Kohler 5kw LOC Error

[CaptainEd]

EDIT: Model number is Model is 8-E32OZD

This generator will be the death of me.

So I started it to warm it up for a simple oil change. After about 90 seconds it quit with the LOC code on the display. Did some research, looks like the most common cause is low water flow, even though it can look fine coming out of the side of the boat (it did look fine).

Checked the coolant level, it fine.

So next I tackled the seacock/thru-hull. Well, indeed it was restricted by something, which I was eventually able to clear. Hooked everything back up, started it, notice even better water flow, and it quit again, same error.

Next, the impeller. I found one blade missing and upon pulling it, found the blade in the outlet port of the pump. Great! It didn't get sent to the heat exchanger! Put everything back together, started it, terrific water flow, and it quit again.

I'm going to pull the cap off the heat exchanger next but i doubt I'll find anything. In the meantime I thought I would tap the collective for any other ideas.

Also, if anyone knows how to bypass the sensor for this I would appreciate the knowledge. I don't know that I'm going to be able to find a replacement in stock to continue the trip.

Running without it isn't an option in this Miami heatwave. I have to have a charging source as well since the alternator seems to have taken a crap too.

Thanks,
-Ed G.

Thanks,
-Ed G.

 

[High Wire]

90 seconds of running won’t cause a valid overheat. Could be the coolant temperature switch or exhaust temperature switch. Does your manual have a wiring diagram? If so it should show both and how to bypass. It would help if you could post a picture of the diagram showing those two switches.
Oil level ok?
Is there a v-belt that drives the engine coolant pump or is it gear driven?

 

[STB]

Hey Ed,

Extremely unlikely the sensor is bad. I'm not sure what unit you have, but some of those small kohlers have relatively smaller exchangers and need a lot of water flow. This is especially true when the water is warm as it is in your neck of the woods now.

Pump out or drain as much coolant as you can and then pull both rubber end caps off the exchanger. Then you'll know the story. It may have more debris, or scaling. Or both.

I don't think your model has a turbo, but some of those that do have an exhaust temp or TMAP sensor also.

But, I really think you want to fix the cooling, not disable the sensor. It's saved you twice already, right?

It is possible it was damaged by the overheat, but I sure wouldn't run the unit without it. I'd first check the temp with an IR gun to confirm that it was bad and then not run the genset until I'd installed a replacement.

Remember, without that sensor you'd have been shopping for a while new genset right now.
I don't know which genset you have. I can be more specific with a model number.

But, attached are a couple of pictures that might help orient you.

LOC is almost always a problem with the waterflow, but it isn't caused by a waterflow sensor -- it is cause by a temperature switch. The engine is actually over temperature.

 

[STB]

90 seconds of cooling might not cause a valid overheat with a conventional switch, but if the controller sees heating up too fast it shuts down.

Many of these the controller uses a temperature from a sender to decide vs a conventional over temp switch, so they can flag on heating up too fast vs just too hot.

I've never seen one of these smaller units with a flow sensor. They always have engine temp sensors. And some, seemingly more so with turbos, have an exhaust temperature sensor (or TMAP sensor).

I really think the only things that can trigger this error on a smaller units are the temp sensor and the exhaust temperature or TMAP (exhaust temp and manifold pressure) sensor if it has one. The exhaust sensor may flag a problem faster than the water sensor.

I'd know more with a genset or controller model number.

I really wouldn't disable a safety sensor. Especially when it just seemingly saved my bacon twice.

Remember...for your engine you have gauges. I have them for.my genset, too. But, I'll bet you don't just 'cuz they are rare. So, unlike your engine, you can't easily keep an eye on this.

BTW, my Kohler has a J1939 interface. I added terminating resistors and the Yacht Devices engine gateway. So, my MFDs and some smaller instruments can show my genset data coming from those sensors via the controller. I love being able to monitor it. And that gateway was WAY cheaper than Kohker's kit.

 

[MYTraveler]

Your sensor may be looking for low flow, not high temp. And certainly you can't have overheat temps in 90 seconds. I would find the flow sensor and test it.

 

[CaptainEd]

90 seconds of running won’t cause a valid overheat. Could be the coolant temperature switch or exhaust temperature switch. Does your manual have a wiring diagram? If so it should show both and how to bypass. It would help if you could post a picture of the diagram showing those two switches.
Oil level ok?
Is there a v-belt that drives the engine coolant pump or is it gear driven?

I just pulled the manual out and will look for the schematic. Oil level is OK. The pump is belt driven. Tension seems fine. It's pumping a lot of water, no squealing.

I'll get a photo of the diagram if I can't figure it out from that myself.

Thanks,
-Ed G.

 

[STB]

I don't know this model to look, but on all of the small kohlers that immediately come to mind, everything is gear driven except possibly the alternator if there is one.

 

[STB]

I just pulled the manual out and will look for the schematic. Oil level is OK. The pump is belt driven. Tension seems fine. It's pumping a lot of water, no squealing.

I'll get a photo of the diagram if I can't figure it out from that myself.

Thanks,
-Ed G.

Hey Ed,

What model of genset is it?

Thanks!

 

[CaptainEd]

90 seconds of cooling might not cause a valid overheat with a conventional switch, but if the controller sees heating up too fast it shuts down.

Many of these the controller uses a temperature from a sender to decide vs a conventional over temp switch, so they can flag on heating up too fast vs just too hot.

I've never seen one of these smaller units with a flow sensor. They always have engine temp sensors. And some, seemingly more so with turbos, have an exhaust temperature sensor (or TMAP sensor).

I really think the only things that can trigger this error on a smaller units are the temp sensor and the exhaust temperature or TMAP (exhaust temp and manifold pressure) sensor if it has one. The exhaust sensor may flag a problem faster than the water sensor.

I'd know more with a genset or controller model number.

I really wouldn't disable a safety sensor. Especially when it just seemingly saved my bacon twice.

Remember...for your engine you have gauges. I have them for.my genset, too. But, I'll bet you don't just 'cuz they are rare. So, unlike your engine, you can't easily keep an eye on this.

BTW, my Kohler has a J1939 interface. I added terminating resistors and the Yacht Devices engine gateway. So, my MFDs and some smaller instruments can show my genset data coming from those sensors via the controller. I love being able to monitor it. And that gateway was WAY cheaper than Kohker's kit.

There is actually a separate code for engine overtemp. I believe this is a flow sensor in the heat exchanger. The troubleshooting for the code is to check the impeller and water flow. My last two boats (both Hatts) had gauges for the genset, but this Mainship does not.

I'll have to check into whether or not it has a CAN bus interface. Our current electronics doesn't have one, but the planned upgrade will.

 

[STB]

This is a 5k Kohker vs a 15k Kohler with a flow sensor? Interesting. What model is it? Thanks!

 

[CaptainEd]

This is a 5k Kohker vs a 15k Kohler with a flow sensor? Interesting. What model is it? Thanks!

Model is 8-E32OZD

 

[CaptainEd]

Hey Ed,

What model of genset is it?

Thanks!

Model is 8-E32OZD

 

[STB]

Since you wrote that it is a 5kw Kohler with a flow awi4xh, I don't doubt you. Just curious to see which one has it and if itnis in newer lines and whatnot.

But, just as an unlikely just-in-case, one wants to look up the genset model and manual, not the controller model and manual. The controllers are used across many gensets and are configured for a particular model. They might support features, and applicable error codes, for one genset model that another genset model in which they are used doesn't have.

 

[STB]

Okay. That's an 8kw genset. I haven't had my hands in one of those recently. I'll try to look it up later.

I'd be surprised if it had a flow switch, but that is just intuition not knowing or specs or having seen.

But, again, if you see it....you know!

 

[CaptainEd]

Hey Ed,

Extremely unlikely the sensor is bad. I'm not sure what unit you have, but some of those small kohlers have relatively smaller exchangers and need a lot of water flow. This is especially true when the water is warm as it is in your neck of the woods now.

Pump out or drain as much coolant as you can and then pull both rubber end caps off the exchanger. Then you'll know the story. It may have more debris, or scaling. Or both.

I don't think your model has a turbo, but some of those that do have an exhaust temp or TMAP sensor also.

But, I really think you want to fix the cooling, not disable the sensor. It's saved you twice already, right?

It is possible it was damaged by the overheat, but I sure wouldn't run the unit without it. I'd first check the temp with an IR gun to confirm that it was bad and then not run the genset until I'd installed a replacement.

Remember, without that sensor you'd have been shopping for a while new genset right now.
I don't know which genset you have. I can be more specific with a model number.

But, attached are a couple of pictures that might help orient you.

LOC is almost always a problem with the waterflow, but it isn't caused by a waterflow sensor -- it is cause by a temperature switch. The engine is actually over temperature.

The generator never overheated. It won't run long enough to even get hot. The last time it was used, it was shut down normally, not by a sensor.

I did pull one of the endcaps and there was one blade of an impeller there. I tried again with the same result once it was removed. The heat exchanger looks amazingly good inside.

It's probably worth noting that this is a fairly new heat exchanger. Probably has just a couple of hundred hours on it. I posted a thread in '21 about trying to get coolant back in the thing after changing the heat exchanger out. What an adventure that was.

 

[CaptainEd]

Okay. That's an 8kw genset. I haven't had my hands in one of those recently. I'll try to look it up later.

I'd be surprised if it had a flow switch, but that is just intuition not knowing or specs or having seen.

But, again, if you see it....you know!

Yea, I noticed that 8kw spec once I dug in. Not sure where I got 5KW from. I'll blame the admiral for that one.

I had to step away from this to try to find an alternator for the main engine but I'll be digging into the manual here shortly.

 

[High Wire]

I just pulled the manual out and will look for the schematic. Oil level is OK. The pump is belt driven. Tension seems fine. It's pumping a lot of water, no squealing.

I'll get a photo of the diagram if I can't figure it out from that myself.

Thanks,
-Ed G.

Ok trying to be clear, there are two separate cooling circuits on your generator. 1- the raw water (seawater) circuit which you said is flowing lots of water out the exhaust. The flow path is intake, strainer, seawater pump, heat exchanger tube side, (That’s where the rubber impeller vane was found) exhaust riser, muffler and overboard via exhaust outlet.
2- the engine jacket water (antifreeze) circuit internal to the engine. It has its own coolant circulation pump built into the engine block. It is usually difficult to determine flow. Sometimes you can see some flow by looking in the pressure cap opening.

 

[BDofMSP]

I had this same problem a couple weeks ago, also on a Kohler 8K but must be older because there is no display for error codes.

The cause in my case was a BROKEN (as in physically broken) exhaust temp sensor. It was broken from chafing against the fragile ceramic part. I was able to get it glued together to get by, and I'm installing the new one this weekend. So the sensor may not have "gone bad" but still could be the culprit.

BD

 

[CaptainEd]

Ok trying to be clear, there are two separate cooling circuits on your generator. 1- the raw water (seawater) circuit which you said is flowing lots of water out the exhaust. The flow path is intake, strainer, seawater pump, heat exchanger tube side, (That’s where the rubber impeller vane was found) exhaust riser, muffler and overboard via exhaust outlet.
2- the engine jacket water (antifreeze) circuit internal to the engine. It has its own coolant circulation pump built into the engine block. It is usually difficult to determine flow. Sometimes you can see some flow by looking in the pressure cap opening.

OK, I'm aware of the two circuits, but didn't think about flow in closed side being an issue. That'd be a first for me.

I do have it narrowed down now. I disconnected the pressure sensor on the heat exchanger and it runs without the error. I found one locally and the Admiral is on a parts run. I'll update the thread if that cures it.

 

[STB]

I doubt a failed pressure sensor a LOT LOT LOT less than I doubted a failed temperature sensor. Those pressure sensors don't seem to get along with the saltwater loop, even though that's their job. They fail on a lot of folks.

Sorry for the false alarm saying that it didn't have one...the confusion over the model through me ad the 5k units don't.

 

[CaptainEd]

I doubt a failed pressure sensor a LOT LOT LOT less than I doubted a failed temperature sensor. Those pressure sensors don't seem to get along with the saltwater loop, even though that's their job. They fail on a lot of folks.

Sorry for the false alarm saying that it didn't have one...the confusion over the model through me ad the 5k units don't.

No worries. I should have dug out the manual and got the proper model number before I posted.

We've got about a 10 hour run tomorrow in triple digit "feels like" temps, with two pampered cats on board. I had to get this sucker going and was a bit panicked.

The switch is on it's way to me. I'll do what I hope is a final update once it's installed.

If there's a part number on that switch, I'll post it as well. I found a lot of similar threads on my journey of discovery but none conclusive.

 

[STB]

I'm impressed you were able to find a part same day. Anytime I try to get a Kohler part it seems to be backordered 6 months!

BTW, I don't want to suggest disabling any safety sensor but, personally, I'm no fan of those flow switches and, well, if the coolant ain't too hot, and the exhaust ain't too hot...

Good luck and enjoy your trip!

 

[twistedtree]

What does this "LOC" code mean?

 

[STB]

On the Kohlers it stands for "LOw Coolant". But it can be a catch all for any tripped sensor relating to temperature or cooling loop flow.

I've seen it show up for tripped flow, coolant temperature, exhaust temperature, and exhaust temperature and pressure (combined) sensors. Sometimes just the sensor. Sometimes real problems including closed seacocks, clogged saltwater loops and coolers, bad impellers, and coolant having leaked out.

 

[twistedtree]

On the Kohlers it stands for "LOw Coolant". But it can be a catch all for any tripped sensor relating to temperature or cooling loop flow.

I've seen it show up for tripped flow, coolant temperature, exhaust temperature, and exhaust temperature and pressure (combined) sensors. Sometimes just the sensor. Sometimes real problems including closed seacocks, clogged saltwater loops and coolers, bad impellers, and coolant having leaked out.

Thanks!

 

[ronobrien]

From what I have read in the thread the error is due to water flow. Is it possible that some of the broken impeller blades wound up at the sensor and obstructing the sensor? Just spitballin'.

 

[Dougcole]

On the Kohlers it stands for "LOw Coolant". But it can be a catch all for any tripped sensor relating to temperature or cooling loop flow.

I've seen it show up for tripped flow, coolant temperature, exhaust temperature, and exhaust temperature and pressure (combined) sensors. Sometimes just the sensor. Sometimes real problems including closed seacocks, clogged saltwater loops and coolers, bad impellers, and coolant having leaked out.

Not that it matters much but I always thought it meant "Loss Of Coolant," which to me means it is not getting cooling water. I have the same genset and that sensor shuts down the motor really quickly when the strainer gets clogged, well before an overheat. My genset intake used to have an issue where it sucked up a TON of grass. It would sometimes shut down the motor every hour in grassy anchorages, so I am quite familiar with the LOC code. I ended up having to install a strainer on the outside of the hull in addition to the big inline groco strainer.



There is another code that comes up when the genset overheats, though I can't remember what it is. I had the raw water pump belt go bad on ours last month (it was a new belt that for some reason stretched so much after install and two subsequent tightenings that it stopped turning the pump) and it threw off a different code than LOC, which surprised me.

 

[STB]

It may be "Loss Of Coolant" vs LOw Coolant". I was going from memory. But, it does function as I described.

Kohler has a bunch of different generators and controllers. Some have flow sensors. Some don't. Mostly it depends upon the size and generation.

Many, including mine, throw LoC for any cooling or temperature related problem as they can't distinguish and cooling problems are most often the source of heat problems.

Those that have both temp and flow sensors distinguish HE for (heat) temp sensors from LoC for flow sensors.At least for those I've seen.

I've attached my Kohler 6EOD operation manual fault code section for reference.

 

[Dougcole]

Thanks for the good info STB. I was not disagreeing with you, just clarifying a little bit from my own experience with the same genset. And yes, HE is the code it threw off when the belt started slipping.