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Unread 04-25-2014, 04:41 PM   #1
SLADE
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Serpentine Belt tensioner leaking oil.

Started to take the drain plug out last night to change the oil (2013 3.6 Pentastar) and noticed oil had leaked down the passenger side of the block starting mid way up the front working it's way toward the bottom and running clear to the bell housing. It's a noticeable amount that shouldn't be there, so I started looking for the source. Appears to be coming from the lower part of the belt tensioner that has a single bolt to the block.


Has anyone else had their belt tensioner leaking?

Is it a common leak for the 3.6?

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Unread 04-25-2014, 04:48 PM   #2
RockyClymer
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Unless that bolt hole intersects an internal oil passage, can't visualize it. The tensioner on my 3.8 is a lifetime bearing (I did not specify how long lifetime means...until it wears out).
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Unread 04-25-2014, 05:11 PM   #3
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i been thinking about that part for a spar. One of our club members had that go out and had to trailer it out(TJ). Getting ready for the Dusy trip and i would hate to have that go down 8o miles from nowhere. wonder what they charge for it. Bet its arm and leg.
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Unread 04-25-2014, 05:18 PM   #4
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This is at the bottom of the tensioner. The oil is higher on the block toward the top of the tensioner, but while looking at everything with the engine running I could see little bobbles coming from the bottom part of the tensioner (right to the left of the crank pulley/ bottom of the picture almost out of sight).




You can see the seam right where the smooth finish is. Not sure if the top part of the lower bracket is leaking also and the oil is being blown higher up on the motor or not.

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Unread 04-25-2014, 05:28 PM   #5
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I would clean off all the oil residue and keep an eye on it to see if the source can be determined.


This description of the tensioner is from the 2012 factory service manual:

The automatic belt tensioner 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 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.
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Unread 04-25-2014, 06:06 PM   #6
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Thanks for the description of the tensioner.


Quote:
Originally Posted by ronjenx View Post
I would clean off all the oil residue and keep an eye on it to see if the source can be determined.

I'd like to, but being under warranty I'm going to leave it alone and let them figure it out. Going to drop it off tomorrow so it can get fixed.
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Unread 04-25-2014, 06:40 PM   #7
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Quote:
Originally Posted by SLADE View Post
Thanks for the description of the tensioner.





I'd like to, but being under warranty I'm going to leave it alone and let them figure it out. Going to drop it off tomorrow so it can get fixed.
i would guess that it wont be in stock. being that its "lifetime". can you find out what the cost of this hydraulically pressurized wonder of modern engineering cost? once the do the work. post it here? looking at this it would bet we are in the 2-400$ range. seems to be a target price on about anything on these if not much more.

my shifter module was like 400 but warrantied. First time i might be glad i did get that extended warranty.
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Unread 04-25-2014, 07:01 PM   #8
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Quote:
Originally Posted by 222Doc View Post
i would guess that it wont be in stock. being that its "lifetime". can you find out what the cost of this hydraulically pressurized wonder of modern engineering cost? once the do the work. post it here? looking at this it would bet we are in the 2-400$ range. seems to be a target price on about anything on these if not much more.

my shifter module was like 400 but warrantied. First time i might be glad i did get that extended warranty.
I have seen them online for $113 to $184.
Amazon was $113; Quadratech was $184.
The various online MOPAR Parts dealers were anywhere in between.
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Unread 04-25-2014, 07:04 PM   #9
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I'm not planning on it being done or fixed tomorrow. Just going to get it there so they can get to it first of next week. I'm figuring on driving my truck next week and giving them time to fix it. I'll get what ever prices I can on it and let you know.
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Unread 04-27-2014, 02:23 PM   #10
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Let me get this right, the tensioner is controlled by engine oil pressure? Or is it using it's own oil and spring? Couldn't they just use what s been working fine for 30 years on serp's, a spring loaded tensioner?
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Unread 04-27-2014, 02:49 PM   #11
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Quote:
Originally Posted by 73azbronco View Post
Let me get this right, the tensioner is controlled by engine oil pressure? Or is it using it's own oil and spring?
The description isn't clear on that.

Inspection upon removal can provide the answer.
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