Exhaust problem lead to blown engine

[disasterinfiniti]

Hi,
I just got handed a different work vehicle, a 2005 QX56 with 155,000 miles. We had it in to the local Infiniti dealer for some work and the service tech told my colleague (in a bit of a whisper) that the vehicle had an exhaust problem which would be prohibitively expensive to fix but if it was not fixed it would lead to a blown engine in another 10-15,000 miles.

I was not there so this is second hand but I can't think of how this could happen, unless the baffling collapsed and restricted flow so much that the exhaust gases couldn't escape. I also can't understand how it could be that expensive to fix. I've searched the site but can't find this issue discussed.
Thanks,

[Ozzie]

Welcome to Nico!
This story sounds weird....
The old "potato in the tailpipe" trick wouldn't destroy an engine.... so I can't see how a collapsed muffler could do it either.
Getting a new exhaust system isn't that expensive..... there are plenty of exhaust shops out there that could build you a sweet custom, hi-flow system for under $800.
Any more to the background story here?
Is the dealer trying to get you to buy a new car, by saying that this one is nearly dead?

Sounds shady to me..... without more details anyway.

[disasterinfiniti]

Thanks. I don't have more information but the idea was strange enough I thought I'd throw it out there in case there was something about this drivetrain I'm unaware of.

[C-Kwik]

I've not heard of anything like this. I doubts its anything to do with a collapsed or restricted exhaust. The only possibility is if it were to have a similar problem to some Sentras where the Catalytic converter would deteriorate and get sucked back into the motor, causing damage. But I have not heard of any problem like this in Titan/Armada/QX56. Exhaust manifold cracks are a common problem in early models, but it shouldn't cause damage...just a hit in fuel economy and low-end power.

[MagicMike]

Could be the common cracked exhaust manifolds issue. Just had mine replaced under warranty.

[Eikon]

Dual exhuast setup on the QX right? Those muffler belts can do some serious damage if they go bad..