Kohler Generator Coolant Expansion Tank Level WON'T Rise! Please Help.

[EthanC]

Hi, I am desperate, I have a Kohler 9EOZ generator and in the expansion tank (the little bottle on the side) the coolant level doesn’t rise or get lower as normal. Instead the fresh water pump leak from the hole on the side of the pump. I replace the pump and again the pump leak from the hole and the overflow bottle level don’t move. Thank you in advance to anyone who can give me a troubleshooting about this issue. Regards, Ethan

[slug]

Originally Posted by EthanC

Hi, I am desperate, I have a Kohler 9EOZ generator and in the expansion tank (the little bottle on the side) the coolant level doesn’t rise or get lower as normal. Instead the fresh water pump leak from the hole on the side of the pump. I replace the pump and again the pump leak from the hole and the overflow bottle level don’t move. Thank you in advance to anyone who can give me a troubleshooting about this issue. Regards, Ethan

Perhaps the radiator cap is kaput , your system is over pressure

Coolant can’t escape to the expansion tank

[EthanC]

I thought about it and I replace the radiator cap for a brand new one.... Problem stay.. Thank you.. Any other suggestion?

[EthanC]

I tough about it and I replace the radiator cap for a brand new one.... Problem stay.. Thank you.. Any other suggestion?

[billknny]

Originally Posted by EthanC

I tough about it and I replace the radiator cap for a brand new one.... Problem stay.. Thank you.. Any other suggestion?

I know this is simple and obvious, but have you checked that the hose is not clogged?

If coolant is free to flow down the hose, there are two possible problems.

One, the cap is the wrong type. It needs to be the kind with two sealing surfaces. One for high pressure, and one for low.

If have a leak that is bad enough, the fresh water system can never generate enough pressure to open the high pressure relief and push coolant UP into the tank. It also might not be able to generate vacuum LOW enough to suck coolant IN past the cap.

[EthanC]

Hi Billknny, Thank you for your concern... Really appreciated...


The radiator Cap is the right part number going with the generator and is new of today, that's it's OK.



When I open the Cap I hear a "Shussss" so there are pressure. Also the tube between the tank and the overflow bottle is clear (I blow into it with a straw...).


The heat exchanger is brand new (2 months).


The fresh watre pump is brand new (last week), the last pump was leaking a lot: 1 drop per second, the new one is 1 drop per hour (for the oment)!!!.


I don't undertsand why the coolant in the overflow bottle dont go up and down as is suppose to be and I think this is the fresh water pump problem.?


Thank you again and best regards, Ethan

[skipperpete]

If a new coolant circulation pump is leaking already, you have more to think about other than the expansion tank. Have you been chasing the cause of an overheat for a while already? Why a new heat exchanger?
If the prime mover is a yanmar and has the two tiny auto vent pipes on the coolant pump,check to see if they are blocked.
If the engine is a Lombardini and has had a previous overheat then the head gasket might be blown, are you getting bubbling in the top tank?

[EthanC]

<div> Thank you... I change the heat exchanger because a broken zinc was to create an obstruction. The generator is a Kohler 9EOZ with a Yanmar engine. On the pump there is a hole in the side and that where the coolant leak. I don’t see the 2 tiny vent pipes. I have no bubbles in the Expansion tank, the coolant level always still the same.

Again, thank you I really appreciate your thoughts. Ethan


<span style="font-family:&quot;Times New Roman&quot;,serif; mso-fareast-font-family:&quot;Times New Roman&quot;;mso-ansi-language:EN-US;mso-fareast-language: FR-CA" lang="EN-US">

[svHyLyte]

Is the coolant expansion tank vented? If not, back pressure might block flow into the tank.

FWIW...

[EthanC]

Originally Posted by slug

Perhaps the radiator cap is kaput , your system is over pressure

Coolant can’t escape to the expansion tank

Yes the cap of the bottle expansion look working normally... I open comopletly the bottle, coolant still not move...


Can't be the thermostat ?


Thank you!!! Ethan

[Cadence]

Ethan, the thermostat may be it or maybe your not running the engine hard enough to require the overflow but that would not explain the water pump. Is possible you have an obstruction within the engine water passages. Has a water pump impeller failed?

[01kiwijohn]

Originally Posted by EthanC

Yes the cap of the bottle expansion look working normally... I open comopletly the bottle, coolant still not move...


Can't be the thermostat ?


Thank you!!! Ethan

Ethan, I am curious. You mention a leak at the engine coolant pump. There is a weep hole, that's true, but it can only mean one thing. That the pump seal is leaking. Assuming there is not excessive system pressure, something is causing that seal to leak. It should not drip at all.
A common situation I see is that the alternator belt is way too tight, causing the bearings in the pump to be overloaded, subsequently causing those seals to leak. It a a "face type" seal and will not tolerate much run-out. I'd loosen the belt, get a pressure tester and pressurize the system to about 10% above its' specified amount, then look around for the source.

[a64pilot]

Is the heat exchanger completely full, to the top? If there is any airspace then it will act as a spring and the coolant won’t flow back and forth between the expansion tank, the air will compress instead.
Liquid isn’t compressible of course and because of this the pressure will rapidly rise and overcome the pressure setting of the cap, add even a little air and the air will compress, keeping pressures below the relief setting of the cap.

Even if the heat exchanger is completely full. I bet you still have some air trapped on the system from where you changed the pump out, sometimes it’s hard to bleed all the air out.
I’d recommend you running it for a while with the cap off and see if the water level in the heat exchanger drops, don’t worry about a little overflow, it may even “burp” and push quite a bit of water out, and then the level drop a lot, this can happen as a big air bubble finally makes its way out.

Doesn’t explain your water pump leak though, long term your going to need to fix that, and it may also be the problem, it may be leaking out enough to keep pressure from building and overcoming the pressure setting of the cap, and after shut down it may be letting air in too, so that no coolant is sucked in from the overflow tank.

[EthanC]

Yes the heat exchanger is full.... The water pump is new of last week. The first hour the belt was too tight and I loose it after, maybe too late!!! I will try the open cap whising for a burb... Big thank you for your support and concern, your great! Ethan

[seabreez]

Originally Posted by EthanC

Hi, I am desperate, I have a Kohler 9EOZ generator and in the expansion tank (the little bottle on the side) the coolant level doesn’t rise or get lower as normal. Instead the fresh water pump leak from the hole on the side of the pump. I replace the pump and again the pump leak from the hole and the overflow bottle level don’t move. Thank you in advance to anyone who can give me a troubleshooting about this issue. Regards, Ethan

On that generator you have two systems. The first one is the fresh water intake from the outside or sea water going through the intercooler. The second system is the closed system. This is usually filled with glycol for rust prevention and this is the system that uses the expansion tank. If the coolant does not rise and fall you have a leakage in this coolant system. To check this you must pressurize this using a pressure pump typical to automotive use. (radiator pressure test). This will pressurize the glycol coolant side. Do this test cold as the glycol is more prone to leak when it is cold. Difficult to see and detect. Sometimes you need to place a paper under the engine to try and detect the leak. Check all hose connections and if you see dried white or coolant colored powder near the connections, I would check there very closely for leaks.

You mention that the water pump leaks. You have to make sure which pump is leaking. Is it the fresh water pump or the circulating coolant pump. If it is the coolant circulating pump... that is your problem. Why your tank does not work is simple. When expansion occurs when HOT, the coolant leaks out through there or other places and not expanding and going in the surge tank. And when the engine cools down and shrinks or contract, the coolant is replaced by air coming in where the leak occurred.

A coolant recirculation pump has a 1/4 inch hole under the pump. That hole is in the space between the seal and the bearing. Very hard to see as the drive pulley hides the hole. This hole is to indicate if the seal is leaking. If there was no hole and the seal would leak, the coolant would migrate to the bearing and destroy it. You can ask me more if you wish... Roger