engine overheating - Westerbeke 4-107

[lcad]

<div>Help!!!!!! I have a 1969 Morgan 38 Classic with a real gremlin in
the raw water cooling system. We have cleaned all the lines
several times; had the heat exchanger ultrasonically cleaned;
just had a complete engine overhaul and alas after approximately
25 hours of engine time the gremlin reared its ugly overheating
head again. This has been one of those wonderful intermittent
problems. I am suspecting there must be a design flaw in the
plumbing that is somehow creating a "vapor lock" for lack of a
better explanation. Any ideas out there?
</div>

 

[dennstap]

Have you checked the exhaust wet manifold. I dont believe that there is any mention in any manual about the fact that over time the passages become occluded. After 18 years and 600 hours I was getting some steam into my exhaust. I removed the wet exhaust manifold and found it to be about 40% blocked. I had it boiled out and pressure tested and no theres no more steam and I dropped about 20 degrees in engine temp.

 

[hokalea]

I was just passing by when I noticed your problem. If there is a blockage or leak, you obviously need to find and fix it. Beyond that, consider changing coolant. I roadraced motorcycles for a full season ('99) using Evans brand NPG coolant. There are lots of reasons why it's better, but a quick run through would go like this. It is non-toxic, NON-CORROSIVE, and lasts the lifetime of the vehicle. The boiling point is 370 F at ambiant pressure, which keeps hot spots from developing which in turn means no detonation. The system can run with little or no pressure (low press. radiator caps are available) relieving a lot of the stress on rubber parts. Look up the company at evanscooling.com ;it really works like they say. We had no problems on a weekend in Georgia when the temperature was above 100 F. Many other bikes there that weekend seized due to the heat, we had no problems. -John.