Westerbeke 4107 Operating Temp ?

[Uncle Buck]

What is the ideal operating range, and at what temp is she running too hot?

Thanks

[s/v Beth]

Mine is 35 years old, but well maintained and stays at 180 F all day long....

[hellosailor]

Salt water cooled? Or fresh water?

With fresh water or a closed loop cooling system, you want to run at 170F-190F depending on the manufacturer's spec. The hotter it can run, the better it will run, in general. But if there's raw salt water going into the engine, you need to run no higher than 140-145F because at that point, salt crystals precipitate out of the salt water and block the cooling passages.

These days, you can pick up a cheap IR non-contact thermometer to doublecheck that parts of the engine block really aren't overheating, without blindly believing the thermostat rating, too.

[s/v Beth]

That thermometer trick is a good one, I think it would work with cars too.

[shakey doug]

Hi,
The 4107 is a wet liner engine and as such does not take kindly to running over 190f for extented periods, the normal runnning range is 180-185f. 4107s running on salt water would be long gone.

Shakey.

[scallywag]

My Westerbeke 30 is running cold. I replaced the impeller in the salt water cooling pump. I have an infared gun that shows the diesel is running at 130 degrees. I ran the diesel without a load. Should I try to replace the thermostat? What would happen if I didn't replace the thermostat? The thermostat housing has a bolt and an allen wrench type bolt.

[hellosailor]

130F isn't all bad for a salt water cooled engine. Remember that the salts crystalize out around 140F and inside your engine, it WILL be marginally hotter than the readings you are getting on the outside.

If you are not sure, pull the thermostat and put it in a pot of water on the stove, along with a kitchen thermometer. By 140F it should be wide open. Thermostats sometimes fail, even brand new ones are sometimes DOA, so that's the first thing to check.

Most marine thermostats are set up with a "bypass loop" which is different from the on/off way they are used in cars. If you remove the thermostat, typically all the water goes through the engine INSTEAD of the bypass loop, and you wind up with an engine that runs very very cold. If your thermostat housing has 3 water passages running in/out of it--that's normal, one is intake from the impeller, one goes into the engine, the other is just the bypass dump. With that setup you pretty much MUST have a thermostat installed.

[scallywag]

Hellosailor,
Thanks for your respnse. I failed to mention, the engine is fresh water cooled with a heat exchanger. I really do not want to pull the thermostat. It ran about 175 degrees, when I first purchased the s/v. When the closed water cooling system pump went bad, the engine shut itself down because of being to hot. After the pump was replaced the temperature guage only registered a maximum of 170 degrees. I thought it registered that amount because of the guage being pegged to maximum. Since the hose to the hot water heat sprung a leak, I have had this problem not getting up to 175 degrees. I bought the infared gun to double check the temperature gauge. So I am pretty sure the engine is not operating at the correct temperature.

[hellosailor]

Ah, a heat exchanger. Then 170-190F is "correct" depending on what your engine maker calls for. 130F on the block would probably be too cold, it is hard to guess which parts of the block should be just how hot but I'd start in the same place: Pull the thermostat, bring it to a boil on the stove and see if it is working correctly. Even if the impeller was somehow "too powerful" the thermostat should have the final word. And despite the prices chandleries charge for them--thermostats are incredibly simple cheap machines.

[scallywag]

Hellosailor,
Thanks again. I really do not like engines but I do not want to damage it. I will try to find a thermostat. We have a local Westerbeke dealer, being Memorial Day Weekend, I do not want to make the trip to the shop.

[hellosailor]

Running too cold for a short time (a weekend of occassional use, etc.) wouldn't damage the engine, it would just run poorly and waste fuel. I know what you mean about holiday weekends and trips for parts, I feel the same way.

By the way--do check that the thermostat isn't installed backwards, that's actually possible on some engines. there should be a "flow" arrow or something similar stamped on the thermostat, it should point away from the incoming water. Sometimes that, or a wrong gasket, is all the problem comes down to.

[scallywag]

Hellosailor,

Thanks for the tip.

John

[perchance]

Thermostat ribbon test. Insert a ribbon under the thermostat valve and suspend the thermostat in hot water with a thermometer and note the temp at which the thermostat drops off the ribbon. this will give you the opening temp. If it opens too soon the engine will run cold.