Well I am not a lawyer but I would agree with the new mechanic. Also, it would be really easy to have the oil that came out tested to demonstrate that the "other" chemicals were in there. I would tell you to record him but?
As far as years in operation and racing, big deal, I have done both as well and seen more than a few people who ran shops and had race cars that I would not let change a light bulb.
Mess ups like this are why shops are insured, either to cover the oops moments of the guy who trips and runs a tool down the side of that nice Cadillac, or to repair an engine that a poorly thought of idea wiped out.
I would also agree that the engine would need to be removed, opened up and at the very least new gaskets and a cleaning. Or go after them to install a re-manufactured engine. Your choice on that.
Sorry on behalf of the shops I know who stand behind their work, that you found one who will not.
Saturday, October 21st, 2017 AT 12:42 AM