'08 Liberty in signature. ~154,000 miles. Been solid except for a few niggling Jeep issues, mainly HVAC, which we've had it in for - and warranty work for the same thing- thrice now. Two weeks ago it threw a code for high coolant pressure and we had a new thermostat installed; all was fine after the repair. Then 5 days ago, wife reported no heat - again. All was fine in between, and suddenly the heat was gone. Third time no heat, including new manifold under the dash, associated control panel and two heater core replacements I was away so Mrs JLTD stopped driving it and drove mine, only trip in the Jeep was to get her home and later a couple blocks out and back then the drive to the dealer. So back to the dealer we went, for warranty service. Engine's running fine, except started to overheat on the way to the dealer. Pop the hood @ dealership and engine's dry on top with nothing leaking anywhere. Fast forward 5 hours....get a call and they tell me there's no coolant in the engine and they've done a "carbon test" and figured out that the head gasket is gone. OK I think, I've seen a sudden head gasket failure with no external signs before. But why did it take them 5 hours to see that? I was 2nd in line this morning... Then the service advisor asks, "How much does you wife love this car?". Uh, oh I think. Advisor won't give me the estimate over the phone, says I'll get a texted link. I opened the link and that's when I laughed. Before I get to the engine-- They also recommend full front and rear brake rotor replacement. I just did the brakes around 20k ago, checked 'em during tire rotation (Sept) and the pads are good. It's 12 years old, got some rust on the calipers, which seems to be the major issue they're having. Steering rack leaking and needs to be replaced. Just checked the driveway, again, and no sign of anything leaking. The rack was dry when I was under there in October for the oil change (which will be changed again). Head gasket needs to be replaced, and according to the tech: engine is too old for head gasket replacement, engine needs to be replaced. And he misspelled "too old" writing "to old" instead. [censored] [censored] [censored] [censored] )^#@$% STEALERSHIP. Oh, and they want 10 grand. I am tempted to violence, but instead I'll get it to a nearby mechanic we trust. I realize the vehicle's old and to some extent it's throwing good money after bad. Perhaps it's time to get it repaired well enough to go trade it in.....which may be the whole point of the dealer's whopper of an estimate. /rant Question: I'm not familiar with the Carbon Test. Can anyone enlighten me before I go down the internet rabbit hole?