I think I'm about to get a screweding.
 

I'll try to keep this short. My daughters 2002 Mazda tribute with 90K miles had a catastrophic engine failure. I suspect a bent valve that took out the drive trane and bent a piston rod. The engine is toast. Got it towed to a Mazda dealer. A new engine just isn't worth the expense as I bought the car for $7000 and new engine is north of $5K. The dealer said they could find a low mileage used engine and do the job for $3K so that's the direction I went. The dealer called me and said they had found an engine with 49K miles so I gave them the go ahead. They called me and told me I could pick it up. When I arrived, the service manager walked me out tot he car. He said he had to replace a crank seal. He started the engine and it had a notable tick in the valve trane until it warmed. One of the 6 coil packs had a broken retainer and there was a oil patch on the ground below the engine. There was aslo a pretty heavy mist of oil on the lower part of the upper intake plenum and I found a large bolt simply sitting on top of the valve cover. It was a frame type or motor mount looking bolt. I asked if the machanic who worked on it was there but they said he left the dealer.

When I asked for proof of the engine mileage, he said they didn't get that information from the engine supplier. ??really?? I asked him to replace the cracked coil mount and he said that he'd have to charge me. When I insisted, he said he would replace and call me later to come back. I never got a call.

So now I'm left to simply trust that the engine has 49K miles and completely suspect of everything I'm seeing. As it stands, I will be insisting that I get a VIN of the car it came out of. I can match this to the engine, correct? should have match last digits to engine numbers? What's to stop them from throwing in some stop-leak or some thick-as-paste oil to quiet down the valves? Is there anything I can do to protect myself? No payment has been made but I did authorize the work. Looking for advice from my fellow members here.

It is not unusual for a Repair Garage to obtain take out engines from Auto Recyclers. They may be local to you or actually quite some distance away. Generally the supplier guarantees the engine to the garage to be in good running condition, they are usually started and run for a short time on a pallet before they are shipped. The supplier attempts to verify oil pressure and no unusual noises but when doing so do not generally have any mufflers. They play the percentages, as does the garage. If there is an issue the supplier will replace the engine but there wont be any re-imbersment for labor to pull it out again so you may get resistance from the garage, because it's on their dime. Stand your ground. The suppliers generally provide mileage info with the bill of sale to the garage.

I agree. Stand your ground. His only leverage is the car itself and he likely doesn't want the car.

Did he give you any kind of written estimate that you signed off on (verbal or written) which might have stated a scope of work or his intent to repair?

A repair estimate is a two way street and often Terms and Conditions heavily favor the garage, but it could protect you to some extent that he must perform "x" to receive "y".

The tick could be normal. Figuring the engine was around a 2002 model, with 49k miles, it would have probably sat a long time. It may take a few days of driving for the tick to go away assuming it is a lifter or something similar.

I doubt he will give you any info on where he got the engine. There is a 3.0l with 49k miles on car-parts in North Carolina for $2000. They charged you $1000 roughly to install the engine etc. That sounds about right although I don't have a book to look at "book" time. You basically bought the engine "as is". Unless it is trashed, they generally do not fix stuff without charging you. Stuff that is broken should have come off your old engine.

Where I used to work, if you bought used, it was a pass through on price. We only charged labor. Unless it didn't work when we initially installed it, you bought the engine from the recycler as is. If it blew up 4 months later and the recycler warranty ran out, you were stuck.