Westerbeke 27 overheating troubleshoot

[Mutt]

Hello Russian 007

Hot water tank is the thing that makes hot water for the galley. On some boats the emgine coolant is used to heat this water. There will be a hose from the exhaust manifold jacket to the tank and another back. This is not installed on all boats.

[rognvald]

Originally Posted by captstu

Heat exchangers are one of several weak spots on a W'beke. Did you pull the end caps and back flush the exchanger? If not, you may want to remove it and have it washed/cleaned by a radiator shop.

Good advice. You can clean many heat exchanger tubes with a long handle wire bristle brush available from many vendors online. This is how I cleaned mine last time with a mild solution of muriatic acid and, then, thoroughly rinsing with distilled water. I would suggest you replace the gaskets before reassembling. Good luck and safe sailing.

[jimbunyard]

Originally Posted by DeepFrz

Antifreeze mixture transfers heat better than water alone. When you have your heat exchanger off, check the injection elbow to make sure it isn't blocked. Might as well check your anti siphon valve while you are at it.

Edit:
Antifreeze also acts as a corrosion inhibitor. Make sure you get the kind recommended for your engine.

Actually, water alone is significantly better at heat transfer. Antifreeze lowers the freezing point of water, increases the boiling point, and provides corrosion protection and lubrication.

If you don't need antifreeze, don't use it, but you should run some type of additive for corrosion protection and lubrication.

[jkishel]

Please do not continue to arbitrarily replace components. Instead, systematically evaluate the problem. First, it appears that the engine is running hot, although it hasn't actually overheated yet. Also, it appears that you aren't losing fresh water coolant. If so, start with the raw water system. Check that the through hull, hoses and strainer are all clear. Check that the heat exchanger is clean. Then check that the mixing elbow is clear. If all that stuff is good you should have a strong flow of cooling water. If not, look at the raw water pump. You say you replaced the impeller, then check the face plate and gasket. If there is strong cooling water flow at the stern and the problem persists, turn to the fresh water system. You say you've replaced the fresh water pump and thermostat. As long as the drive belt is tight and the radiator cap is good, the engine should not overheat.

[Russian007]

Originally Posted by Mutt

Hello Russian 007

Hot water tank is the thing that makes hot water for the galley. On some boats the emgine coolant is used to heat this water. There will be a hose from the exhaust manifold jacket to the tank and another back. This is not installed on all boats.

I'd like to have one of those.

[Russian007]

Originally Posted by jkishel

Please do not continue to arbitrarily replace components. Instead, systematically evaluate the problem. First, it appears that the engine is running hot, although it hasn't actually overheated yet. Also, it appears that you aren't losing fresh water coolant. If so, start with the raw water system. Check that the through hull, hoses and strainer are all clear. Check that the heat exchanger is clean. Then check that the mixing elbow is clear. If all that stuff is good you should have a strong flow of cooling water. If not, look at the raw water pump. You say you replaced the impeller, then check the face plate and gasket. If there is strong cooling water flow at the stern and the problem persists, turn to the fresh water system. You say you've replaced the fresh water pump and thermostat. As long as the drive belt is tight and the radiator cap is good, the engine should not overheat.

Oh no, the fresh water pump was shot as was the impeller. Thermostat was a shot in the dark. It was only $19 so I figured why not.

UPDATE: Today did the following:
1) bled air out of the coolant reservoir. Coolant level dropped immediately so that suggests an air lock.
2) tightened belt. There was more than 1/2" of play so tightening I think helped.
3) the nipple that connects to the coolant overflow was totally blocked/clogged with scale. I picked away to free it.
4) took the caps off the ends of the heat exchanger, a coup of the vanes/tubes were blocked. see photo I did my best to open them up. I found bits of the old impeller and some sediment. see photo
5) started her up and she didn't overheat! So right about now I'm feeling pretty smart and all mechanical and stuff.
Got so questions still.
a) is a hand drill the best way to open the blocked heat exchanger tubes? the sediment is tough to pick through.
b) Even though I flushed the fresh water system a few days ago with store bought flushing liquid, the water going into the coolant overflow tank looked terrible. Very brown. Recommendations for a good coolant flush brand?
EDIT: dunno how to add photos, check here for HX shots and the sediment I found in the HX. https://www.facebook.com/angelmanket...type=3&theater

[Russian007]

Originally Posted by jkishel

Please do not continue to arbitrarily replace components. Instead, systematically evaluate the problem. First, it appears that the engine is running hot, although it hasn't actually overheated yet. Also, it appears that you aren't losing fresh water coolant. If so, start with the raw water system. Check that the through hull, hoses and strainer are all clear. Check that the heat exchanger is clean. Then check that the mixing elbow is clear. If all that stuff is good you should have a strong flow of cooling water. If not, look at the raw water pump. You say you replaced the impeller, then check the face plate and gasket. If there is strong cooling water flow at the stern and the problem persists, turn to the fresh water system. You say you've replaced the fresh water pump and thermostat. As long as the drive belt is tight and the radiator cap is good, the engine should not overheat.

Oh no, the fresh water pump was shot as was the impeller. Thermostat was a shot in the dark. It was only $19 so I figured why not.

UPDATE: Today did the following:
1) bled air out of the coolant reservoir. Coolant level dropped immediately so that suggests an air lock.
2) tightened belt. There was more than 1/2" of play so tightening I think helped.
3) the nipple that connects to the coolant overflow was totally blocked/clogged with scale. I picked away to free it.
4) took the caps off the ends of the heat exchanger, a coup of the vanes/tubes were blocked. see photo I did my best to open them up. I found bits of the old impeller and some sediment. see photo
5) started her up and she didn't overheat! So right about now I'm feeling pretty smart and all mechanical and stuff.
Got so questions still.
a) is a hand drill the best way to open the blocked heat exchanger tubes? the sediment is tough to pick through.
b) Even though I flushed the fresh water system a few days ago with store bought flushing liquid, the water going into the coolant overflow tank looked terrible. Very brown. Recommendations for a good coolant flush brand?
Can't add pics of the hx, try here https://www.facebook.com/angelmanket...type=3&theater

[rognvald]

"a) is a hand drill the best way to open the blocked heat exchanger tubes? the sediment is tough to pick through." Russian007


Did you read post #17???

[Russian007]

Originally Posted by rognvald

"a) is a hand drill the best way to open the blocked heat exchanger tubes? the sediment is tough to pick through." Russian007


Did you read post #17???

Yes but no way a wire brush can do it. The sediment is almost like concrete.

[rognvald]

Originally Posted by Russian007

Yes but no way a wire brush can do it. The sediment is almost like concrete.

Russian,
That's why you use the diluted solution of muriatic acid and distilled water. Let the tube sit in the solution for 10 minutes. Check the blockage. If it isn't soft, increase the amount of acid. Repeat process until wire brush removes the sediment. Hope that helps.

[ebsail]

Hot water tank stores hot water for your faucet, if you have a hot water system.

[Russian007]

Originally Posted by rognvald

Russian,
That's why you use the diluted solution of muriatic acid and distilled water. Let the tube sit in the solution for 10 minutes. Check the blockage. If it isn't soft, increase the amount of acid. Repeat process until wire brush removes the sediment. Hope that helps.

Okay so dunk the entire heat exchanger in a diluted solution?

[Russian007]

Originally Posted by ebsail

Hot water tank stores hot water for your faucet, if you have a hot water system.

I barely have that in my house!

[rognvald]

Originally Posted by Russian007

Okay so dunk the entire heat exchanger in a diluted solution?

No,
Pull the heat exchanger tube assembly and soak THAT in a diluted muriatic acid and distilled water solution to loosen the sediment/calcification in the tubes. Try a 10% solution initially and watch for bubbling in the tubes which will show the solution is breaking up the sediment. Your heat exchanger housing is probably fine however, you can check that after the tube assembly is removed. Hope that helps.

[Russian007]

Originally Posted by rognvald

No,
Pull the heat exchanger tube assembly and soak THAT in a diluted muriatic acid and distilled water solution to loosen the sediment/calcification in the tubes. Try a 10% solution initially and watch for bubbling in the tubes which will show the solution is breaking up the sediment. Your heat exchanger housing is probably fine however, you can check that after the tube assembly is removed. Hope that helps.

okay thanks. I didn't realize the assembly was removable.