Timing Chains at 50k

[harleymonster1]

50k the odometer....check engine light comes on, press on- star.....they tell me the cams are out of timing have it serviced. Check engine light goes out, dealer explains several codes have come and gone but the final diagnostic was not a computer problem but streched timing chains.
This had been an ongoing problem for several months, the first time the light came on it was a gas cap. After several more check engine lights and many on- star chats..(.they all knew me by my first name), finally the dealer figures it out, timing chains have to be replaced.WTF.
Anyone with a similar issue??????

[Panzer Leader]

Not on mine. Most of my past cars were timing belts that were replaced around 100K miles. I have never had to replace a timing chain under these conditions. Never heard of a chain stretching but rather breaking. Another question would be, what happens if it does break. Is it a non interference design or will the valves and pistons be damaged? Normally, when a belt is replaced one would replace the water pump as well. (Since you are there anyway) Please keep us posted on developments.

[Bear]

That's a bummer ! With the modern technology available,engineering ,and testing methods used before the cars start production,it's just not acceptable for a modern car. Have you done any mods, cam,valve springs,etc? That might have contributed to your problem, more load on the valve train could equal more wear on the chain?

[dandragonrage]

Chains DO stretch but 50k seems like way too short a time for it to happen in. Maybe your chain was defective from the factory and thus prone to stretching sooner than it should.

The dealer could also be wrong...

[Sephiroth]

the LS2 Timing chain's service intervale is 150K miles, so no, it should not be common.

And your car does not have cam(s)

it has a single cam.

Maybe your chain was defective from the factory and thus prone to stretching sooner than it should.

This is my guess, or the tensioner was installed incorrectly, or damaged.. ect.

[TomPierce]

Stock timing chain tensioners are prone to failure - usually it does not damage anything in the motor - in fact, it may not even be apparent that the tensioner is broken unless you disassemble the motor for some reason. This could be part of your problem.

http://forum.grrrr8.net/showthread.php?t=21627

[Panzer Leader]

Is this the same setup on the 3.6L V6? This is a V6 engine he is talking about.

[Sephiroth]

Is this the same setup on the 3.6L V6? This is a V6 engine he is talking about.

The LY7 System is much more complicated. OP if you have a LY7, I would not hesitiate to take it into the dealer. Eye spy 7 tensioners and 3 chains in this picture.


you should know! D= you posted in this thread
http://www.g8board.com/forums/showthread.php?p=586251

[Bear]

WOW !!!!!!!! That's just sumthin looooking to come aaaaaparrrrt.

[Sephiroth]

WOW !!!!!!!! That's just sumthin looooking to come aaaaaparrrrt.

The only engine I've seen that's come close to the stupid complicated mess the LY7 represents is a DOHC 40v audi V8. All the chains and tensioners are on the back of the engine(requiring a power train separation) although I'm pretty sure it has only 1-2 chains and 3-5 tensioners/guides. The LY7 still takes the cake seeing as even the GM service manual is littered with inconsistencies in the chain service procedure.