Power Equipment Forum banner

Kohler 20KW standby Generator issues - low oil pressure

2705 Views 49 Replies 11 Participants Last post by  GenKnot
Good day everyone,

I just wanted to share my experience with you all so hopefully it can prevent others from going through this mess.

In January 2018 we decided to purchase a whole home standby generator with automatic transfer switch as we live in an area that does experience frequent outages.

We landed on the Kohler after much debate/research and seeing that the local fire department chose the brand for them, we contacted a local dealer to get it sorted.

Initially, when the team came out to install the unit the generator was placed on the concrete pad and it was fired up for the first run.
It ran for about 30 - 40 seconds before it lifted a ring and completely grenaded the engine. The sound of 3600ish rpms instantly and violently stopping was wild.
Kohler was only willing to replace the engine and not the whole unit however after a lot of pressure from the dealer and myself, a brand new unit was swapped out.

This second unit ran pretty well from 2018-Dec 2021 where it accumulated approx 120hrs of runtime inclusive of the weekly tests plus outages. I began to notice that the interior of the weatherproof housing was coated in a fine mist of oil, this was to the point it was pooling in the bottom of the housing. I contacted the dealer as it was under warranty and had been serviced by them since new. They determined that the intake was full of oil and several oil seals had failed causing it to mist oil absolutely everywhere. This prompted a new engine from Kohler which the dealer installed.

This new engine was installed in March 2022 (supply chain issues I guess), third Kohler engine for us.

On December 15 we experienced a wind storm that knocked power out for 22hrs in which the generator ran flawlessly. I checked the oil after the storm and found not a drop used and the total engine hours were now 40ish hours. The next weekly test of the generator was a surprise for us, the generator threw a low oil pressure light and shut the unit off.

I went out to check it and found the oil filled, looked under the oil cap and noticed a white milky colour to the oil on the cap. I re checked the dipstick and found no water in the oil. The rocker arms all had good clean oil on them and no moisture on them.

I figured it might have been a fluke occurrence so I cleared the code and manually ran the generator. This ran for about 5 min before popping a low oil pressure light and shutting off.

I contacted the dealer who advised that they have had nothing but trouble with Kohlers since they started carrying them in 2018. They did advise that they would come back and replace the oil pressure sensor as they believed it to be faulty (seems odd for less than 50hrs to drop a sensor but maybe). If it didn't work they advised they would push Kohler to replace the whole unit......again.

Again due to issues with parts this has been a good while waiting and we have been forecasted for some bad weather.

Since I had nothing really to lose I tested the oil pressure switch with a multi meter and found with the unit off it would read 2-60 ohms. Given that this is a normally closed switch I cleared the code, rechecked the oil, and manually turned the unit on with the sensor unplugged. While running the oil pressure switch would ohm out to infinity which is a functioning switch. I opened the oil cap and looked in, lots of of good clean oil lubricating the rockers no problem.
I plugged the switch back in and ran the engine for 15min no issue, manually turned it off and rechecked the oil. Again, full of oil and no water.

At this point I'm not sure what is going on nor if the unit will function properly when needed. I hope that this helps someone looking for a standby natural gas air cooled unit to avoid the mess we've had. If money was no option I would pay to swap it for a Generac but I'm stuck with this terrible brand.

Good luck out there and avoid these Kohlers
See less See more
41 - 50 of 50 Posts
Final Update I hope.....

First off I am sorry in the delay in updating everyone on this situation, work has been very busy and I was waiting on Kohler for their response.

So they decided to replace the entire unit and covered the install and removal including the trades people to do their work.

The recommendation from the dealer was to complete the Generac break-in procedure as Kohler did not have one.
So the new unit has been run under load with break in oil for 24hrs and the oil was immediately drained, filter replaced and new synthetic oil filled.

I had the first weekly exercise today which went mostly uneventful. The unit is surging and bucking like it's starving for fuel however I recall one of the previous ones doing that, possibly unit 2 or 3, either way it was fixed with a fireware update. I assume this is the same situation and the dealer will attend to it.

Lastly, Kohler offered a 10yr comprehensive warranty for purchase on this unit which I happily bought. Call it 4 times bitten, 8 times shy or however that saying goes.

I've asked for an update on the cause of the failure but that is in Kohler's hands and we shall see if they provide me with one.

Hopefully this prompts Kohler to produce a break-in procedure of some sort, I read both the install and user manual for the new unit and it has absolutely nothing about this mentioned anywhere in it, very odd.

Thanks again for everyone's input and I'll be sure to let everyone know if the saga continues or finally has come to an end.
See less See more
  • Like
Reactions: 1
Thanks for keeping us informed.

I've asked for an update on the cause of the failure but that is in Kohler's hands and we shall see if they provide me with one.
Yeah, I think that is critical to avoid a repeat. Maybe they will investigate and provide you with that info, or they may just move on without determining the cause. But at least you now have new unit with a 10-yr warranty.

Hopefully this prompts Kohler to produce a break-in procedure of some sort, I read both the install and user manual for the new unit and it has absolutely nothing about this mentioned anywhere in it, very odd.
That's extremely odd that they don't have a break-in procedure.
Thanks for keeping us informed.


Yeah, I think that is critical to avoid a repeat. Maybe they will investigate and provide you with that info, or they may just move on without determining the cause. But at least you now have new unit with a 10-yr warranty.


That's extremely odd that they don't have a break-in procedure.
No worries, I'm happy to keep everyone informed with my 4 part train wreck :)

I thought it was extremely strange to give no break in procedure, I even tried calling their Canadian office and no one there could give me a straight answer. One told me they run the engines for 0.1hrs so they are good to go out of the box. While my unit did come with 0.1hrs on the clock I found it highly concerning.

Either way 10yrs is a long enough time to shake out any issues (hopefully zero) and since we're in a wind storm with freezing rain.....I may be in a position to do a real world test of it.
Thanks for the update…. Fingers crossed for you. Freezing/wet rain mixture here, but no wind yet. Currently salting my Hwys 😬
Amazing but justified that they replaced the entire unit. I couldn't find a break in for kohler either. Considering that rings and cam break in in a matter if minutes I think I'll go five / ten / twenty hours with oil changes.
Lastly, Kohler offered a 10yr comprehensive warranty for purchase on this unit which I happily bought.
I'm usually not big on extended warranties but not in your case. I think that 10 year was a wise purchase considering the bad luck you've had with the Kohler. Kudos.
Thanks for coming back, hopefully that latest new unit runs and works the way it was designed to. (y)
… I couldn't find a break in for kohler either. Considering that rings and cam break in in a matter if minutes I think I'll go five / ten / twenty hours with oil changes.
We just received a 40hp Vanguard engine and the following picture is of the break-in recommendations. We are attaching a magnet to the filter exterior for now while we source a magnetic drain plug.
Font Rectangle Event Handwriting Circle
See less See more
talking to my Kohler dealer / long time acquaintance, i mentioned this thread and he told me there was a run of generators with "issues" that came out of a new manufacturing facility. he said he was aware of more than a couple complete units that were replaced under warranty. i also mentioned the small amount of oil in the enclosure under the PTO side seal as well as telling him i wanted the ten year warranty. other than that everything went well and i evidently wired everything correctly.
We just received a 40hp Vanguard engine and the following picture is of the break-in recommendations. We are attaching a magnet to the filter exterior for now while we source a magnetic drain plug.
View attachment 14002
I always thought you shouldnt run a engine very hard during break in or when new
I always thought you shouldnt run a engine very hard during break in or when new
You typically increase and vary the load as the break-in procedure goes along. This is a description in a Champion manual...
Font Screenshot Terrestrial plant Electric blue Parallel


The 5-hour break-in is commonly recommended for the smaller generators, but you can do a longer break-in if you like. Varying the load by using things that turn themselves on and off will avoid a lot of the baby sitting during the break-in. Use a crockpot (with water in it), a clothes iron, a hotplate, etc. I changed the oil in mine after the first 90 minutes IIRC, and then ran another 4 or 4.5 hours before changing the oil the second time. I switched from standard dino oil to full synthetic at that time.
See less See more
41 - 50 of 50 Posts
Top