What Gorn was getting at, and I was skeptical about too, is that given the time frame, they must not have "tore apart the engine to check for internal damage". That would require yanking the engine, taking it all apart, and rebuilding it. If they just peeked under the intake manifold, that's a far cry from tearing it apart. You can't inspect the integrity of all the bearings, rings, and the rest of the rotating assembly without completely dismantling the engine. At that point, you'd be looking at a rebuild. That didn't happen.

 

I wasn't thinking that's what they did. He told me they took off the manifold and heads, and everything seemed ok. That's why I said I'm not holding my breath on this just yet

 

have a look at the motor and see if the gaskets you can see look freshly replaced.

 

Just the headgaskets alone is a 8-10 hour jobs and would cost $125 in parts. A head gasket job is close to $1200. Assuming there is no issues removing the exhaust manifolds. Checking for internal damage would require a really good mechanic a good 20-25 hours and you would have had 300-400 just in seals and gaskets that HAD to be replaced.

Oh, if he did the head gaskets he would have had to send the heads to a machine shop to get check for cracks. That is a one or two day process. My bet is the heads have not been off. Getting a v6 head gasket job done in 24 hours is almost impossible even if he had no other work and was just waiting for a car to come in.