Does Lost serpentine Belt driving=Timing Belt repercussions?

Biosmell · **Joined:** Fri Jan 08, 2010 3:06 pm **Posts:** 32

Good Evening All!

The family and I were Driving home down the coast at night from a friend's when there was a knocking from the front at idle like the fan hitting a piece of loose plastic. Being my wife's daily driver all of my tools beside basics were in my cummins and not on board (although there is actually an extra belt under the back seat). The only light I had on board was my cell phone. Looked at it while off in the dark on the side of the road trying to see if part of the shroud was loose or something. The plastic piece on the bottom of the shroud seemed loose but could not see anything obvious in the cell phone glow. It sounded fine and ran when restarted with an occasional external thump at idle/stops. Went home and put the kids to bed. Next morning I was scheduled to fix the Jeep after I dropped the kids at preschool. Going up a hill approaching a stop at @ 25 mph I heard a slight groan/whine (quiet) and everything stopped. Put on flashers rolled down the hill to a safe spot off the road, opened the hood and the serpentine belt was off and missing about 1/4" in width.

Belt is a Gates about 8 months old replaced with the alternator and new Optima. All pulleys rolled freely. The belt had started to split/peel from the inside edge and an 1/8" thick band had wound itself around the crankshaft pulley. I was a mile from home so I got her back to the driveway via tow put on a new belt. Primed her and now she cranks but won't turn over.

I pulled the camshaft position sensor error code P0340 and thought maybe the belt threads hit a wire but it is on the other (back) side of the engine. Pulled that and will replace tomorrow.

We are due at 100k for the timing belt replacement anyway and I am gathering the parts (ID) and deciding if I want to tackle it or have someone else do it. I turn all of my own wrenches but with wee ones running around my uninterrupted time to focus on a project like this is not what it used to be.

My question is could there be any possible relation or consequence of losing the serp belt while driving that could cause the timing belt to jump and if so does that mean rocker replacement? A mechanic/friend said that the two belts were unrelated and loosing the serp would have no effect on the timing belt but I am not so sure (although by no means as competent as he is).

No noise when I crank besides cranking and trying to catch.

Any thoughts very much appreciated and welcome!

Many Thanks!

PS: Geordi; You coming by the SF Bay Area anytime soon? I know I am a year late on the TB replacement train!

dirtmover · **Posted:** Wed May 20, 2015 7:51 am

I do recall one member having timing belt problems after the serpentine shredded and some of the reinforcement got under the cover. There have also been other suggestions that a timing skip coincided with serpentine failure. I feel that this is very unlikely but can't rule it out 100%. Did you replace the tensioner at the same time as the serpentine?

papaindigo · **Posted:** Wed May 20, 2015 9:43 am

As dirtmover notes it is possible for a serp belt to come loose in whole or in part and jam in such a way as to interfere with crank rotation enough to cause the timing belt to get off. Indeed it's even theoretically possible when that happens for the timing belt to strip enough teeth that the crank shaft and cams are no longer "connected" which clearly could result in a crank but no start.

Thoughts:
1. pm or email geordi as he is headed to points north of you soon and might could fit you in. Do not wait in hopes he sees this post.
2. when you replaced the alternator did you make absolutely sure it came with the appropriate decoupler pulley?
3. I've had a serp belt come off, not on the CRD, as a result of a bad tensioner so as part of whatever you do I'd replace the tensioner.
4. to the extent damage has been done a bit of extra cranking won't do any more so pop oil filler plug on top of the engine and shine a flashlight in there while someone briefly cranks the engine if the camshaft, which you can see thru that hole, does not rotate then the timing belts is busted or stripped. If it does rotate consider pulling the fan and shroud so you can get at the crank nut so you can rotate the engine manually, my main PC is down so I cannot double check rotation direction so best check FSM; pop the 2 bolts that close off the cam alignment holes; manually rotate the engine and see if you can get a cam alignment tool into both cam alignment holes at the same time (you are not setting timing just checking it so drill bits or allen keys can be used); if you cannot the engine is out of time.

geordi · **Posted:** Wed May 20, 2015 12:14 pm

I am currently planning a trip to the San Francisco bay area in addition to potentially the Seattle area - Your Jeep picked a perfect time, if you have a few more weeks to allow for cheaper flight selections.

We can talk more over PM, but you could be looking at a rocker replacement, based on what I have read so far. It seems like better than a decent chance, honestly.

dirtmover · **Posted:** Wed May 20, 2015 12:56 pm

papaindigo wrote:

As dirtmover notes it is possible for a serp belt to come loose in whole or in part and jam in such a way as to interfere with crank rotation enough to cause the timing belt to get off. Indeed it's even theoretically possible when that happens for the timing belt to strip enough teeth that the crank shaft and cams are no longer "connected" which clearly could result in a crank but no start.

I believe this is the member I was thinking about.

"My TB jumped, but it was because the serpinetine came apart slowly and serpentine wires got into the cam gear and caused the slippage."
viewtopic.php?p=852911#p852911

"Somehow the steel from the belt found it s way thru the inner cover to the crank where it caused the timing belt to jump which resulted in a half dozen rocker arm failures."
viewtopic.php?p=847908#p847908

Biosmell · **Joined:** Fri Jan 08, 2010 3:06 pm **Posts:** 32

Thanks all!

I have ben going over Sir Sam's tutorial and video (as I have many times before) trying to covince my wife to let me do it myself as I do everything else on our vehicles.

No one wants to touch something that they have no experience with. I was/am going to rent the tools from GDE (their ecotune was the first thing I did when I purchased the jeep 6 odd years ago). My biggest obstacle to willingly do it myself is that the shop where I formerly had privileges for the last 10 years had the insurance man come down and said they would yank the insurance if they found "non-employees" in the shop. Even after hours so now I have been relegated to the parking lot or pay them the hourly for them to wrench on it if I need a lift.

BTW: when I took it in to the local stealer for a recall replacent of the rear suspension they first thought I had a horrible problem. When I told them it was a diesel they then asked me, "how much did the conversion cost?". With a straight face I told them that it came off the assembly line from the factory that way. "No S##T!".

I then kindly asked for the parts and the key back and left...

geordi · **Posted:** Wed May 20, 2015 11:39 pm

Biosmell - Check your PM, you have a message and an opportunity like none other!

I have a confirmation to the SFO area, and am currently planning the flight for the week of June 8th. If you would like me to work on your CRD, now is the time to jump on board!

Hope to see you in a few weeks?

SargeIndustries · **Posted:** Thu May 21, 2015 2:52 pm

I guess I better change my serpentine belt before this happens to me as well. It is the original and it has 165,000 miles on it.

geordi · **Posted:** Thu May 21, 2015 4:11 pm

Yipes! I really hope your timing belt is a lot younger than that!

The serpentine belt comes in the kit from IDparts, so I usually just install the new one when working on a CRD, but no matter what - over 5 years is too long for any rubber belt to be in service. Over 10 years is just crazy time!

Does Lost serpentine Belt driving=Timing Belt repercussions?

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