Engine overheating problem ... help

[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 cooling water">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

[Cheechako]

I had a problem like that once when I had reassembled the engine. I previously had the head worked on .
What was going on was the thermostat was surrounded by air and thus heat wouldn't transfer to it and it stayed shut. I solved it by filling the engine with hot boiling water, closing the thermostat housing quickly and starting the engine.

However you say you took the T stat out, so that's not it.
I was going to suggest a bad freshwater pump, but you changed that also.

So sea water is flowing through readily. That means something is not circulating the fresh water in the engine.
Do you have a transmission cooler the engine water goes through? Maybe that is clogged.
Are you sure the used fresh water pump was good? (impellor not spinning on the shaft or...?)

[tkeithlu]

I think that Cheechako has it right in the last part of his post. It sounds like your coolant is not circulating. It's boiling in one place and sitting cool in another. The "usual suspect"is that coolant pump. Try opening a hose on the pressure side of the pump and see if you get a whopping shower. If you do, then a blockage is still a candidate. If you don't, it's time to look at that pump, starting with it's drive from the engine, its linkage to the shaft, the connection of the impeller to the shaft, the condition of the impeller, the presense of the cam that compresses the impeller on one side, anything.

Good luck with it.

[roryboy]

Check the heat exchanger(s) . If it is half blocked, you will still get alot of water through it. It just goes very fast through that half. But it does not remove enough heat. Look for simple before you tear things apart.

[Jackg]

I had a W27. This sounds like air in the coolant. It needs to be "burped." As I recall it was a royal pain to do, and, alas, I don't remember the process. The way the hoses are routed makes it easy for a big air bubble to get trapped in the system.

[stormalong]

Originally Posted by Jackg

I had a W27. This sounds like air in the coolant. It needs to be "burped." As I recall it was a royal pain to do, and, alas, I don't remember the process. The way the hoses are routed makes it easy for a big air bubble to get trapped in the system.

I also had a W27, a long time ago. Do you have a water heater piped to it? That makes it especially difficult to bleed off the air. I added a fitting from an engine flushing kit at the high point of the plumbing. It is just a straight coupler with a cap on it.

Left it open while adding coolant to the idling engine until it started to come out of the cap.

[jim King]

If you're at Staniel, have "Chubby" take a look at it. He's a mechanic at Staniel and is quite the genious with motors. You can go to the kiosk at the main dock and ask for him. He got me going in a few minutes and wouldn't take anything for his time. I of coursed gave him a big bonus for his time and expertise.
jim

[Engine man]

Do you have a separate water heater tank plumbed to the engine? [ for hot pressure fresh water use] We have seen many incorrectly installed water heater tanks that cause engine overheating due to air locked in the system. If your tank is at the same level, or higher than the engine, you need a remote header tank installed, to capture & purge air from your engine FW cooling system. This purging action is continuous when the engine is running.
A coolant recovery bottle should also be installed.

Other suggestions - Buy or rent a cooling system pressure tester. This will allow manual pressurization of the FW cooling system and pressure cap, to check for leaks. You should be running 50/50 mix of antifreeze and water. Combine these 2 liquids BEFORE pouring them into the engine, as they will not mix correctly if poured in separately.

When was the last time the heat exchanger was serviced? You can first shut the raw water intake c-cock, drain the FW coolant, and remove the heat ex from the engine. Now remove both end caps from the Heat EX and soak it in vinegar [ mild acid] overnight. Flush with a fresh water pressure hose, then look through the Heat Ex tubes. All should be clear. Use something softer than copper [ wood or plastic dowel ] to clean any plugged tubes.

It's also possible that your "major overheat" damaged the head gasket. Now on the compression stroke of the piston, compression is bypassing the gasket and entering the FW cooling passages in the head or block. This may explain the air / bubbles seen below the pressure cap.

NAPA sells a kit for testing this possibility. Joe

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

[LouK]

I've had this problem, burping is in order......

[clakiep]

Would not be good news, but what if there is some leakage of the cylinderhead gasket, putting bubbles and creating vaporlocks in the cooling system ?

Capt. Claus - ocean tramp of the eighties

[jmschmidt]

Can't help since you use the words "fresh water." Please differentiate between "coolant liquid" (anti-freeze freshwater mix) and raw water (from an ocean, river or lake).

[Sailshabby]

Keep us posted. Interesting problem.

[svfinlandia]

Originally Posted by roryboy

Check the heat exchanger(s) . If it is half blocked, you will still get alot of water through it. It just goes very fast through that half. But it does not remove enough heat. Look for simple before you tear things apart.

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

[Halam]

Sounds like head gasket to me, as suggested by Engine Man Joe. Look for 'head gasket test kit' on google. Mind you, when I thought that was the problem on my car it was just a worn-out pressure cap.
Halam

[donradcliffe]

All good advice, but unfortunately the NAPA block check kit is probably not available where you are. Do you have, or can you borrow an infrared temperature gun?

I would first rule out the coolant air lock and the fresh water pump. Leave the thermostat off for now. It appears that the coolant is not circulating.

Always remember to NOT add cold fresh water to a hot engine, as you will damage the block/head/head gasket. If you want to save some time, heat the added water on the stove first.