Engine over heating

[dorydaze@comcast.net]

HELP!! I have a cd 28' power w/ a 165 Volvo diesel eng. that at idle it's ok but when you give it fuel it over heats. I have checked all the seacocks, impeller, changed the thermostats and radiator cap.

I have turned it over to a mechanic; It appears when the rpm's are turned up the anti freeze is pushed out through the radiator cap. Yes there is raw water coming out the exhaust pipe. He has checked the heat exchanger, impellers, seacocks and water pump (everything outside the engine). He is doing a test tomorrow to determine if it's it a cracked head or head gasket
Thanks
Phil


Thanks all who helped. The over heating turned out tobe the oil cooler, with help from the heat exchanger and after cooler.
[/b]

[barfwinkle]

Have you checked to see if the h20 pump is putting out?

Good Luck

[Oswego John]

As Bill suggests, check your water pump. Check for a broken impeller blade(s). Not only will a defective impeller push less water, but the broken blade(s) can possibly create a log jam that restricts water flow. Enough water might pass to keep the engine cool at idle or low RPM but not enough water passes through to cool at higher RPMS

Another thing to check is the external hull water intake fitting. It's possible for it to get clogged up with cabbage, barnacles, zebra mussels or other marine growth. In a rare instance, even clear plastic can get sucked into the system.

Sorry, I just reread the original post and saw that you did check the impeller. Ooops.

Good luck,
O J

[Domenic]

Had the same problem on my mom and dads trawler. Buzzer went off at high rpm . It was a faulty heat gauage. Try changeing the sensor and heat gauage.

[Chris Reinke]

Before you spend any money on replacing items you should take a moment and check a few things and report your findings back to the board. Then the other more knowledgable folks then I, can offer more direct guidance.

1 - Check to see that you have raw water being discharged out exhaust

2 - Determine the amount of water is appropriate. If you have a partially torn impeller then you may get some water movement, but not sufficient to cool.

3 - CAREFULLY - use your hand to check the temperature of the discharged water to see if the temperature gauge reading appears accurate.

4 - If the raw water is remains cool and is moving OK then your problem may be a clogged heat exchanger or something worse on the coolant side of the system.....I am assuming you have already checked your coolant level.

Just trying to gather as much information as possible to help narrow down the problem without sending you in 12 different directions.

[Oswego John]

Chris,

I agree with you 100%. Many times people write in with a problem but only give a general idea of what the problem is.
It's something like talking to a doctor on the phone. The more info you can give him, the better the diagnosis will be.

Quite often, interested readers ask for more info but the poster doesn't respond. There is a wealth of knowledge and practical experience on this board and the members are only too happy to pass on any tips or methods to aid their fellow sailors.

If someone asks you to get back with more in-depth data, it is probably because he needs a little more info in a certain area to pinpoint what the problem might be. Sometimes, the info asked for might seem totally insignificent to the poster, but the answer just might provide the very clue(s) that will answer the problem with certainty.

Best regards,
O J

[Bill - Dulcie]

Chances are if the water is flowing freely out your exhaust at idle, it is passing freely through the heat-exchanger. I wrestled with overheating of a TMD-40A for six months before I discovered that the previous owner had, at some time in the past, let the impeller deteriorate to the point that a blade tore off and lodged in the cooling water pipe, restricting the flow to the pump. When I went looking, I found the old impeller blade in the pipe on the INPUT side of the SALT-water pump - that is, between the raw water strainer and the pump. You might check that first. The broken-off blade was doing exactly what you described - restricting the flow at higher RPMs under load - in this case, the flow TO the SALT-water pump.

You might also check to ensure that your belts are tight to specs. If they are not, they have a tendency to slip at cruise and WOT. Since the FRESH-water circulation pump is belt-driven, the result will be diminished circulation of coolant within the engine and the consequent alarm activation.

Hope I've helped. Been there. Bill - Dulcie

[Ed Haley]

Your thermostat may not be opening when it should. If other things check out, see if your thermostat will open in a pan of heated water with a thermometer to see the temp that it opens. Chances are your thermostat is not opening. Common problem.

[dorydaze@comcast.net]

Before you spend any money on replacing items you should take a moment and check a few things and report your findings back to the board. Then the other more knowledgable folks then I, can offer more direct guidance.

1 - Check to see that you have raw water being discharged out exhaust

2 - Determine the amount of water is appropriate. If you have a partially torn impeller then you may get some water movement, but not sufficient to cool.

3 - CAREFULLY - use your hand to check the temperature of the discharged water to see if the temperature gauge reading appears accurate.

4 - If the raw water is remains cool and is moving OK then your problem may be a clogged heat exchanger or something worse on the coolant side of the system.....I am assuming you have already checked your coolant level.

Just trying to gather as much information as possible to help narrow down the problem without sending you in 12 different directions.

I have turned it over to a mechanic; It appears when the rpm's are turned up the anti freeze is pushed out through the radiator cap. Yes there is raw water coming out the exhaust pipe. He has checked the heat exchanger, impellers, seacocks and water pump (everything outside the engine). He is doing a test tomorrow to determine if it's it a cracked head or head gasket.

[dorydaze@comcast.net]

Chances are if the water is flowing freely out your exhaust at idle, it is passing freely through the heat-exchanger. I wrestled with overheating of a TMD-40A for six months before I discovered that the previous owner had, at some time in the past, let the impeller deteriorate to the point that a blade tore off and lodged in the cooling water pipe, restricting the flow to the pump. When I went looking, I found the old impeller blade in the pipe on the INPUT side of the SALT-water pump - that is, between the raw water strainer and the pump. You might check that first. The broken-off blade was doing exactly what you described - restricting the flow at higher RPMs under load - in this case, the flow TO the SALT-water pump.

You might also check to ensure that your belts are tight to specs. If they are not, they have a tendency to slip at cruise and WOT. Since the FRESH-water circulation pump is belt-driven, the result will be diminished circulation of coolant within the engine and the consequent alarm activation.

Hope I've helped. Been there. Bill - Dulcie

See my response below.

[dorydaze@comcast.net]

Before you spend any money on replacing items you should take a moment and check a few things and report your findings back to the board. Then the other more knowledgable folks then I, can offer more direct guidance.

1 - Check to see that you have raw water being discharged out exhaust

2 - Determine the amount of water is appropriate. If you have a partially torn impeller then you may get some water movement, but not sufficient to cool.

3 - CAREFULLY - use your hand to check the temperature of the discharged water to see if the temperature gauge reading appears accurate.

4 - If the raw water is remains cool and is moving OK then your problem may be a clogged heat exchanger or something worse on the coolant side of the system.....I am assuming you have already checked your coolant level.

Just trying to gather as much information as possible to help narrow down the problem without sending you in 12 different directions.

I have turned it over to a mechanic; It appears when the rpm's are turned up the anti freeze is pushed out through the radiator cap. Yes there is raw water coming out the exhaust pipe. He has checked the heat exchanger, impellers, seacocks and water pump (everything outside the engine). He is doing a test tomorrow to determine if it's it a cracked head or head gasket
Thanks
Phil

[Chris Reinke]

Phil - Sorry to hear that it was not a simple fix. I am very curious now to know what the cause was so please let us know. Hopefully it will be something simple (read as "not costly") and we can all learn something.

[dorydaze@comcast.net]

Chances are if the water is flowing freely out your exhaust at idle, it is passing freely through the heat-exchanger. I wrestled with overheating of a TMD-40A for six months before I discovered that the previous owner had, at some time in the past, let the impeller deteriorate to the point that a blade tore off and lodged in the cooling water pipe, restricting the flow to the pump. When I went looking, I found the old impeller blade in the pipe on the INPUT side of the SALT-water pump - that is, between the raw water strainer and the pump. You might check that first. The broken-off blade was doing exactly what you described - restricting the flow at higher RPMs under load - in this case, the flow TO the SALT-water pump.

You might also check to ensure that your belts are tight to specs. If they are not, they have a tendency to slip at cruise and WOT. Since the FRESH-water circulation pump is belt-driven, the result will be diminished circulation of coolant within the engine and the consequent alarm activation.

Hope I've helped. Been there. Bill - Dulcie

See my response below.

I have turned it over to a mechanic; It appears when the rpm's are turned up the anti freeze is pushed out through the radiator cap. Yes there is raw water coming out the exhaust pipe. He has checked the heat exchanger, impellers, seacocks and water pump (everything outside the engine). He is doing a test tomorrow to determine if it's it a cracked head or head gasket
Thanks
Phil

[cbrenton]

Have the radiator cap pressure tested. It may be blowing off inappropriately and it's a quick, cheap fix.

Charlie Brenton
"Carol Anne"