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Idle pulley braket design failure. Serious

26K views 77 replies 31 participants last post by  sid6581  
#1 ·
All:

I just posted a complaint at the NHSTA. I was hearing a noise around the engine area and it was the idle pulley. After reading some threads here. it seems to be a common problem. I decided to change the parts myself.

After taking the pulley and bracket apart I noticed a serious design flaw in the bracket. It cannot support the bending moments applied by the idle pulley shaft.

The noises I heard were from the pulley rotating off axis and rubbing (cutting) the metal from the bracket, the adjusting nut and some of the main crank shaft pulley.

I will post some images tomorrow. I forgot my camera at work. I would also try to take some pictures of the fatigue marks in the cracks using a microscope (might be hard to take the pictures).

Here is my complain to the NHSTA:

Heard noise from engine compartment. Upon investigation noticed idle pulley was vibrating and make the sound. I investigated online at www.nissanmurano.org for similar problems. I found a series of reports that the braket that holds the idle pulley was broken.

I disassemble the pulley and found the bracket broken. Upon examination of how the bracket broke seem that the bracket is under-designed. The crack seems to indicate that the bracket broke by bending fatigue. I saved all the bracket pieces and I going to evaluate under a microscope.

The failure to this idle pulley could lead to an alternator not providing energy to the car and a more serious consequences.

Sorry for my bad English and poor grammar, i'm just typing too fast and not reading back for mistakes.
 
#3 ·
Gialdy-

There are quite a few VQ-series engines out on the road. I wonder if this bracket is unique to the MO or is it on other vehicles as well.

-njjoe
 
#5 ·
More pictures

The pulley was riding in this adjustment screw and actually cut it. I have more pictures if anyone else is interested.

I plan to change this bracket every 20K miles until Nissan upgrades this part. It's only $16 and it is really hard to see if it broken unless you take it apart. Changing the braket is not all that hard, if you have the right tools(universal joint).
 

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#6 ·
Gialdy-

In the photo below, is the circled feature a break or a cut? Was it cut by the pulley? Is it broken/cut clear through?

Thanx.

-njjoe
 

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#7 ·
Cut

njjoe said:
Gialdy-

In the photo below, is the circled feature a break or a cut? Was it cut by the pulley? Is it broken/cut clear through?

Thanx.

-njjoe
Njjoe:

Since the bracket broke, the pulley was rotating off axis and it started to cut that screw. I change the part before it finished cutting that screw or damaging the pulley or braking the belt.
 
#8 ·
Great pictures! This is definitely something I will keep an eye on. As has been the case, many common Murano problems have been identified first on this forum, then months or years later, Nissan issues a recall or TSB.
 
#11 ·
We are starting to gather several stories along this line.
Seems to me, that a busted bracket has been happening forever, but certainly not in large numbers.
As we accumulate more Muranos there seem to be more bad brackets........or is it a mileage thing?
I have 30K and no strange sounds.

I assume that the only way to see this is from the bottom...........and I doubt that it is all that easy then......

Might have to join Gialdy and report every one of these to NHSTA.
He is right.
If the bad Alternator was worth a recall, so is the bad alternator bracket (If there is enough of them.....)
 
#12 ·
I have a 2003 Murano SL 47K Mi, and recently noticed a puddle of coolant on the floor of my garage. Turns out that the Idler Pulley Bracket (also called Belt Tensioner Bracket) had completely failed (see attached photo). When the bracket failed, it pierced one of the coolant hoses.

I was surprised to learn that the Idler Pulley Bracket is not considered part of the engine & drive train, and is excluded from the Engine & Drive Train Warranty.

I'm in the process of escalating through Nissan, since this part failure seems to be experienced by other owners as well.

Any suggestions are appreciated!

Thanks....
 

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#13 ·
Muranolover:

Your picture confirms my assumtion. Look at the line of fracture. It is identical to mine. This is a desing flaw of the pulley. The bracket needs to be thicker or a stronger material. As the engine accelerate, it adds more tension to the pulley (more than the normal tension when the engine is off). This tension is translated thru the shaft and bolt to the bracket. The braket is seeing a bending moment . The line of fracture seems to be exactly were the stress concentration should be at.

I used to have access to a high power microscope (at Eng lab). It would be very nice to look at the fracture for see the propagation of the crack. It will give define evidence that this is a design flaw.

It would also be interesting to perform some FEA (Finite Element Analysis) on a computer model. Something that the Nissan's engineers should be doing.

If anyone experience this same scenario, I'll suggust theat you save the bracket. It might come handy if/when they do a recall to get some cash back.

Also, when I had thi failure, it started by a wierd noise. The car was running fine for more than 2 months. I found the problem. when I finally took to time to investigate the source of the noise. The most problable indicator of a problem is a lost in MPG or a loss in power. The easiest way to see the bracket is from the passenger side wheel. I think it is easier to feel the broken bracket than to see it. It's being a while since I change this stuff.
 
#14 ·
I had this exact problem with my '04 Murano at about 12,000 miles. I diagnosed the problem as a bad idler pulley and the servuice tech agreed. We waited a weeks for the part, then he discovered the pulley was OK, the bracket was the culprit, so another wait of a couple of days.
No problems since.

For those that listen, the engine noise resembled a bad water pump bushing/bearing. Fairly obvious at idle, tended to disappear at speed.
 
#15 ·
Just looking at the part...

Makes me shudder at the lack of quality: In design, manufacture and obivious lack of care.

It really bugs me to see such a piece of junk on the car.
 
#16 ·
what is more dumbfounding is the fact that it is easily replaced by a spring loaded tensioner design.
who oh why does Nissan have to stick to 50's belt tensioning design is beyond me. Like I said, chevy has had this design for decades and my wife's hyundai has it as well.

The only reason to have it is to make folks go to Nissan to change belts.

:rolleyes:
 
#17 ·
Bye Bye Idler Pulley at 35,000 Miles!

Hi All,
I just joined, just first want to say that over the last year or so you have all given me great tips every time something was wrong with my 2004 Murano. Your expertise and tips are SOOOO much appreciated. Especially by me, ain't easy being a woman with a car that has so many problems! I always think they are scamming me so I come here to find out.

That being said, I just took my car in after an all of the sudden clanging noise - at 35,000 miles. New Idler Pulley AND Bracket. I just got back from the 30K service TWO days before. So here I'm thinking my car is like new and the clanging starts. $99 for labor, $69.50 for the pulley, and $25 for the bracket. Authorized Nissan Dealership. I'm gonna kill somebody.

NOW, a day after getting my car back, I have a kind of humming noise that sounds like a groan when the car is in 15 mph and accelerates... also, on the highway it gets quite loud even when i'm going 50 and accelerate. sounds like it's coming from the same area.

going back tomorrow morning to see what this is.

I agree that this broken pulley is ridiculous, especially at 35,000 miles. If there is something I can do for you to join the effort to get Nissan to address this issue please tell me.

any ideas on the humming or whether women get taken for rides at the dealership!???

Thanks in advance!
 
#18 ·
Re: Bye Bye Idler Pulley at 35,000 Miles!

herewego said:
Hi All,
I just joined, just first want to say that over the last year or so you have all given me great tips every time something was wrong with my 2004 Murano. Your expertise and tips are SOOOO much appreciated. Especially by me, ain't easy being a woman with a car that has so many problems! I always think they are scamming me so I come here to find out.

That being said, I just took my car in after an all of the sudden clanging noise - at 35,000 miles. New Idler Pulley AND Bracket. I just got back from the 30K service TWO days before. So here I'm thinking my car is like new and the clanging starts. $99 for labor, $69.50 for the pulley, and $25 for the bracket. Authorized Nissan Dealership. I'm gonna kill somebody.

NOW, a day after getting my car back, I have a kind of humming noise that sounds like a groan when the car is in 15 mph and accelerates... also, on the highway it gets quite loud even when i'm going 50 and accelerate. sounds like it's coming from the same area.

going back tomorrow morning to see what this is.

I agree that this broken pulley is ridiculous, especially at 35,000 miles. If there is something I can do for you to join the effort to get Nissan to address this issue please tell me.

any ideas on the humming or whether women get taken for rides at the dealership!???

Thanks in advance!
Welcome Ms herewego!

I think the noise you're hearing is a mis-aligned idler pulley or the belt they put on is too loose?

Please let us know what happened.;)


Dan
 
#19 ·
Re: Bye Bye Idler Pulley at 35,000 Miles!

herewego said:
That being said, I just took my car in after an all of the sudden clanging noise - at 35,000 miles. New Idler Pulley AND Bracket. I just got back from the 30K service TWO days before. So here I'm thinking my car is like new and the clanging starts. $99 for labor, $69.50 for the pulley, and $25 for the bracket. Authorized Nissan Dealership. I'm gonna kill somebody.
Herewego-

30,000 mile service followed two days later with a failed idler pulley bracket? Coincidence? Maybe not.

There is a very good possibility that the mechanic may have improperly tightened the idler pulley during the 30,000 mile service, which then caused the idler pulley to fail two days later. I would definitely bring that up during your next visit.

-njjoe
 
#20 ·
Dan and NjJoe,

Thank you! Well I checked this morning before heading out and was so pleased to hear your ideas. I'm back with a fixed car and didn't pay anything.

The noise was a bolt on the gasket near the muffler or something totally unrelated to the idler pulley thank god. so they fixed it for free and the noise is gone.

As for the idler pulley, I asked the mech when I got in about whether it was possible that the mechanic may have improperly tightened the idler pulley during the 30,000 mile service, and he said that they don't even touch the idler pulley during the 30,000 mile service. "we don't go anywhere near it" is what he said.

I'm happy the problems are fixed, but I'm not going to this dealership again. I've had numerous problems (did i mention i've had my bose 5 disc radio replaced twice!!??) and each time this place handled it like a bunch of jerks. I won't go into detail (like the time i got my car back after an oil change and it stalled on the way home, the guy forgot to put something back on, they told me)

I think it definately helped to walk in there with some terminology, knowledge is power, right?

So thank you so much Dan and NjJoe, you guys are the best. Really truly appreciate it.

~Suzanne
 
#21 ·
OK, we're getting enough stories about this happening that I feel I need to check mine out. No strange noises or anything, just want to watch for fatigue.

Can anyone explain to me exactly how to see this without taking my MO apart? Where exactly is it located? What should I be looking for in terms of wear?
 
#22 ·
herewego said:
As for the idler pulley, I asked the mech when I got in about whether it was possible that the mechanic may have improperly tightened the idler pulley during the 30,000 mile service, and he said that they don't even touch the idler pulley during the 30,000 mile service. "we don't go anywhere near it" is what he said.
That's funny. If you called them and asked what services they perform on the 30,000 mile service I bet all the money in my pockets they would say they inspect and tighten all of the belts.

-njjoe
 
#23 ·
Suzanne: It was my pleasure though I wasn't much help. Sometimes it's just good to know someone else is 'listening';).

Hope you continue enjoying your Mo for "many moons" .:cool:


Dan
 
#24 ·
Hi herewego,

Sorry that you had a similar problem with the premature failure of the idler pulley & bracket that a lot of us have had.

It would be helpful in order to get an investigation going (and potentially a recall by Nissan) if folks post complaints to the NHSTA website, Office of Defect Investigation. It should take about 10 minutes.

http://www-odi.nhtsa.dot.gov/ivoq/

Thanks much!!
 
#25 ·
Just purchased an 04 MO about 30 days ago, only to experience the noise mentioned by Gialdy.

Took it into the dealer and it was diagnosed as a broken Idler Pulley Bracket. Both Bracket and Pulley were replaced under warranty. The service advisor also informed me that my 'belts' were cracked and worn and that they should be replaced. I did so. Now though, when I perform a cold start, I hear a sharp squeal from the engine compartment, like the sound of the belt slipping.

Can anyone comment on this issue? I do plan to take it into the dealer to have it checked out.

Thanks!