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heat exchanger dry

S

slow cruiser

Regular Contributor
2001 Tiara 3100 8.1 Captain's Choice, full FWC. I'm having an over heating issue on the port engine. Yesterday I popped the end cap on the HE to check for corrosion. I expected water and coolant, but it was dry. Not even a drip. It has sealed shaft coolers so I guess the raw water just drains down into the shaft log. But shouldn't there be coolant in there?
:confused:
By the way there was no corrosion, tarnish but no build up.
 
The heat exchanger has raw water in the part with the end caps. The top of the exchanger where the pressure cap is located should have coolant in that chamber. The dripless shafts should have raw water feed.

It sounds like you have a raw water pump or impeller failure since no water is feeding the heat exchanger. Is the thru-hull opened that feeds the raw water pump?
 
New raw water pump/impeller. Sea cock open, cleaned out the inlet. I think I was wrong about the HE. I opened the drain plug and there is coolant in the HE.
 
Slow Cruiser... please post some photos of your engine, heat exchanger and seawater pump for us.
Pictures are often worth hundreds of words... maybe even more. :D

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I cleaned the inlet, several hitchhikers in there (barnacles). Tubes in both the HE and the oil cooler are clear. Elbows were replaced last year. Temp is almost right. Now i'm going to replace the hoses from the inlet to the raw water pump. The Crusader parts manual shows a fuel cooler between the strainer and the RW pump, but there are none on either engine. That's the whole RW system!
 
Just curious. Does your left engine have more vapor coming out the exhaust than the right engine ? Usually a sign of reduced raw water flow through the system.
 
Yes it does although I had it out today and it's reduced by about half since I cleaned the intake. I'm hoping the new hoses will clear the rest.
 
Lesson learned, hopefully! I had reversed the temp gauges to check if was a bad gauge, same results so I felt the temp was indeed too high. This weekend I got a temp gauge attached to the engine, took a trial run-temp is fine and the same both at the sending unit (ir gun) and the new gauge. Bad sending unit! However, same white vapor out the exhaust. Exhaust elbows on both engines are within 2*. Could the raw water still be the cause of the white exhaust or am I looking at something more serious ie head or intake gasket?
 
My vapor problem was the UTube cooler. Radiator shop cleaned it out ($150) and the problem went away. The coolers are famous for collecting chunks of impeller and anything that makes it through the strainers.
 
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