Engine overheating problem ... help

[lewisa]

This sounds very much like you have air in the system. This is a common problem with Perkins and Westerbeke engines. If you top off the coolant, run the engine for 5-10 minutes, and then see if you need to add more coolant. If you do, it's probably an air issue. If you take off the heat exchanger cap, you can often watch the coolant in the heat exchanger get sucked down shortly after stopping the engine.

If that happens, repeat the process until you no longer need to add coolant.

If that doesn't work, you may need to bleed the sytem. I do this by removing the hose from the hot water tank exit and run the engine until a steady flow is achieved -- usually pretty quickly.

Good luck.

[Gianluca]

I have also a westerbeke and after 5000 hrs of working fine, I noticed that my coolant was going down slowly and the temperature going up, also slowly. I found that the coolant pump was leaking from whipping hole. I replaced twice since the first replacement had the same issue and solved the problem…
Good luck,

[IanTrail]

I have spent many hours chasing over-heating problems too. My best suggestions (both already mentioned by others) are:
1. Get a cheap infra-red thermometer ($/€/£10). Very useful for seeing what is or isn't flowing and whether the thermostat is open.
2. Try burping the cooling system. I have a 'burping funnel', an ordinary plastic funnel which fits tightly into the filler cap. Run the engine up to temperature (thermostat opens) then try revving and blipping. Any air in the system eventually causes large burp to rise up the funnel and escape. Careful - it's hot.

My cooling system is difficult to fill without air-locks so I'm getting pretty slick at burping it!

[Brise]

It’s a Yanmar, but it may help for bleeding …after 8 min
https://youtu.be/N21eEAOMf4Q

[JimZeigler]

Had a friend with a Catalina 34 fitted with a 3 cylinder Universal. He started having overheating problem and replaced the impellor, every hose and had the heat exchanger cleaned at a radiator shop. Did not solve the problem, until we removed the heat exchanger and placed it in 5-gallon bucket of muriatic acid diluted by 50% after removing both end caps. Amazing amount of colored foam came out of the tubes even though this heat exchanger has supposedly been clean out at the radiator shop. Only take a few minutes of exposure, a thorough rinse and the inside of the tubes were shiny. No more overheating problem. I read later that the heat exchangers on these engines were noted for not having excess colling capacity.

[Shaneesprit]

Originally Posted by edhuckle

Hello all:
So, I have a sailboat with a 40 year old Westerbeke W27a four cylinder diesel. This engine has been incredibly reliable for year and only a few problems. However, right now we have a strange overheating problem. Here is the sequence of events:

*** first and foremost, it cannot be anything with the impeller/sea water cooling system as we have tons of water coming out of the exhaust and this is unchanged ****

1. For the last few weeks the engine was perfect but I noticed I had to keep adding little bits of water to the fresh water reservoir. Figured I had a tiny leak somewhere in piping.
2. We have had squeaky belt issues for a while until I replaced it. When I replaced it the water pump pulley seemed fine.
3. Had a major overheating event, turned engine off and luckily were able to sail to an anchorage. I noticed that water was coming out of the water pump bearings behind the belt pulley. Took off belt and saw that the bearings/seals were shot and the shaft was all wobbly.

At that point I was convinced that the water pump had failed and caused the problems … and that if I replaced it then we would be good as new. Miraculously, I have a spare fresh water pump that I pillaged off an abandoned W27 engine I found at a boatyard. It is rusty but the shaft and bearings spin perfectly fine and to me it seems fine.

4. Put on backup fresh water pump, started it up and still overheating. The overheating is strange as the temperature (as measured by the water temp sender near the thermostat) rises from 100 to 140 or so, then rises VERY quickly through 150 to 220, then alarm goes off.
5. Next, I removed the thermostat, thinking maybe this is the problem. Same issue
6. Next I removed several hoses and was able to blow air through the entire engine cooling water loop, both forward and backward (I think). So it doesn’t seem there is a clog in the fresh water system …

Here are some observations:
Water goes in a loop from where the input pressure cap is (in side A front end of the exhaust manifold) then down a pipe that wraps around the engine, then into the fresh water pump, then into the engine cavity, then up to the thermostat housing where the temp sender and alarm sensors are, then a pipe back to side B front end of the exhaust manifold, then out of side B rear end of the manifold, into heat exchanger, out of heat exchanger and back into side A rear end of the exhaust manifold … which completes the loop.

When I start the engine up and have the pressure cap off the fresh water rises a bit, and bubbles out and floods out the cap. I assume that this is just trapped air bubbles finding their way through the system?

When I opened up the thermostat housing it “almost” “seemed” that it was dry? Could this part just not get water and dry out?

Another time it seemed that we ere overheating, but the water located at the pressure cap (which was off) was hardly even hot??? Also, one end of the fresh water heat exchanger input was much hotter that the output side - this is expected if the heat exchanger is doing it’s job but it seemed extreme.

finally, one time shortly after overheating, I carefully took off pressure cap and a bunch of water squirted out as if it were under also of pressure ... didn't get burned and it didn't even seem that hot???

So, can anyone tell me that next steps? One thing I hate about this is that, for sea water you can see it coming out of the exhaust so you ACTUALLY KNOW that it is flowing through the system. But the fresh water loop is a closed look and it is hard/impossible to tell if it is flowing around in a loop, or is stagnant.

Also, good/bad … I am stuck on Staniel Cay in the Exuma Islands (Bahamas) … so although this is paradise, it is very hard to get parts or even internet at times.
Thank you soooo much in advance,
Ed

Hi sounds to me like classic head gasket.
However you are not in a good place for repair of an engine and don’t know what you will find if someone looks at it.

I have a suggestion to try, search for K seal
Order at least 2 bottles but only use one.
I put this in a car I didn’t want to repair, drove it for well it was 7 or 8 years ago, the new owner tells me it’s still going strong.
Link below.

Never take the cap off when it’s hot unless you like visiting hospitals - coolant can boil over due to the change in pressure.

https://www.kseal.com/uk?gclid=Cj0KCQiA95aRBhCsARIsAC2xvfxcD-Sw5q1gDHlg0iYR8FF8SBpKSzL4AdYUkDOD69K_35Eemj5RJ74a Avh6EALw_wcB

[darren_bowls]

Originally Posted by svfinlandia

That is my guess also. Just because water is going through the heat exchanger does not mean that it is exchanging head with the antifreeze. Although the fact that your antifreeze does not seem hot does not support this supposition, I would remove and boil out the heat exchanger anyway. If it hasn’t been done in several years it no doubt needs it.

Al, S/V Finlandia

I just went through a similar issue with my low-hour but older Yanmar. I was getting plenty of water out of the exhaust, but when we disassembled the heat exchanger, it was 35% blocked. I removed the thermostat during troubleshooting, but after the heat exchanger fix, the temp gauge didn't even register at idle as it did before. I reinstalled a new thermostat later.

I also agree with other posters about elevated water heaters (like mine). A valve at the high point in the system is a good idea for burping air. Unfortunately, air gets trapped in the hoses and doesn't circulate. I found that out when I installed my WH and got no hot water. I was able to burp my cooling system by running the motor without the pressure cap on after a bunch of fussing around. Eventually, the air cleared out and I got circulation.

The head gasket could be leaking now if your engine got too hot and shut itself off. My engine shut itself off because my overheating buzzer failed. And it's impossible to always be watching the temp gauge, especially when at sea and it's at ankle level. Fortunately, my head gasket was OK (this time), but overheating my car diesel recently ruined the head gasket. Make sure your warning buzzers are always working!

Steam at the thermostat sensor from low coolant levels will cause temp gauges to spike, but that's not always an indicator of core engine temps that ruin your engine, thank god. But I panic anyways. Hehe...

The spiking temps make me think you have trapped air. From experience, a leaky head gasket drips water out of the system and only requires topping off the cooling tank, a cup at a time, every now and again.

Hope you are able to work through the issues and get back on the water stress free.

Fair winds

[stormalong]

Originally Posted by edhuckle

yes, I had an airllock and i burped it alot and it totally fixed the problem. thanks, Ed

For those of you that continue posting the OP has already replied that the problem has been fixed.

[Icarus]

Originally Posted by edhuckle

Hello all:
So, I have a sailboat with a 40 year old Westerbeke W27a four cylinder diesel. This engine has been incredibly reliable for year and only a few problems. However, right now we have a strange overheating problem. Here is the sequence of events:

*** first and foremost, it cannot be anything with the impeller/sea water cooling system as we have tons of water coming out of the exhaust and this is unchanged ****

1. For the last few weeks the engine was perfect but I noticed I had to keep adding little bits of water to the fresh water reservoir. Figured I had a tiny leak somewhere in piping.
2. We have had squeaky belt issues for a while until I replaced it. When I replaced it the water pump pulley seemed fine.
3. Had a major overheating event, turned engine off and luckily were able to sail to an anchorage. I noticed that water was coming out of the water pump bearings behind the belt pulley. Took off belt and saw that the bearings/seals were shot and the shaft was all wobbly.

At that point I was convinced that the water pump had failed and caused the problems … and that if I replaced it then we would be good as new. Miraculously, I have a spare fresh water pump that I pillaged off an abandoned W27 engine I found at a boatyard. It is rusty but the shaft and bearings spin perfectly fine and to me it seems fine.

4. Put on backup fresh water pump, started it up and still overheating. The overheating is strange as the temperature (as measured by the water temp sender near the thermostat) rises from 100 to 140 or so, then rises VERY quickly through 150 to 220, then alarm goes off.
5. Next, I removed the thermostat, thinking maybe this is the problem. Same issue
6. Next I removed several hoses and was able to blow air through the entire engine cooling water loop, both forward and backward (I think). So it doesn’t seem there is a clog in the fresh water system …

Here are some observations:
Water goes in a loop from where the input pressure cap is (in side A front end of the exhaust manifold) then down a pipe that wraps around the engine, then into the fresh water pump, then into the engine cavity, then up to the thermostat housing where the temp sender and alarm sensors are, then a pipe back to side B front end of the exhaust manifold, then out of side B rear end of the manifold, into heat exchanger, out of heat exchanger and back into side A rear end of the exhaust manifold … which completes the loop.

When I start the engine up and have the pressure cap off the fresh water rises a bit, and bubbles out and floods out the cap. I assume that this is just trapped air bubbles finding their way through the system?

When I opened up the thermostat housing it “almost” “seemed” that it was dry? Could this part just not get water and dry out?

Another time it seemed that we ere overheating, but the water located at the pressure cap (which was off) was hardly even hot??? Also, one end of the fresh water heat exchanger input was much hotter that the output side - this is expected if the heat exchanger is doing it’s job but it seemed extreme.

finally, one time shortly after overheating, I carefully took off pressure cap and a bunch of water squirted out as if it were under also of pressure ... didn't get burned and it didn't even seem that hot???

So, can anyone tell me that next steps? One thing I hate about this is that, for sea water you can see it coming out of the exhaust so you ACTUALLY KNOW that it is flowing through the system. But the fresh water loop is a closed look and it is hard/impossible to tell if it is flowing around in a loop, or is stagnant.

Also, good/bad … I am stuck on Staniel Cay in the Exuma Islands (Bahamas) … so although this is paradise, it is very hard to get parts or even internet at times.
Thank you soooo much in advance,
Ed

Some time ago I had the same problem, coolant loss via the pressure cap overflow into the bilge and temp shooting up to 200C° ( normal.y 170°)
Cleaned the heat exchanger..no win
Found a small leak at the heat exchanger end cap..fixed..no win
Thermostat ok
Installed a coolant overflow bottle..started to fill up and sucked coolant back in when engine was cooling, had to add coolant a couple of times..now settled in and no more flacctuations of c level.
For some reason there was an airlock and the coolant was not circulating

Check engine oil if contaminated with coolant..clear or milky.
Check if the coolant is not escaping into the exhaust via a leaky gasket at the exhaust manifold.
Otherwise check circulation at the header tank if possible.
Airlock

[OneBoatman]

I agree with those saying you have an air lock in the fresh water loop. This usually occurs in the run to your hot water tank. Check to see that these hoses are not kinked, that they are no longer than needed and that have proper connections. If there is a small leak in these runs the difference in height between your heat exchanger and the hot water tank connections are will allow it become air bound after sitting. This will prevent circulation of your coolant the next time you start your engine. I have also seen engines that overheat due to carbon build up in the exhaust elbow grossly restricting but not fully blocking the sea water flow, but it seems pretty clear from you description your issue is on the freshwater side.

[Uncle Bob]

Originally Posted by stormalong

For those of you that continue posting the OP has already replied that the problem has been fixed.

Literacy and comprehension can be overrated at times.