Westerbeke W50 potentially overheating

[a64pilot]

Originally Posted by jimbunyard

210 F is well within the operating range of petroleum based oils, synthetics can go much higher before having problems.

Petroleum oils' high end operating temperature should not exceed 250 F or thereabouts.

Any oil needs to get up to around the boiling temperature of water to properly get rid of water and prevent the formation of acids.

As noted above, the t'stat starts to open at it's rated temperature (+/- 3F) and continues to open for about 15-20 degrees before reaching fully open.

This is correct, you need oil to get to a min of 180f to cook off the moisture, many boats don’t get there, but it would be better if they did.
Many boats oil is overcooled by being cooled with raw water.
The oil cooler on a Diesel engine that is cooled by radiator coolant, (almost all over the road Diesels for example) is as much of an oil heater as it is a cooler, to ensure the oil gets to operating temp. And stays there.

Average high performance automobiles oil is cooled by radiator coolant at 195F and just average highway speed oil temp is around 220F.

This is an aircraft engine, but oil is pretty much oil.
https://generalaviationnews.com/2011...l-temperature/

[a64pilot]

This for automobiles
https://www.hotrod.com/articles/engine-oil-temperature/

[felizcortez]

We had a mechanic look at the engine this morning to get a second opinion. The diagnosis was confirmed to be a bad gauge or sender. They had a second IR gun which were pretty close to my original measurements. The engine is running in the 180 to 185 range depending on load. The mechanics comment was that our engine is running perfectly. He wasn't concerned about the fresh water cooling of the oil cooler.

They had a spare gauge and I alligator clipped it to the sending unit and it matched the temperature on the IR gun right about 180 to 185 depending on load. They said that is expected based on the thermostat opening and closing. The old gauge reads about 15 to 20 degrees hotter than what the newer gauge shows. The sending unit is okay based on this test. The gauge just needs to be replaced. I'm going to see if I can buy the spare gauge they had or I will order one. I attached a pic of the new gauge running under load and the old gauge was 15+ degrees hotter.

Appreciate everyone's help on this problem. I also learned a lot about my cooling system which will help significantly.

[capeharj]

You changed and checked a lot of stuff, but, how about the most obvious, thermostat.

[nknowland]

Get an infrared thermometer to verify engine temp. Don’t trust the gauge!

[Triumph]

Two things. One, yes, you will get the 180 temp on the thermostat housing even if engine temp is 200+. Remove the thermostat and see what the gauge reads. This is a simple check that you should have done after checking the water intakes, etc.
Two; If it isn't the thermostat, I'd be a couple of beers it's you exhaust elbow. If it's older than say 6 years, it could be getting corroded and closed up. That would would cause high temps at higher RPMs. You've got to take it off and check. Remove the entire exhaust section from the engine and get the manifold in a vise. Stick a 4 foot strong pipe down it's opening and use it for leverage to turn the stuck threads to get it off. Make sure of the thread direction first.

On the "probably cause scale", these two items are high on the list and not that hard to tackle.

Bill on TRIUMPH

[felizcortez]

Originally Posted by nknowland

Get an infrared thermometer to verify engine temp. Don’t trust the gauge!

We used an IR thermometer to check this. I also hooked up a separate gauge to the sender and it confirmed our old one is showing 20 degrees above what it should.

[felizcortez]

Originally Posted by Triumph

Two things. One, yes, you will get the 180 temp on the thermostat housing even if engine temp is 200+. Remove the thermostat and see what the gauge reads. This is a simple check that you should have done after checking the water intakes, etc.
Two; If it isn't the thermostat, I'd be a couple of beers it's you exhaust elbow. If it's older than say 6 years, it could be getting corroded and closed up. That would would cause high temps at higher RPMs. You've got to take it off and check. Remove the entire exhaust section from the engine and get the manifold in a vise. Stick a 4 foot strong pipe down it's opening and use it for leverage to turn the stuck threads to get it off. Make sure of the thread direction first.

On the "probably cause scale", these two items are high on the list and not that hard to tackle.

Bill on TRIUMPH
The Book of Sail – Cruising gadgets, knowledge, and ideas for the cruising sailor

We verified that the gauge was incorrect with a separate gauge. Hooked up a spare gauge and the engine read what it was supposed to. 180. I also had this verified with a local mechanic.

I took the exhaust tubing out and looked up into the elbow, it wasn't clogged.

[Joe Okros]

When last did you clean your prop?

[Nicholson58]

Originally Posted by felizcortez

When I disassembled the hoses and had the end cap of the heat exchanger off I was able to look at input and output connections. They were both clean.

Do you still think it is potentially not the sender even though the gauge reads 200 and the IR thermometer says about 180 on the thermostat housing? Will measure the resistance today on the sender.

Our Westerbeke ran hot. Did everything you noted. I placed the 180 thermostat in a sauce pan with all spares. The installed thermostat did not open until 200. Go figure.

[captchetco]

We have the original Perkins 4-108 from 1976. Totally rebuilt in 2004, cruised heavily since 1996. Spent 15 years in MX and CA. The Perkins and Westerbeke 50, cool well on sloppy maintenance north of San Francisco. The further south you go, the warmer they run, until about south of Tehuantepec, they can no longer be run hard or even normally without over temps. Our remedies are 180deg thermostat. Clean coolant heat exchanger regularly (annually or more); remove it from engine, "boil out" with muratic acid, push a soft bronze rod thru all tubes, This alone will keep us at about 210deg at cruise; with a 15# pressure cap, all is good, including occasional 220d.

A better result from using "Diesel Coolant. It eliminates the bubbles that form on the coolant side of cylinder walls, and passes heat better. Good for about 5-7 deg improvement.
The final and best change has been to add another heat exchanger, (raw water to trans oil) in the transmission oil line that goes to the engine oil cooler. Push RW through it with a deck wash pump. It dropped the trans tempurature to 140-150, and the engine to about 190deg, and no overheat on hard running.
The Perkings and Westerbeke manuals do not tell you that the Velvet Drive transmission should run at 140 deg, which is only doable if the oil/trans HX is on the raw water ahead of the engine coolant HX, and none I have ever seen are plumbed that way.

In summary, the Perkins is overheat tolerant, if you are running a high pressure cap, and of course good hoses. Central America overheating is common. You can reduce the heat by eliminating the transmission heat from the engine oil cooler, which takes a raw water heat exchanger and a deck wash type raw water pump. It also helps to use new tech diesel coolant.

Other things relevant are Injector pump timing; engine room temp; keep engine and trans clean; increase the raw water pickup to 3/4", from original 1/2"; realize that a high output alternator working at limits puts out a great amount of heat (maybe add another solar panal to reduce alts load?) Eliminate tight bends in the exhaust, and the RW system.

[Joe Okros]

Why the 180 degree thermostat? Perkins stipulates the 75 degree celsius/167 F thermostat for marine application,----that may be your problem right there.

[felizcortez]

Originally Posted by Joe Okros

Why the 180 degree thermostat? Perkins stipulates the 75 degree celsius/167 F thermostat for marine application,----that may be your problem right there.

The engine is based on a BMC1.8L. The thermostat is supposed to be 180. It says it in the manual as well.

We cleaned our prop this month and I was hauled out for bottom paint in February and have had the bottom cleaned each month along with the prop since then.

s

[Joe Okros]

OK,-but Perkins 4.108 also stipulates 180 in the manual for most uses like the taxis, tractors etc they are normally used in. However they do specify the cooler thermostat for MARINE use. Does the BMC differentiate between Marine and other use? If not I would try the cooler one because most of these manuals are not written for Marine use as most of these motors intended use is not Marine. Perkins obviously discovered that it made a difference hence specifying a colder thermostat for marine use. YMMV.