 4.0.
 
  • Like
Reactions: Fishtaco
Fughuert said:
I did chain and gears since the chain broke while I was driving, if you catch it before it breaks you could probably do just the tensioner but why not all of it while you’re in there. You’re supposed to do it at 150k.

Careful with the oil pan gasket it shares with the timing chain cover. And don’t forgot the little tensioner tabs that slot into the cover I almost did. It’s different from the 4.0.
Click to expand...
did you have any problems with it running while the chain was ticking? i would think if the timing chain was loose the engine wouldn’t run the same
 
Top Bottom
Back