Westerbeke W50 potentially overheating

[felizcortez]

My temperatures have been climbing up according to my gauge in the cockpit to about 200 degrees.

We are cruising in Mexico currently and are currently in La Paz. Before we go further into the Sea of Cortez, I want to fully understand what hte issue is.

Things I have done so far.
1. I replaced the fresh water pump in Turtle Bay on the way down - the old one had play in the pulley - it wasn't leaking yet, but I didn't want to mess with it.
2. I replaced the raw water impeller in the pump because the old one was about 2 years old. The old one looked fine and I still get good flow through the system and out the exhaust.
3. I unhooked all the hoses in the raw water system and looked for blockages/pieces of impeller etc. Nothing obvious was found. While I had this apart I replaced the Zinc in the heat exchanger.
4. I ran barnacle buster through the heat exchanger and the overall system. This cleaned out the heat exchanger pretty well and I have a before and after shot for your reference.
5. I bled the fresh water coolant at the petcock that is on the thermostat until coolant came out of the bleed point.


A few things I have found.

1. The oil cooler is shown plumbed into the raw water circuit in the engine diagrams, but mine is plumbed into the freshwater system on the exit of the heat exchanger. I'm not sure whether this is a problem as it has been like this for years while I lived in San Diego. I did see in the manual where it says that the oil cooler can be plumbed into the fresh or raw water system, I just thought it was strange since the other members of the tartan forum have their oil cooler plumbed into the raw water circuit. From the oil cooler in my system the coolant goes to the hot water heater then returns to the engine.

This is the section I found in the owners manual. However, the diagram in the manual shows different - See picture below.
9. ENGINE LUBE OIL COOLER:
Lubricating oil carries heat away from the engine bearings and other friction surfaces. The oil circulates from the
lube oil pump, through the engine, through the engine oil cooler, and back to the oil pump. The oil cooler may be cooled either by engine fresh water or by sea water.

See below video for coolant routing.
https://youtu.be/asGEEyLi4T8

When running the engine under load the system seems to run in the 200 degree range according to the gauge (see attached picture). I run the blower and it seems to back down a bit. I shot the thermostat housing with an infrared thermometer and it is reading at about 180 which is where the thermostat is supposed to open, so I'm not sure whether I have an actual overheating issue or not.

I am trying to find specifications on the temperature sending gauge so I can test it to see whether it is correct or not? Any insight on how to test this component? I've never done it before.

Any other thoughts on what to do to diagnose/debug?

Pics are below of the heat exchanger before cleaning, the exhaust elbow sea water input. Diagram of the cooling system.

Will do another post with pics of the heat exchanger after runnign barnacle buster.

[felizcortez]

Attached are pictures of the heat exchanger after using Barnacle buster last night for a few hours. I hooked up the flush in forward and then reversed the flow to run through the system backwards as well. As you can see it cleaned out quite a bit of the build up.

I also installed a new zinc after flushing.

Any help with regards to what to try next would be appreciated.

[sailah]

First find out which engine block the W50 is based on and then find factory service manual so you can get resistance specs for the sensor.

Second I'd test your sensor

https://www.youtube.com/watch?time_c...&v=ZX3lbi9yGuE

Do you have an overflow tank? When the engine is hot, like 200F, do you see any bubbles in this expansion tank?

I have a Westerbeke 44B. Originally I had a hot running engine from day I bought the boat. Found the RW inlet to heat exchanger (you and I have same heat exchanger) was necked down from the 7/8" hose ID to probably only 25% open. It was bad. That cleared up any warm running and I was back to 180 rock solid. It sounds like you likely took care of that with BB treatment. BUt do check the inlet from RW pump to HX, that's where mine was bad, my tubes looked great. And it was salt that precipitated out I think. Grey. clay-like, scraped right out.

However it appears that engine was overheated at some point as I had a bad head gasket and head was warped a few thou. The symptoms for this on my boat were running hot to the point of overheat, coolant getting pushed out of exhaust manifold and up into expansion tank. Had to pull head and get it cut, new gasket.

Feels like low water thruput in your case tho.

[sailah]

Also did you remove HX and gently rod out the tubes? Hard to tell from the pic how clean they are. Just running BB won't clear up a really fouled tube. I use a piece of aluminum TIG wire and round over the end. I shove this thru so I know I get flow. Then run the solution.

[felizcortez]

Originally Posted by sailah

First find out which engine block the W50 is based on and then find factory service manual so you can get resistance specs for the sensor.

Second I'd test your sensor

https://www.youtube.com/watch?time_c...&v=ZX3lbi9yGuE

Do you have an overflow tank? When the engine is hot, like 200F, do you see any bubbles in this expansion tank?

I have a Westerbeke 44B. Originally I had a hot running engine from day I bought the boat. Found the RW inlet to heat exchanger (you and I have same heat exchanger) was necked down from the 7/8" hose ID to probably only 25% open. It was bad. That cleared up any warm running and I was back to 180 rock solid. It sounds like you likely took care of that with BB treatment. BUt do check the inlet from RW pump to HX, that's where mine was bad, my tubes looked great. And it was salt that precipitated out I think. Grey. clay-like, scraped right out.

However it appears that engine was overheated at some point as I had a bad head gasket and head was warped a few thou. The symptoms for this on my boat were running hot to the point of overheat, coolant getting pushed out of exhaust manifold and up into expansion tank. Had to pull head and get it cut, new gasket.

Feels like low water thruput in your case tho.

The overflow tank is in the manifold. It is supposed to be filled to about 1 inch below the pressure cap. If it boils over you will get water/antifreeze going out of an overflow tube. That hasn't happened yet. I did overfill it when I changed the water pump and the excess coolant flowed out of that overflow upon starting the engine.

I checked all the hoses and didn't find any blockages. I also had the freshwater pump off 3 weeks ago and changed the impeller.

I feel like I am getting good throughput of water.

I did a rudimentary test of the gauge today. When it is disconnected from the sender it reads zero and when it is connected to ground it pegs at full scale.

I have the technical manual for the engine but it doesn't call out the resistance specifications on the sender. I blew a fan on it with a multimeter hooked up and I saw the resistance change, but I don't know what are correct values.

With regards to rodding the heat exchanger I did put a pick into the tubes but it was only about 6 inches long so it wouldn't have gone completely through.

Removing the heat exchanger requires removing the entire exhaust manifold so I was trying to do this in place.

I tried to remove the exhaust elbow today as well but couldn't get it off the exhaust manifold. I removed the hose and used a screwdriver to try to clean it out. It didn't seem very clogged either.

[GordMay]

Originally Posted by sailah

First find out which engine block the W50 is based on and then find factory service manual so you can get resistance specs for the sensor.
Second I'd test your sensor
https://www.youtube.com/watch?time_c...&v=ZX3lbi9yGuE

I doubt he has a gauge/sender problem.
However ...
Temperature Gauges:
Measure Resistance from Tan Sender Wire (disconnected from Gauge) to Ground.
American Temp. Senders will read: 450 Ohms (Engine Cold @ 100 deg F)
or 29.6 Ohms (Engine Hot @ 250 deg F )
European Temp. Senders will read: 281 Ohms (Cold @ 40 deg C) and 22 Ohms (Hot @ 120 deg C)
More ➥ http://www.cruisersforum.com/forums/...sting-645.html

➥ Testing Engine Gauges (2) - See also Wiring Diagram & Testing Instructions Cruisers & Sailing Photo Gallery

➥ Testing Engine Gauges - See also Wiring Diagram & Sender Resistances Cruisers & Sailing Photo Gallery

[sailah]

I agree doesn't feel like a sensor or gauge but those are simple enough to rule out.

I personally would suspect the HX but that's based on my own Westerbeke experience. Removing my HX isn't easy but it's pretty straight forward. Removing exhaust manifold is more complicated and means you need a new gasket, I don't need to remove mine.

In my case, the tubes were actually fine and pretty clean. I would never have seen the salt necking down the inlet unless I removed it.

I'd totally remove HX and clean off the boat, then you can eliminate it from the problem spots.

[sailah]

Here's what mine looked like after having a 200F running Westerbeke. I also noticed the PO was not much on keeping things tidy and a drip was totally corroding everything. I have since replaced all of the hoses and I don't leak a drop. Painted engine.

This scraped out easily. Came back, although not as bad, after 2 years. So now it's on my maint list every 2 years to pull HX and ensure it's all spotless. Was probably blocking 75% of the area. Still looked like I was getting good water out the stern which is why I didn't suspect a flow issue but it was.

[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.

[felizcortez]

i measured the resistance of the sender this morning with the engine cold and it was 750 ohms at 77F

[stormalong]

FYI The Westerbeke 50 is a Perkins 4-108. I knew a cruiser with one and his manual was identical to mine but with a different cover.

IMO you should do another iteration of tubestack cleaning.

The best way to do this is remove it from the engine, Put it into an appropriate sized PVC pipe that is capped on one end and fill it with white vinegar. Let it soak overnight and then flush with fresh water. If it did any good you will see a lot of stuff wash out.

[sailcrazy]

Following. I have an Onan 6/5kva, with a Kuboto 3-cyl diesel engine. This season it has started to overheat on me, especially when I load it up. It should run OK with a 29amp load or less, but earlier this season we loaded it up to 21amps...and she shut down (overheat). Once it cooled down it started/ran fine-and we've kept her going with lower loads only. It's Ok with a 12-14amp load and a short -term load up to 18-19 amps. We're into the marina and up on the hard in a couple of weeks...plan to replace all the cooling hoses (all original, now 29 yrs old!) and remove/clean the heat exchanger. If I could find a radiator shop I'd have it boiled and rodded.

[Sailor647]

We had the same issue when we left the cold water of the Pacific Northwest and headed into the warmer waters of Mexico. We have a W46 and think we have the problem resolved. So far, so good.

In addition to regular maintenance (impeller check, thru-hull/strainer cleaning, heat exchanger cleaning with acid), we:

Increased the size of the air intake by removing the pathetic box muffler and installing a proper air filter.

Moved the exhaust from under the boat (underwater) to the stern. This was creating a lot of back pressure and was not letting the engine breathe.

Added an oil cooler.

From the raw water pump, plumb the oil cooler, transmission cooler, then the heat exchanger.

If you want to come check out what we did, let us know. We're also in La Paz right now.

[Sailor647]

Originally Posted by felizcortez

While I had this apart I replaced the Zinc in the heat exchanger.

We removed our zinc from the heat exchanger permanently. All they do is plug them up! We found no advantage to having that additional zinc, since we have others connected to the engine.

[Sailor647]

Originally Posted by felizcortez

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.

After the engine is hot, shoot the temp on the oil pan and compare it to your gauge. Also shoot the hose before and after the oil cooler. Then compare it to your raw water hose. There's a good chance the fresh water coming in is already to hot to cool the oil significantly.