My cd28 sail is overheating. I think it is time to replace the thermostat just to eliminate one variable of why. How big of a job is this? Are there any special tools and what else should I do while I am in there?
Thanks for you help...
Thermostat
Moderator: Jim Walsh
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Chris Reinke
- Posts: 179
- Joined: Apr 14th, '05, 14:59
- Location: CD330 - Innisfail (Gaelic for "A Little Bit Of Heaven on Earth"), Onset, MA
Checking the thermostat is really not a big deal and you should be able to do it yourself. It would be helpful to know what type of engine you have to provide some specific information.
Testing a thermostat is very easy once you remove it. Just put it in some boiling water and see if it opens....or just replace if that will provide some peace of mind.
Can you offer any more information as to when your engine is overheating:
- is it reaching critical temps very quickly under minimal loads
- is it just running hotter then usual, but still within the safe zone
- do you have good water flow out your exhaust (water pump issue, partially obstructed raw water intake, etc.)
- do you have coolant leaks, blockages, etc.
The more information you can provide on your observations and engine type will certainly get you better feedback from the more knowledgeable folks on this board... I am just a student.
Testing a thermostat is very easy once you remove it. Just put it in some boiling water and see if it opens....or just replace if that will provide some peace of mind.
Can you offer any more information as to when your engine is overheating:
- is it reaching critical temps very quickly under minimal loads
- is it just running hotter then usual, but still within the safe zone
- do you have good water flow out your exhaust (water pump issue, partially obstructed raw water intake, etc.)
- do you have coolant leaks, blockages, etc.
The more information you can provide on your observations and engine type will certainly get you better feedback from the more knowledgeable folks on this board... I am just a student.
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Neil Gordon
- Posts: 4367
- Joined: Feb 5th, '05, 17:25
- Location: s/v LIQUIDITY, CD28. We sail from Marina Bay on Boston Harbor. Try us on channel 9.
- Contact:
Re: Thermostat
Is this an MD7A? If so, it's straightforward and you just need the right size wrench. Watch for the seals... they're not easy to find at retail.
You might find accumulated slime/sludge when you open things up. Clean what you can but don't push any potential clogs deeper.
You're getting water out of the exhaust? If not, the thermostat isn't the (only) problem.
You might find accumulated slime/sludge when you open things up. Clean what you can but don't push any potential clogs deeper.
You're getting water out of the exhaust? If not, the thermostat isn't the (only) problem.
Fair winds, Neil
s/v LIQUIDITY
Cape Dory 28 #167
Boston, MA
CDSOA member #698
s/v LIQUIDITY
Cape Dory 28 #167
Boston, MA
CDSOA member #698
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jerryaxler
- Posts: 271
- Joined: Feb 13th, '05, 14:10
- Location: Cape Dory 36, Shana, Rock Hall, MD
overheating
I just went thru the same process. You can remove the thermostat and run the engine under load at your slip and see if that does the trick. When replacing the thermostat housing a new gasket will probably be necessary. If you have good raw water flow then it could be the heat exchanger is partially clogged or the circulating pump is not working properly.
My problem was a combination of a partially clogged heat exchanger and a false reading of the heat sensor. Your mechanic can measure the actual temperature with a thermometer into the coolant with a sealed pressure cap.
Good Luck
My problem was a combination of a partially clogged heat exchanger and a false reading of the heat sensor. Your mechanic can measure the actual temperature with a thermometer into the coolant with a sealed pressure cap.
Good Luck
Fairwinds and following seas,
Jerry Axler
Jerry Axler
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Oswego John
- Posts: 3535
- Joined: Feb 5th, '05, 20:42
- Location: '66 Typhoon "Grace", Hull # 42, Schooner "Ontario", CD 85D Hull #1
Thermostat
VidaliA,
Chris, Neil and Jerry gave you some good advice. There is another thing I sometimes do to check a thermostat.
After removing the thermostat, I place it in a pot of cool water, not boiling water. I also place an immersion thermostat in the pot.
Thermostats come in a variety of temperature settings to help determine what temperature a person wants his engine to run. For sake of argument, lets say that the thermostat is set for opening at 180 degrees F., a common type. The numbers 180 will be stamped on the thermostat.
As the water heats in the pot, you will be able to observe the water temp. As the water temp reaches (approximately) 180 F, you should be able to see the thermostat physically open up. As the heat is turned off and the water cools, you should notice the thermostat close.
This method helps you determine if the thermostat is functioning properly at the temperature it was intended for.
Good luck,
O J
Chris, Neil and Jerry gave you some good advice. There is another thing I sometimes do to check a thermostat.
After removing the thermostat, I place it in a pot of cool water, not boiling water. I also place an immersion thermostat in the pot.
Thermostats come in a variety of temperature settings to help determine what temperature a person wants his engine to run. For sake of argument, lets say that the thermostat is set for opening at 180 degrees F., a common type. The numbers 180 will be stamped on the thermostat.
As the water heats in the pot, you will be able to observe the water temp. As the water temp reaches (approximately) 180 F, you should be able to see the thermostat physically open up. As the heat is turned off and the water cools, you should notice the thermostat close.
This method helps you determine if the thermostat is functioning properly at the temperature it was intended for.
Good luck,
O J