Hydraulic drive belt tensioner?

JEFF HERMAN

MEMBER
2012 JEEP LIBERTY RENEGADE
3.6L
V6
4WD
AUTOMATIC
150,000 MILES

I opened the rubber dust cap, and the oil came out. There's still a lot of tension with just the spring. I've read about people just adding some ATF. If I put oil, maybe hydraulic jack oil in it, how much would I put in and should it be compressed a few times to allow the oil into the piston? I have ordered a replacement tensioner, but I don't think this one failed. It's just very hard to compress.

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,536 POSTS

Hi Jeff,

It looks like the tensioner is bad I don't think you can refill it, and if so, it would just leak out once again, here is information the drive belt tensioner and how to replace it in the images below.

The automatic belt tensioner (1) is a hydraulically loaded arm and pulley assembly. The tensioner assembly is designed to apply constant pressure on the accessory drive belt to maintain proper belt tension.

The hydraulic strut (2) utilizes an internal spring and a one way valve that controls the oil pressure to the connecting rod. The valve allows the oil to build pressure in the piston to reduce the motion to the strut caused by the engine's crank pulsations and allows for the proper tension to the accessory drive belt and pulleys.

Check out the images (below). Please let us know if you need anything else to get the problem fixed.

Images (Click to make bigger)