Exhaust Water Temperature

Hi,
We have a Volvo TMD41A which doesn't overheat but produces lots of steam and the exhaust water temperature seems excessively high. We changed the exhaust elbow and impeller which didn't make much difference.
Could it be that the heat exchanger is clogged?
Thanks

 

Have you measured the exhaust water temperature?

 

Hi,
Thanks for responding. At 1500 RPM it was at 42 Celsius and at 2000 RPM it was at 51 Celsius.
Thanks

 

That is not too hot. It seems there is no problem.

 

We have not been able to measure the temp when running faster which is when we have the worst problems, we have even been stopped by the coastguard as they though we had an engine problem due to the steam.

 

"Steaming exhaust", ie white smoke is a sure sign of reduced seawater flow in these engines. First check the strainer (including the sealing rings around the pipe connections). There are two versions; strainer on pump suction side or on pressure side. The first is sensitive for air leaking into the pump.

The most probable cause, however, is dirt in the oil cooler, since it comes after the pump, but before the heat exchanger. You will find instructions in the Volvo manuals and spare part Pictures available on the web.

 

Heat exchangers have caps that can be removed for inspection and cleaning. Do you have reasonable access to it?

 

Thanks for the ideas, I will check them all out. The strainer is on the suction side and I have always thought that it should have a O ring in the lid to provide the seal and will look into it more.

 

For approx. 10 EUR you have an infrared thermometer that enables you to read local temperatures and find "hot spots" without touching anything.

 

A lot depends on the exhaust design, and the mixer. You could also look at it another way, the seawater is absorbing all the heat it can.
Do you have a muffler installed, and if so what type.
I have mucked around a bit with my own boat and exhausts, and in tropical Queensland, in summer, at full power, mine will still steam. No part of my exhaust is over 50 degrees celcius, and the sea water side of my engine is very much up to scratch.
In the end, if no part of the internal exhaust components are getting too hot, and there is plenty of flow, and this isn't a problem that has just started ( your boat has always done this) I wouldn't be worried.

 

Any sea water on the boat should never get above about 140F as that is when the salt will start to come out and leave deposits.

 

Hi, I work for a company called vestas aircoil who design and manufacture charge air coolers for large diesel engines. Any problems with your heat exchanger maybe i can advise

 

ucti
Many strainers come with cork gaskets that don't last long, especially if the covers are overtightened. I found that the gasket on mine is the same size as the rubber gasket on a plastic 55gal drum, and lasts forever.