It's a Jeep thing - timing chain failure on 2020 JLU, 4600km

[b1er]

So this thing was running (poorly) when it was picked up by a flatbed(?) and they told you the timing chain snapped? Nope, if the chain broke, the engine stops right then... Jumped a tooth or 2, maybe it'll run but not likely... if it snapped there's major damage in there (bent valves, damaged rockers dented pistons). They can borescope the cylinders and see if the valves hit... if it really broke the chain, they hit, no way around it. When that happens , the engine will stop dead while making expensive noises.

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[Dono]

So this thing was running (poorly) when it was picked up by a flatbed(?) and they told you the timing chain snapped? Nope, if the chain broke, the engine stops right then... Jumped a tooth or 2, maybe it'll run but not likely... if it snapped there's major damage in there (bent valves, damaged rockers dented pistons). They can borescope the cylinders and see if the valves hit... if it really broke the chain, they hit, no way around it. When that happens , the engine will stop dead while making expensive noises.

Hmm - the 3.6L has multiple chains. One per bank, one for the oil pump and a 4th I'm not sure about. Are you sure it wouldn't still run *very poorly* - anyway, referencing this thread with the service manager just to make sure.

 

[Nickp01]

Yeah this isn’t really a Jeep thing, just new vehicle thing. There will always be defects.

Agree with the above. I would push for a new engine or if they refuse that they better warrantee it for 100k+ miles.

 

[Jamrock]

It is possible for you to escape damage when a timing belt breaks. However, I would get a second opinion.

I would need to get something in writing in case related issues arise during the warranty period. I would want those to be covered by the warranty.

 

[xray]

There is always Lemon Law. This is a pretty catastrophic failure early on. Usually people use lemon law for persistent problems that the dealer can’t fix.

 

[Dono]

There is always Lemon Law. This is a pretty catastrophic failure early on. Usually people use lemon law for persistent problems that the dealer can’t fix.

There's no lemon law in Canada, and this is only the first issue. Going to have to hurry up and wait.

 

[srt20]

They have to take the head off... at the very least! Doing a Compression test seems like a cop out...

you need verifiable evidence that the valves didn’t contact the pistons.

if they don’t take the head off and you leave with the Jeep they are off the hook! I would start pushing and contact @JeepCares

I disagree. Boroscope and Leak down will tell everything that is needed to know.
I don't know how many chains the 3.6 has or what they all run, but if the engine was still running, at the very least one bank was still intact.

Im not a fan of dealerships in any way shape or form, including the repair shops. But it is what it is, and I wouldn't worry to much about it. The 3.6 has a stellar reputation. You got unlucky and got a bad chain. They'll fix it, and life goes on. If there is any issues, its documented that they repaired whatever is broke.

Its pretty hard to sneak a bent valve past a customer....

 

[Dono]

I disagree. Boroscope and Leak down will tell everything that is needed to know.
I don't know how many chains the 3.6 has or what they all run, but if the engine was still running, at the very least one bank was still intact.

Im not a fan of dealerships in any way shape or form, including the repair shops. But it is what it is, and I wouldn't worry to much about it. The 3.6 has a stellar reputation. You got unlucky and got a bad chain. They'll fix it, and life goes on. If there is any issues, its documented that they repaired whatever is broke.

Its pretty hard to sneak a bent valve past a customer....

This is what the service manager said. Made sense. It'll be documented, and the delay is because the new tensioners are out of stock.

 

[Yellow Cake Kid]

Is there is a practical way to test the compression of each cylinder with a broken timing chain.

It seems like a chain would have to be installed with the crank and cam shafts oriented in proper synchronization before you can make an informed observation.

I would feel obliged to expect a tear down with an actual and complete inspection.

It would be interesting to learn of FCAs official protocol with regards to authorizing dealers to perform this sort of inspection in a warranty scenario.

It would also be interesting to compare the warranty protocol with the service guidelines for an out of warranty repair instigated by the same part failure.

 

[b1er]

Hmm - the 3.6L has multiple chains. One per bank, one for the oil pump and a 4th I'm not sure about. Are you sure it wouldn't still run *very poorly* - anyway, referencing this thread with the service manager just to make sure.

Good luck to you... hope it works out.

 

[srt20]

Is there is a practical way to test the compression of each cylinder with a broken timing chain.

It seems like a chain would have to be installed with the crank and cam shafts oriented in proper synchronization before you can make an informed observation.

I would feel obliged to expect a tear down with an actual and complete inspection.

It would be interesting to learn of FCAs official protocol with regards to authorizing dealers to perform this sort of inspection in a warranty scenario.

It would also be interesting to compare the warranty protocol with the service guidelines for an out of warranty repair instigated by the same part failure.

Yes, its called a Leak down test. Much more accurate than a compression test.

 

[srt20]

In a leak down test, all valves are backed off. Its just the valves in the heads with the springs. They are as closed as they will ever be. You pump the cylinder full of air and measure how much leaks out of the cylinder.

I doubt the dealer even wasted time with a compression gauge. A leak down test is much more precise.

 

[Dono]

Dealer says back ordered tensioner arrived today, should have it back together today/tomorrow and get it back this week. Way better than the initial two week estimate

 

[BadAssBumbleBee]

Dealer says back ordered tensioner arrived today, should have it back together today/tomorrow and get it back this week. Way better than the initial two week estimate

That's great news!

Fingers crossed that there wasn't any other damage done to the motor.

 

[DaltonGang]

Interesting. I am very curious how they can do any compression tests, with a non-running engine, with a broken timing chain. Sounds like a BS answer, to pacify you. If I were you, before taking you keys(fob) back, I would do a real good listen for any ticking sounds, with the hood up. Then go for a drive, with the service guy riding shotgun. On the drive, redline it a few times, and listen for any unusual noises, especially at idle. Then do another good listen for sounds, with the hood up.
Also, ask for an extended warranty on the engine.

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