STB
Guru
Without a doubt, a thorough engine survey is the best thing you can do from a really good surveyor. The best Cat guy in the US is Tim Caruso in Stuart, FL. The cost to have him come is nothing compared to what you will learn about your engines and just as important you will learn how to take care of them. Look at Tim's background from his website which is Marine Diesel Analysts.com. Tim only does Cat Marine Engines and has been doing it for 41 years all over the world.
He did a marine survey for me on a 38' Californian aft cabin with 3208 cats (that had been after-market dual turboed).
He was very thorough. Missed nothing. I backed out. The next week a buyer using another surveyor and inspector did not.
I probably could have negotiated with the reasonable seeming seller for a fair price -- and maybe the next buyer did.
But, the boat was a compromise for me in a few other dimensions, so that just tipped the scale away from it.
At any rate, Tim gets high marks from me. Really high.