Drive Belt tensioner leaking at 40,700 miles per dealer

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2015 Mazda CX-5 Touring FWD - Crystal White
The tensioner on my 2015 CX5 Touring went out at 55k. Leaked/chirping with AC and low RPMs. Mazda dealer diagnosed it for me. The comments here made me believe I could replace it myself.

I got it done in about an hour and a half. Jacked up the car, removed the bottom splash panel (10mm). Removed the tension by putting the 17mm wrench on the solid sliver/aluminum protrusion and turned counter clockwise to depress the hydraulic piston of the tensioner. Belt slipped right off pretty easy. This may take two people. I slipped the belt off while the father-in-law held the tensioner back. We did all this with regular sized wrenches.. but the extended wrenches would surely make this easier. Removed the top and bottom bolts with a 12mm wrench. Bottom one was tricky, actually needed to put a pipe on the end the wrench to get sufficient leverage. A ratcheting wrench made the removal easier. Although on the bottom bolt, stop using the ratchet cause you will get the ratchet stuck between the half-removed bolt and the car frame.

Overall, you CAN do this without the extended length wrenches. You PROBABLY want a 2nd set of hands to help. One person under the car, one above. Save yourself the 430$ the dealer quoted. Found the OEM tensioner on ebay for 75 and a new serpentine belt for 22.
 
V
13' CX-5 and 16' Mazda6 both Touring w/Tech/Bose
The tensioner on my 2015 CX5 Touring went out at 55k. Leaked/chirping with AC and low RPMs. Mazda dealer diagnosed it for me. The comments here made me believe I could replace it myself.

I got it done in about an hour and a half. Jacked up the car, removed the bottom splash panel (10mm). Removed the tension by putting the 17mm wrench on the solid sliver/aluminum protrusion and turned counter clockwise to depress the hydraulic piston of the tensioner. Belt slipped right off pretty easy. This may take two people. I slipped the belt off while the father-in-law held the tensioner back. We did all this with regular sized wrenches.. but the extended wrenches would surely make this easier. Removed the top and bottom bolts with a 12mm wrench. Bottom one was tricky, actually needed to put a pipe on the end the wrench to get sufficient leverage. A ratcheting wrench made the removal easier. Although on the bottom bolt, stop using the ratchet cause you will get the ratchet stuck between the half-removed bolt and the car frame.

Overall, you CAN do this without the extended length wrenches. You PROBABLY want a 2nd set of hands to help. One person under the car, one above. Save yourself the 430$ the dealer quoted. Found the OEM tensioner on ebay for 75 and a new serpentine belt for 22.
Good job.

I was gifted extended ratcheting wrenches......perfect for this DIY project. Slim enough to fit. Hey what type of pipe you recommend for more leverage?
 
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2015 Mazda CX-5 Touring FWD - Crystal White
Good job.

I was gifted extended ratcheting wrenches......perfect for this DIY project. Slim enough to fit. Hey what type of pipe you recommend for more leverage?
It was a random pipe I had laying on the work bench. If I had to guess it was like 1/2dia by 12 inches. Anything that you can use to get leverage on the other end of the wrench would work.
 
I had my tensioner replaced on my 16 2.5 at 2 years, about 200k, it literally blew apart, was covered under warranty. Love the unlimited mileage warranty!
 

yugrus

Contributor
V
CX-5 GT
How does the tensioner leak if it is not hydraulic?
It's a physical spring tensioner that has nothing to do with engine lubrication system.
The "leak" is from the spring lubricant seeping out of the gasket...
 
Have there been any reports of this premature tensioner failure occuring on redesigned models 2017-2019? Or 2019 specifically?
 

Kedis82ZE8

Contributor
V
'15 CX-5 GT AWD
I noticed a lot of residue on mine yesterday. At least it isn't an expensive part too difficult to replace. I need to keep an eye on it. Either it is now failing at 53K miles or is just long term buildup from the timing chain cover oil weep/leak. I've never had an auto-tensioner fail on me.
 
V
CX5 GT-R
I noticed a lot of residue on mine yesterday. At least it isn't an expensive part too difficult to replace. I need to keep an eye on it. Either it is now failing at 53K miles or is just long term buildup from the timing chain cover oil weep/leak. I've never had an auto-tensioner fail on me.
No kidding. I can deal with 0.0001% more NVH for the sake of a simple spring-loaded model that won't break.
 
V
13' CX-5 and 16' Mazda6 both Touring w/Tech/Bose
I noticed a lot of residue on mine yesterday. At least it isn't an expensive part too difficult to replace. I need to keep an eye on it. Either it is now failing at 53K miles or is just long term buildup from the timing chain cover oil weep/leak. I've never had an auto-tensioner fail on me.
Post a picture. CX-5 at 108k miles still on original tensioner. Got mine replaced for Mazda6 by dealer under warranty (I complained to Mazda USA). In the case of my Mazda6, that tensioner may have contributed to leaking of my water pump. (again covered under warranty).

I've purchased a Tensioner as a backup as its the same part number throughout all Mazda skyactiv engines. Can be done as a DIY project. Clean off the rubber boot and I suggest you inspect it with a flashlight every oil change like I do.
 

ColoradoDriver

Gen-1 Kodo Design
Contributor
L
Denver, CO
V
2014 CX-5 Touring
I noticed a lot of residue on mine yesterday. At least it isn't an expensive part too difficult to replace. I need to keep an eye on it. Either it is now failing at 53K miles or is just long term buildup from the timing chain cover oil weep/leak. I've never had an auto-tensioner fail on me.
When mine failed, upon visual inspection it was completely covered in blackish oil/fluid.
 
V
2014 Mazda 6 GT with MRCC
No kidding. I can deal with 0.0001% more NVH for the sake of a simple spring-loaded model that won't break.
Mine failed at 60k on my 2014. The replacement seems fine at 100k. The reason they use the hydraulic tensioner is not noise, but efficiency. It only tightens the belt under load/rpm. When idle and low oil pressure occurs it will slacken and lessen the wear on the belts and pulleys. Under low rpm it also runs a looser belt. It's no big deal to me as all tension methods have problems.
 
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2014 mazda cx-5 touring FWD
It's not hydraulic as we think of fluid pressure doing work.It's just a spring applying tension to the belt but has viscous damping (using a thick oil) just like a shock absorber ,to prevent belt whipping/flapping whereas a spring alone may allow oscillation.And it doesn't use engine(or any) oil pressure.
 

Chris_Top_Her

Banned
Moderator
Contributor
L
San Antonio, Texas
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'15 CX-5 Miata AWD
Yea my 2nd tensioner has been on the fritz for a minute now.. I should probably replace it soon, as I'm certain it's the reason the clutch on my ac compressor got jacked up (since replaced).
 
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13' CX-5 and 16' Mazda6 both Touring w/Tech/Bose
I keep a spare tensioner in my garage and inspect the ones in both cars every oil change. So far so good.
 

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