I have one of the Mr. cool replacement heat exchangers, copper nickel. The good thing about these is that you can service both ends as they have removable caps at each end. Is it theoretically possible to remove the cap at the far end and run the engine and flush the water into a bucket thus cleaning out any debris that way or is that a crazy idea? (I am thinking that if I don’t get consistently good water out the exhaust next time I go out, I would take a hard look at the heat exchanger and the possibility of debris.)
Overheat adventure on 1985 Universal M12
- Thread starter odaydokay
- Start date
Some think it impedes electrical continuity between the anode and the HX. Others say the threads will cut the tape enough to make electrical contact.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 24,602
As you state, “It needs a proper ground from its threads to the exchanger”
The threads provide that electrical link as the exchanger should be connected to the engine, and thus to ground.
Teflon tape is there to reduce the chance of leaking. If there is no leak (and there should not be based on the type of threads used for the zincs and exchanger), then no need for the tape. If there is a leak, check and clean the threads.
Fun Fact: Teflon is used on some electrical wires as electrical insulation. It helps to reduce the smoke should a wire overheat.
The threads provide that electrical link as the exchanger should be connected to the engine, and thus to ground.
Teflon tape is there to reduce the chance of leaking. If there is no leak (and there should not be based on the type of threads used for the zincs and exchanger), then no need for the tape. If there is a leak, check and clean the threads.
Fun Fact: Teflon is used on some electrical wires as electrical insulation. It helps to reduce the smoke should a wire overheat.
Irrespective if there are breaks in the threads, it will always have greater electrical isolation between the anode and the threaded hole. You do not want that in this application. @sailme88 is spot on - do not use Teflon tape.
dj
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Sorry that I am late to this party.
The thermostat has nothing to do with this.
I have had a similar problem after the first run of my engine (M25) after the launch of my boat. The problem is that you can get a stubborn air bubble in the raw water circuit. It can be stubborn enough that the vanes in the raw water pump cannot develop enough suction to get the pump primed. What you did in opening the pump, LUBRICATING IT (I use dishwashing liquid soap - I coat each vane, then use the bottle to give the pump a squirt), and then closing the pump back up, solved the problem. Hopefully, you are running the "new" style Oberdorfer pump that has an O-ring, rather than the old type that used a gasket.
Also, be careful if you ream out the old H/X. Some of the holes/pipes DO NOT GO ALL THE WAY THROUGH the H/X. If you push it, you will cause a leak in the H/X, and have to find a boiler repair shop (yeah - good luck with that), or buy a new Heat Exchanger.
Also, the 3" x 13" long H/X is ALWAYS an upgrade to the 2" x 16" L heat exchanger. The 3" has removable end caps, and the 2" does not. I once sold someone a perfectly good 2" x 16" heat exchanger to replace the M12 - a 2" x 12"L spec'd for the M12. The guy returned it, and I gave him his money back, because he stated that it wasn't "supported" which it technically wasn't. It was 4 inches longer, and provided extra cooling capacity compared to the 12". The guy felt that the engine would run too cool, which was incorrect. The engine temperature should be controlled by the thermostat.
The thermostat has nothing to do with this.
I have had a similar problem after the first run of my engine (M25) after the launch of my boat. The problem is that you can get a stubborn air bubble in the raw water circuit. It can be stubborn enough that the vanes in the raw water pump cannot develop enough suction to get the pump primed. What you did in opening the pump, LUBRICATING IT (I use dishwashing liquid soap - I coat each vane, then use the bottle to give the pump a squirt), and then closing the pump back up, solved the problem. Hopefully, you are running the "new" style Oberdorfer pump that has an O-ring, rather than the old type that used a gasket.
Also, be careful if you ream out the old H/X. Some of the holes/pipes DO NOT GO ALL THE WAY THROUGH the H/X. If you push it, you will cause a leak in the H/X, and have to find a boiler repair shop (yeah - good luck with that), or buy a new Heat Exchanger.
Also, the 3" x 13" long H/X is ALWAYS an upgrade to the 2" x 16" L heat exchanger. The 3" has removable end caps, and the 2" does not. I once sold someone a perfectly good 2" x 16" heat exchanger to replace the M12 - a 2" x 12"L spec'd for the M12. The guy returned it, and I gave him his money back, because he stated that it wasn't "supported" which it technically wasn't. It was 4 inches longer, and provided extra cooling capacity compared to the 12". The guy felt that the engine would run too cool, which was incorrect. The engine temperature should be controlled by the thermostat.
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