serpentine belt woes

Tree Catcher · **Posted:** Sun Sep 25, 2016 7:35 pm

While driving home last week, my jeep suddenly lost power. I get it towed home and start the inspection. Hmm no serpentine belt, where did it go, I look around the crank only to find it wrapped up there. Since I have just changed over both the timing belt and the serpentine belt two years and 30 thousand miles ago, I knew what I had to do to in order for closer inspection. I take the radiator and everything else off to get to the crank, I pull the belt expecting to just take off the remnants of the old belt. Instead I find that the belt went behind the cover and is now lodged into the timing belt and I now get to replace the timing belt and I'm wondering If I lost time and possibly broke the rockers. How hard is it to retime the engine and also replace the rockers. I have taken apart motorcycle engines in the past, so I'm somewhat mechanically able to do the job.. Sadly the wife asked if we should repair it, I just smiled and said yep, it's better to fix it than have a car payment. Yup I'm a sucker for this little beast.

Sean

jws84_02 · **Posted:** Sun Sep 25, 2016 8:30 pm

How the heck does that happen? Did a serpentine component break? Anywho, if it did skip or loose timing it isn't that difficult to get it back in time

WWDiesel · **Posted:** Sun Sep 25, 2016 8:41 pm

Yes please, tell us what caused the serpentine belt to let go, it had to be either the tensioner pulley, or one of the other major pulleys to cause that kind of catastrophic failure... :shock:

At your point, I would pull the timing belt cover, after you get the wrapped up serpentine belt removed, an inspect the timing belt for damage, and then to be on the safe side, recheck the engine timing (cams) by inserting all the timing pins and flywheel pin.... If you find it out of time, I would pull the rocker cover and inspect all the rockers for damage.... :roll:

Tree Catcher · **Posted:** Sun Sep 25, 2016 10:19 pm

The only thing that I suspect might be the power steering, it had been making noise over the past few weeks. I was going to have the fluid flushed out next week. The tensioner was newish. I'm still trying to figure our how parts of the serpentine belt went into the timing belt and lodged itself in there.

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

Tree Catcher wrote:

I'm still trying to figure our how parts of the serpentine belt went into the timing belt and lodged itself in there.

This is relatively rare but there are at least two other cases that I'm aware of where the serpentine belt shredded and wreaked havoc under the timing cover

Rixram · **Posted:** Mon Sep 26, 2016 8:26 am

I had an issue a few years back where the alternator coupler pulley was on th3e fritz, and causing catch-no catch shock to the serp belt items. Over time, it apparently caused the serp belt tensioner to begin to fail, and it was slightly slanted from the damage. It ate a belt while driving.

A replacement alt (de)coupler pulley and a replaced serp belt tensioner are likely in order.

Personally, I find it beneficial to include replacement of these items at the 100K mile servicing.

WWDiesel · **Posted:** Mon Sep 26, 2016 10:20 am

It is not a bad idea to remove the serpentine belt every so often and check the idler pulleys and the pulley on the tensioner along with testing the override pulley on the alternator and make sure everything is still functioning correctly.. :wink:

My experience:
I had to replace my alternator last week; While I had the alternator off, I tested all the pulleys one at a time and found the top idler pulley bearing was extremely stiff (would not spin easily by hand) like it was getting close to failure. Replaced it with one I had in stock while I had the belt off.

While returning from a short road trip to a machine shop in a nearby city, the alternator charge light alarm came on and dinged. A little bit later, the battery light alarm came on and I turned off all nonessential equipment i.e. AC, blower fan, radio, Sirius, etc... hoping to just make it home on the battery. I did make it thank goodness; battery got down to <10 volts and motor was running a little funny and sounded a little odd at idle. After turning engine off, I tried to restart, it would not even click! Whew!!! :-)r

Replaced the alternator with a Autozone unit that came with a new override pulley and has a lifetime warranty! It looked exactly like the alternator I removed, and they had the best price of anyone around!
Also, they were kind enough to let me remove and keep my old override pulley since I had just replaced it last year with a high dollar Litens pulley!!!

kissfan79 · **Posted:** Mon Sep 26, 2016 11:28 am

Wow....that's crazy. Glad you made it home safe and sound.

GraemeT · **Posted:** Tue Sep 27, 2016 1:46 am

Ceearedeedriver wrote:

Tree Catcher wrote:

I'm still trying to figure our how parts of the serpentine belt went into the timing belt and lodged itself in there.

This is relatively rare but there are at least two other cases that I'm aware of where the serpentine belt shredded and wreaked havoc under the timing cover

I experienced this with a Renault diesel - the serpentine belt was neglected and had started to fray making a noise. I checked it and decided to drive the mile left on the journey. 10 yards short the car stalled - belt under the plastic timing cover, wrapped around the timing belt and killed the top end (interference engine).
My local garage commented that they had just seen an identical failure on another car when I mentioned it.
Moral of the story is check/replace that belt.

On your one - check the timing - good luck

Graeme

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

GraemeT wrote:

I experienced this with a Renault diesel - the serpentine belt was neglected and had started to fray making a noise. I checked it and decided to drive the mile left on the journey. 10 yards short the car stalled - belt under the plastic timing cover, wrapped around the timing belt and killed the top end (interference engine).
My local garage commented that they had just seen an identical failure on another car when I mentioned it.
Moral of the story is check/replace that belt.

On your one - check the timing - good luck

Graeme

Not just the belt also watch the tensioner, idlers and other components driven by that belt. Routine PM is key. Listen for unusual noises, check for play and address issues promptly as they arise.

People assume that a sepentine failure is fairly benign since it doesn't drive any critical components. It's instilled into us around here that the timing belt needs to be changed every 100K but failure on the other side of that cover can be just as devastating.

WWDiesel · **Posted:** Tue Sep 27, 2016 9:50 am

Ceearedeedriver wrote:

Not just the belt also watch the tensioner, idlers and other components driven by that belt. Routine PM is key. Listen for unusual noises, check for play and address issues promptly as they arise.
People assume that a sepentine failure is fairly benign since it doesn't drive any critical components. It's instilled into us around here that the timing belt needs to be changed every 100K but failure on the other side of that cover can be just as devastating.

X2
Good advice: Need to remove and check those idler and tensioner pulleys every so often, maybe at least once a year or sooner if you hear a noise or suspect a problem. It only takes a few minutes to de-tension the belt and then spin each pulley by hand to make sure it spins freely and then feel for any roughness in the bearing. This little test may save you lots of money if belt were to break or come loose because of a bad pulley and end up wrapped up in the timing belt like Tree Catcher's did... :roll:

It's a good idea to also test the alternator override pulley at the same time while the belt is de-tensioned...

papaindigo · **Posted:** Tue Sep 27, 2016 11:17 am

My

serpentine belt should be changed every 50K miles at which time of course check idler pulleys. In between check serp belt idler for "bounce" which is a good indicator of pulley problems including alternator decoupler; takes all of 1 minute with flashlight.

Auberon · **Posted:** Thu Sep 29, 2016 9:19 am

Just a note about a habit I've gotten into but whenever I do any work fitting new pulley installs of any kind to any marque I use one of the Gates laser alignment checkers. Picked one up for not too many dollars despite the shipping costs and that peace of mind is golden as I'm certain all components are aligned against the crankshaft pulley.

The technology of just a "simple belt drive" had leapt forward in huge quanta even for the years of KJ production and they need to be treated accordingly. I'd agree with the others re the frequency of checking and replacement.

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

Auberon wrote:

Just a note about a habit I've gotten into but whenever I do any work fitting new pulley installs of any kind to any marque I use one of the Gates laser alignment checkers. Picked one up for not too many dollars despite the shipping costs and that peace of mind is golden as I'm certain all components are aligned against the crankshaft pulley.

The technology of just a "simple belt drive" had leapt forward in huge quanta even for the years of KJ production and they need to be treated accordingly. I'd agree with the others re the frequency of checking and replacement.

Personally I have no experience with this tool but if you're using, or thinking of using, one of these devices this thread makes some interesting reading http://www.corvetteforum.com/forums/c5- ... t-way.html

"What many don’t know until it’s too late is that these tools do not come calibrated and they are way off"
"I received my Gates 91006 this weekend and it was off by more than 3/4" over a 2-foot span"

Auberon · **Posted:** Tue Oct 04, 2016 12:57 pm

Thanks for that. Yes indeed the first order of business with any such alignment device is calibration which is not so hard when the instructions are followed.
The sceptic that I am, I too verified it against a known true surface before use and check each time before use. Many sources of error can creep into these things this is merely a method of minimising with proper use the amount of error.

It stands to reason that parallax can introduce errors and there are a myriad of other potential errors but this is why they use the paper as a simple way to calibrate within reasonable tolerances for a belt to run. The eye is the gauging device we are using in every case for such calibrations. It is not aligning the bearings of a 1000 hp main generating set that is 10-15 m c/c and needs to be trued to minute fractions of a minute of angle.

The interesting thing is that the post complains that the paper could be so far off (potentially) but serves to attain reasonable tolerances for the intended purpose.

Given the complexity of engine bays it is the best and most economical methodology I've so-far found to ensure true running of any number of belts and they are running longer by far since I've aligned accordingly.

One could gripe about the optics supplied and the size of the dot or shape of the reticule too.
It is my view and Gates' that the laser as presented gets the alignment within acceptable limits.

It's always a case of caveat-emptor and using sensibly. The days of using a straight edge against a pulleys' edge are long gone (in engine bays anyway). Try fitting one into let alone holding a straight edge in place and measuring offsets to the centre if the reference groove whilst contorting your body in the engine bay.......................with the same degree of accuracy. NAH. Not me.

serpentine belt woes

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