My starboard engine is running 30 degrees warmer than port and coolant has turned a dark dark rust color after only operating engine for 1 hour or less.

We flushed entire system before re-installing engines.

Mech thinks there is "crap" in tubes inside heat exchanger.

Anyone have clue as to problem and cause?

Is it safe to use auto radiator flush on this system or does the exchanger need to be removed and be rodded and/or rebuilt.

Thanks

Poorsche

www.boatmat.com

I had a heat exchanger on my big boat running 20 degrees higher. Took it off, dumped it in a bucket of CLR for about and hour and then rinsed it clean. Runs exactly the same as the other now and didn't look really crusty when I took it out.

Can anyone tell me proper running water temp on a scarab with 454's? Also--what temp thermostats ------considering water pressure. ?
I've heard of drilling 3--3/16th holes in the thermostats to relieve pressure and allow warm up. Thanks----john