Hydraulic drive belt tensioner?

Tiny
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.
Wednesday, October 4th, 2023 AT 5:48 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 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.
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Thursday, October 5th, 2023 AT 9:38 AM
Tiny
JEFF HERMAN
  • MEMBER
  • 486 POSTS
I heard they are rebuildable, but I'll just wait for the new part to come.
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Thursday, October 5th, 2023 AT 12:49 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Can you upload an image of the part when you are rebuilding it? I have not seen that before, we just replaced them.
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Friday, October 6th, 2023 AT 9:32 AM

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