Removing the Thermostat

[limmer]

Is there any major reason why you should not remove the fresh water thermostat and have the engine run at a lower temp if you are in warm climates. I see the reason for them in the cooler climates. Will this hurt a diesel engine if it is operating at the lower temp? cheers limmer

[tackdriver]

The thermostat is there for a very good reason. Engines don't like running cooler than they were designed. The oil doesn't reach the right viscosity and the combustion process is less efficient. You'll wear out the engine faster, and use more fuel.
My knowledge is based more on gasoline engines, but I can't see why this would be much different in diesels. Diesels are to some degree self lubricating because the fuel is oily, but I still don't think I'd recommend pulling out the thermostat.
cheers
James

[Maine Sail]

Originally Posted by limmer

Is there any major reason why you should not remove the fresh water thermostat and have the engine run at a lower temp if you are in warm climates. I see the reason for them in the cooler climates. Will this hurt a diesel engine if it is operating at the lower temp? cheers limmer

If you regularly sail in 140-180 degree water you should be fine.. Most diesels are designed for a specific operating temp range and removing a stat, even in "warm" water, won't even get you close to design spec temp range..

[Chief Engineer]

It amazes me that people even think this stuff up.....what would be your motivation to do this?

[Ex-Calif]

Actually it is possible that removing the thermostat will make the engine run hotter.

The transfer of heat in the exchanger requires a certain dwell time. Removing the restriction of the thermostat can circulate the water faster resulting in reduced heat transfer.

Run it the way they designed it and you'll be fine.

[limmer]

chief eng. I'm just trying to keep you busy by wasting your time with stupid questions. but i should have explained, I am about to head south and was going thru spare parts and one of the thousand things that came up was the thermostat and knowing these things tend to break or not work after time I wasn't sure if or how long I could run the engine without one until a new one was available. Yes i agree with all of you that the engine was designed with one so it should have one. but yes a major reason to me is more fuel with poor combustion and wear on the engine. cheers

[Strygaldwir]

If I recall correctly, the thermostat's were originally put in place to help get the engine to operating temperatures faster, not keep it warmer. Combustion generates a LOT of heat, even in very cold temperatures, you're going to get to operating temperatures. This is especially true in diesels that rely on VERY high pressure and temperatures.

So, as suggested, you can rip out the valve assembly inside the thermostat and be okay. But, when you got back to very cold temperatures, you'd want to see about replacing it to minimize the rough, not as efficient, warm-up time.

[hugosalt]

"If you sail in 140-180 degree water you should be fine"

Maine Sail, I regularly sail in water 140-180 degrees, it's usually when
the Admirals on board!

[mike d.]

hugosalt here's to that!!!!! what will happen is that the oil will not come up to temp and increase fuel usage the cylinders will not come up to temp, because the oil being sprayed into the skirts will be cold (relatively). also combustion will suffer because the fuel will not atomize properly in cool cylinders, the engine will probably soot up more than normal, and the engine will not heat up more because of unabated water flow. the raw water pumps are designed to push x amount of water, depending on the engine so it will still only move so fast thru the system and cool the whole engine down, but because there is no stat (a metering device) controlling temp the motor cools because of to much flow. remember a thermostat has a thermo-regulator, in that it changes the amount of flow as temps change. this can be from heat generated by engine or changes in external water temp, so flow fluctuates with these variables