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View Full Version : Engine Knock Vs. Timing Belt Tensioner


SilverBullet75
03/28/2008, 05:23 PM
http://www.vehicross.info/forums/showthread.php?t=10722&page=3

A HUGE THANK YOU TO COWBOYERIK!!!!!!!!!!

I've been in a VX depression ever since I heard that darned knocking sound in the motor. I even warned my wife about the "potential" of the motor going kaput long ago. After reading CowboyErik's post, I felt I had hope still. Sure enough! I pulled off the passenger side timing belt cover enough to push on the belt. Without any trouble at all I was able to deflect it by almost an INCH! So, after about 45 minutes I had the front end torn apart and found that the timing belt tensioner went bad!!! I can plunge the piston with my hands with ease, and there is oil leakage around the "pushrod" base. (see pics).
SO, IF YOU THINK YOU HAVE ROD KNOCK/ENGINE FAILURE, CHECK THIS BEFORE SENTENCING YOUR VX MOTOR TO DEATH!!!!
http://www.vehicross.info/gallery/data/500/tensioner1.jpg
http://www.vehicross.info/gallery/data/500/tensioner2.jpg
Ldub
03/30/2008, 10:25 AM
This is good info., I've heard of this on the 3.2(mostly sohc?, not sure), but this is the first I've seen of it on the 3.5.:_wrench:
Thanks to Cowboy Eric & Silver Bullet 75.:thumbup:
Ebenezr
12/14/2010, 11:25 AM
WOW! So this could be my number 1 cylinder Knock! I have been bracing myself for several months now for the engine to DIE.
SilverBullet75
12/14/2010, 02:44 PM
If you take the timing belt covers off, you should be able to deflect the timing belt pretty easily by hand. If this is the issue, you just saved $k's!
cwmoser
12/31/2010, 01:46 PM
WOW! So this could be my number 1 cylinder Knock! I have been bracing myself for several months now for the engine to DIE.

Ebenezr ... I have a knock that appears to be on number 1 cylinder too.
Did you check your Tensioner? If so, what did you find?

Thanks

Carl
BigSwede
12/31/2010, 08:09 PM
On the 3.2Ls, a diagnostic for the timing belt tensioner is if the knock goes away at higher rpm, above 2000-2500 rpm. But it can definitely sound like a death rattle, when my tensioner went out at Moab, everybody who heard the motor looked like they were at a funeral. But instead it was a $65 part.
Ebenezr
01/01/2011, 05:19 AM
I can't get to it. Prying the cover back I can't do. When I put a stethascope on it the tap is loudest coming from the timing cover top bolt which enters right into the no. 1 area in the head. It will have to be torn apart to check but for the engine runs great. I am going to rev the engine today like BigSwede said and see if it disappears.
cwmoser
01/01/2011, 06:11 AM
I can't get to it. Prying the cover back I can't do. When I put a stethascope on it the tap is loudest coming from the timing cover top bolt which enters right into the no. 1 area in the head. It will have to be torn apart to check but for the engine runs great. I am going to rev the engine today like BigSwede said and see if it disappears.

My engine tapping goes away above 2500 rpms too and the engine runs great.
I need to open the timing covers and take a look see too.

Carl