8kw westerbeake generator losing water

[motion30]

Ok. . s o I ?have a westerbeke 8kw diesel generator. Recently it overheated. problem a dead water pump impeller .after replacing the impeller retrieving all the loose parts I Ran it. and it Promptly overheated again. no fresh water in the reservoir. Okay so I fIlled it. Ran Perfect for over 2 hours. next time I started it overheated again, no water in the reservoir. so I pressure test the system and seemed to have a leak in the heat exchanger. Pulled that off took it to the radiator shop They find no leak. there is no water in the oil and no apparent external water leak. So where is the fresh Cooling water going

[Hudson Force]

Give me a little help for myself or others like me that are sometimes slow to see all the possibilities.

You're losing water/coolant in the fresh water coolant reservoir that should be a closed system. In addition, you are having repeated failure of the raw water impeller in the open raw water system.

Are you continuing to have a strong raw water effluent when you start to generator with a good impeller?

I wonder if you are vaporizing your coolant with overheating from the lack of raw water flow or overheating with the loss of the coolant first.

I'm wondering if our impeller in the raw water system is not holding prime and therefore, losing your water with the next restart. Of course the answer about the raw water effluent with running is most important.

[motion30]

Hudson
Yes losing the fresh water. Impeller failed once. Good flow of water out the exhaust. Strange thing is it will run for hours with water temp at 180. After shut down is when the fresh cooling water is lost. Was hoping heat exchanger was the problem.

[Seeking Solace]

I had a similar problem with a coolant loss that turned out to be a bad gasket on the fill cap. It would run fine and at normal operating temperatures. After shutdown the temp would climb enough to overcome the gasket on the cap and water would weep out as steam. It also had an overflow that was eventually found to have a crack in the reservoir that was slowly leaking down.

If coolant is not being lost because of a leak in the heat exchanger and there is no obvious leak while running, wait for a few minutes after it has gotten to temp and then look for leaks. Pressures will rise after shutdown that may cause leaks that wouldn't otherwise be noticeable. It was not until after this pressure rise that leaks became apparent and only after careful observation. You may also consider putting a dye into the coolant that will show up under a UV light. Doing that final leak test with the dye will show you exactly where the coolant is going when it escapes the system. Even if it is steam it will show up on nearby surfaces under the light.

Good luck with finding your leak. It took me a long time and a lot of patience to find my own, but as soon as I got it fixed another one cropped up. When that happened it was back to square one until I found it again. Don't discount going back and checking something that you may have already checked. If you're failing a pressure check there is a leak somewhere. You can have a headgasket leak into the cylinder that is discharging into the exhaust without contaminating the oil. Do a compression test on each cylinder that is timed and it may reveal if that condition exists. Also look for pressure that is getting into the cooling system from compression. Steam is a powerful cleaner. If you're operating at 180F you are not far from the 210F required to boil water. Depending on what type of coolant you're using the boiling point may be higher. Looking for signs of steam cleaning around pumps and fittings may give you insight into a possible leak as well.

[Kenomac]

Are you loosing coolage into the bilge pan below the genset? We have a 10kw Westerbeke and have gone through similar/same issues. Have you checked all the hoses? Might seem obvious, but some are difficult to access and sometimes the leak can only be detected when coolant appears in the drip pan.

Your shut off sensors should be shutting down the genset long before extended overheating can take place. Are your sensors OK and haven't been bypassed?

If you're not loosing coolant via the heat exchanger, there's only two other places it can be going. Into the bilge or out a leaky head gasket (if it's the same as a car engine?). But in that case you'd be seeing steam billowing out your exhaust.

[motion30]

[. QUOTE=Kenomac;2246787]Are you loosing coolage into the bilge pan below the genset? We have a 10kw Westerbeke and have gone through similar/same issues. Have you checked all the hoses? Might seem obvious, but some are difficult to access and sometimes the leak can only be detected when coolant appears in the drip pan.

Your shut off sensors should be shutting down the genset long before extended overheating can take place. Are your sensors OK and haven't been bypassed?

If you're not loosing coolant via the heat exchanger, there's only two other places it can be going. Into the bilge or out a leaky head gasket (if it's the same as a car engine?). But in that case you'd be seeing steam billowing out your exhaust.[/QUOTE]

Yes all the sensors are intact and working. I can find no water in the drip pan. And yes the water pump side of the unit is up against a bulkhead. Will have to do a more thorough check for external water leaks the confusing part is when I test it with a radiator pressure tester I was getting air bubbles from the sea water hose to the exhaust riser. Is it possible that the heat exchanger would not leak when it's cold they are for the radiator repair outfit cannot find the leak?

[zeehag]

have you checked the cap for water?? try that.
if it is a pressurized cap, you will have found your answer.
they do wear out.
and your heat exchanger--- they fail and water leaves your system as if someone stole it.

[zeehag]

cap
heat exchanger
check color of your oil. you DID overheat the engine......

[motion30]

Originally Posted by zeehag

cap
heat exchanger
check color of your oil. you DID overheat the engine......

Yes i did install a new 15lb cap. I am still not convinced the heatexchanger does not leak. A new one cost $450.

[motion30]

Zee. Oil looks good. I thought i looked at all the basic things but i am missing something for sure. The odd thing is once i refill the cooling system if will run for hours no problem. But once i shut it off. The water dissappears

[Kenomac]

I think you have an undetected leak from a hose.

[Seeking Solace]

The UV dye will leave no room for doubt. UV dye can be found in any automotive store.

[DeepFrz]

originally posted by motion30:
Will have to do a more thorough check for external water leaks the confusing part is when I test it with a radiator pressure tester I was getting air bubbles from the sea water hose to the exhaust riser. Is it possible that the heat exchanger would not leak when it's cold they are for the radiator repair outfit cannot find the leak?

Believe what you experience, not what someone else has told you. If you are getting air bubbles in the sea water hose you have a leak. Wishing it weren't so wont make the leak go away. Maybe if you dismantle the heat exchanger you will find the problem.

[jamhass]

Have you run the pressure test again? If so what did you find?

I had a slow coolant leak on my main engine. Could not find it. Pressure test was fine.

Turned out to be the primary coolant pump. A worn seal that only leaked when the engine was running and the coolant got warm. Finally found it by very close inspection looking for rust/corrosion marks.

Good luck

[zeehag]

Originally Posted by DeepFrz

Believe what you experience, not what someone else has told you. If you are getting air bubbles in the sea water hose you have a leak. Wishing it weren't so wont make the leak go away. Maybe if you dismantle the heat exchanger you will find the problem.

oh yeah donot forget to wipe down your machine and tranny when you stop its run. then wait. with the someone mentioned dye-- look after engine cool. check bilge for concentration of color. you will find the sneaky leaky. i used green antifreeze to find my coolant leaks. was easy.


as for affording a new for such platinum pricing.. if there is a boiler plant in your area--take in old one--they will create a beauty out of the old one and it will work nicely . buy a spare also. will be cheaper made than shipped. btdt.
my last one was rebuilt for 20 usd here in mexico.
in san diego --150 usd at frasier boiler in nasty err national city, san diego.