mpottorff

I just bought a boat with a pair of 496MAG HO with about 200 hours on them. The pervious owner was a great polisher of the boat but left a little to be desired on maintainance. So right after I bought the boat one of the sea water pumps failed and sent pieces of it into the heat exchanger, I think. When I installed new pumps on both motors I back flushed the lines and heat exchangers as best as I could and got some parts out. Now with new sea water pumps the motor that had the failed pump runs about 15 degrees hotter than the other. I suspect the heat exchanger may have some chunks of the impeller clogging it. Has anyone every taken the heat exchangers apart on one of these motors or had this happen to them? And if so did the clean out fix the issue?
Does one just pull the end cover off the heat exchanger and rod out the core inside?

TWIN-SPINS

you need to clean out the oil cooler...thats where your rubber pieces end up...its on the port side under exhaust manifold

mpottorff

Question.
So if there were water pump impeller pieces in the oil cooler this could block water flow to the heat exchanger and cause to motor to run warm? It looks like the oil cooler on mine will be a real SOB to get to.
I pulled the end caps off of the heat exchanger and rodded out the core but nothing was in there...it was pretty clean.
My oil temp on both motors is about 140 degrees while the water temp on one is 180 and the other is 165. Could my gauges be off that far?

TWIN-SPINS

http://www.teambajamarine.com/forum/...ighlight=temps read this

MOP

It is easier to take the hose off the exchanger and the back of the oil cooler then flush no need to remove the cooler, you need good volume in any case to get the bigger pieces moving. A few chunks will raise the temp quite a bit.

redwenvy

I agree with the previous post. I had the same experience. The impeller pieces settled in the oil cooler. Pull the hoses and back flush with a large volume of water. That should do it for you!