My BMC 1.5 runs cool

[SimonA]

I have a BMC 1.5 diesel engine on my boat, it was rebuilt about 2 years ago and ever since it runs cool. Even after about an hour of running time the temperature gauge has only come up slightly and the water in my Calorifier is still cold. The temperature will eventually come up to normal after a few hours.

Could it be the thermostat is stuck open?

 

[Sans Bateau]

Could it be the thermostat is stuck open?

Almost definitely.

 

[dhippey]

Yep, I concur.

Regards,
David H.

 

[VicS]

Take thermostat out and renew it if its obviously stuck open.

If not check the temperature at which it opens by putting in pan of hottish water and then heating slowly through its correct operating temperature ... you'll need a thermometer or a thermocouple on a digital multimeter


The temperature at which it should just start to open should be marked on it, maybe also the temperature at which it is fully open.

Check with your manual that you have the correct thermostat fitted. Those for salt water cooled engines open at a much lower temperature than those for fresh water cooled engines.

 

[greenalien]

Given that you've had the problem ever since the rebuild, perhaps the thermostat was omitted altogether!

 

[Jim@sea]

This engine was fitted in a lot of JCB's and it was common practice to remove the therostat completely.

 

[dash300]

This engine was fitted in a lot of JCB's and it was common practice to remove the therostat completely.

Really? Sounds a bit small for a JCB!

 

[SimonA]

Given that you've had the problem ever since the rebuild, perhaps the thermostat was omitted altogether!

Ummm. I wonder. I will have a look next time I'm at the boat.