Replace Heat Exchanger End Cap

acicomp

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Apr 7, 2016
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I've been working through the systems on the boat to get it ready for water. I noticed a drip coming from the end cap of the heat exchanger, so I pulled the caps off the exchanger today and found a crack on one of the caps. At an initial glance, I thought this would be a 4" system, however, when I measure the cap, it appears to be a 3.75" cap. Being new to the boat world, so to speak, I thought I would ask some folks more knowledgeable than myself. The boat is a 1982 Renken 995 with a 1982 Mercruiser MCM120 (2.5L) motor. This looks to be a possible aftermarket exchanger by the way it is installed. It's strapped to the stern wall on the starboard side of the motor. Can anyone recommend what size caps/gaskets to order for replacement or part numbers I might be able to use here?

Thanks for any help.
 

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Bondo

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This looks to be a possible aftermarket exchanger by the way it is installed.

Ayuh,.... That's gonna make it tough,.... San Juan has alota units out there,...

Any other identifyin' marks on it anywhere,..??
 

acicomp

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Found the tag on the back of the exchanger. It's a Sen-Dure 4987-1-5. Looks like they are still in business, so I may try to call them tomorrow to double check.
 

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FreeBeeTony

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I don't live far from there, Bayshore, NY, and don't think they are around anymore............sorry.
 

Scott Danforth

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sen-dure is still in business. the end cap is brass, can always clean it up and have it brazed (that is what I would do). it is a standard 4" end cap shell of your heat exchanger is 4-1/8", the spider casting sits inside, and the end cap is about 3-3/4" like you measured.
 

acicomp

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Apr 7, 2016
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Thanks for the info. I thought it looked like they might still be open. At least their website was still up and running.
 

acicomp

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Apr 7, 2016
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44
I called Sen-Dure on Monday and got the part number for their end cap. It comes as a kit with new cap, gasket, washer and bolt. They recommended I order from Defender, so I called them up and ordered one for each end to have them both right to start with. Parts arrived today, so I will be installing tomorrow and getting one step closer to finally getting her in the water.
 
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