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

[EthanC]

Hi Roger, thank you for your reflexion. It is possible is the thermostat that stop the coolant to rise up and down in the expansion tank? Ethan

[seabreez]

Originally Posted by EthanC

Hi Roger, thank you for your reflexion. It is possible is the thermostat that stop the coolant to rise up and down in the expansion tank? Ethan

NO… The thermostat is only there to prevent the coolant from travelling to the intercooler until the engine temperature warms up the coolant sufficient enough to reach the pre-determined (stamped on the thermostat) opening temperature. At that time hot coolant will pass through the thermostat opening until the cooler coolant cools the thermostat and closes the flow. And the cycles repeats itself.

The rise and fall of the coolant in the surge tank (expansion tank) is only relative to expansion and contraction of coolant in the system cause by heat. The surge tank has a cold level. When filled at that level, observe it when hot. The level will be a little higher. When the engine cools the level that contracts should return to the level when cold. It is very important to solve this asap. Here is why… If the level does not change, this indicates the level in the engine goes down because of a leak and this leak causes the coolant level to lower all the time and be replaced by AIR. Air does not cool an engine. Remove your cooler cap (in automotive terms… radiator cap) check the level COLD NOT UNDER PRESSURE. The coolant level will be low… fill to the top and reinstall the cap. Run the genset and warm it up good, you should see the level in the surge tank rise a little. The next day, do your observations. Did the level go up or down in the surge tank and did it go down under the cap? If the level in the tank does not change, you have a leak. Check under the cap… if the level is down a little you have a leak. If the level is down under the cap… this means that there is air in the system.

The expansion of the coolant and then rad cap that opened and let the hot coolant in the engine expand and go to the surge tank. The air and coolant enters the surge tank by the bottom… allowing air to rise above the coolant. When the engine cools and the coolant contracts, this will allow the coolant from the surge tank to return to the engine by the negative or suction back to the engine, And this cycle repeats itself until all air is removed and replaced by coolant… ask me more… Roger

[skipperpete]

Hi EthanC
I have more questions than answers and the first is .... have you solved the expansion tank problem yet? If not here are a few things to consider.
Did you re install the thermostat when you fitted the new circulating pump? If not then the engine might simply be running cold with not enough expansion to reach the 12-14 psi required to pop the cap and leak into the tank.
I have to ask......is the short rubber tube on the expansion tank lid to the bottom of the tank still in place?
I’m interested to know how anode crumble could block the heat exchanger in such a way that required it to be replaced, did the core collapse and allow seawater and coolant to mix? This could have a lot to do with the expansion tank behavior.
I am baffled by the presence of a water leak from a new circulating pump and I doubt that hi belt tension could do it..... I have seen high amp Balmar alternators on this 3TNE yanmar and no pump leaks at all.
So finally, is the engine getting hot and is the top tank losing coolant. Did you run it with the pressure cap off to observe for bubbles.
I,m interested to know what you find but suggest that a lot of engines don’t even have expansion tanks and run with an airgap in the top tank.... Beta is one. Cummins is another.

[EthanC]

Hi Pete, thank you for your detailed message, I will make the check up you suggest and I will comeback to you.. Regards, Ethan

[Cadence]

Someone correct me if I'm wrong. Re: coolant-water expanding and contracting. I though it only expanded when it froze?

[EthanC]

Hi Pete, sorry for the delay I try to find what’s going on with not much success.

The expansion thank is not resolve and still not moving up and down as is supposed to be.

I keep off the radiator cap for 15 minutes at the very beginning and I see some bubbles (like a coca cola in a glass) and after it was just pumping out some coolant like boiling water on the stove. At one point I see some air bubbling out but not too much.

The expansion thank is OK, rubber tube etc.,

Per hour of running the Gen: I have one drop or 2 of coolant from the weep hole of the fresh water pump. Seems stable.

The heat exchanger is brand new of 3 months and had a regular zinc replacement 2 times, one per month.

So finally, it’s working anyway so what do you think will happen in the future if I leave it like that?

Thank you for answer, I really appreciated your precious help, from you and everyone in this forum.


Ethan

[skipperpete]

Thanks for bringing us up to date with your investigations. If I was the engineer, I,d go all over it with a laser heat gun and log the actual temperature at the senders, thermostat housing, the coolant top tank and the heat exchanger ( both the in and the out temps) then write em down in the engine log. Also make sure the shutdown circuit is operating on all sensors just in case the engine overheats ( that circulating pump leak is still a worry even though stable). As I mentioned previously, a lot of engines never had expansion tanks at all, just a hose from the filler cap flange to the bilge and an airgap in the top tank to allow for expansion.

[EthanC]

Thank you Pete... The idea of a temperature gun it's a good idea!!! Thanks!



I will still running it untill I found a good mechanic. Hope for the best meanwhile...


Best regards,






Ethan

[foggysail]

If you see bubbles in the coolant you may have a blown head gasket. Also check your oil. Sometimes with a failed head gasket the coolant finds its way into the lubrication oil.