The Forestry Forum

General Forestry => General Board => Topic started by: 47sawdust on December 26, 2022, 04:55:47 PM

Title: Kohler 8.5 RMY leaking oil
Post by: 47sawdust on December 26, 2022, 04:55:47 PM
Owned this generator for 5 years,less than 300 hours.Never an issue.The motor is a Kohler CH-20.
It ran for 72 hours straight in our latest power outage.
It has developed a big oil leak.
Don't know where to start.
Help appreciated.
Will call Kohler in Wisconsin in the morning.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: bigblockyeti on December 26, 2022, 05:20:18 PM
Quote from: 47sawdust on December 26, 2022, 04:55:47 PM
Don't know where to start.
Where is it leaking from?
Title: Re: Kohler 8.5 RMY leaking oil
Post by: doc henderson on December 26, 2022, 05:37:58 PM
The worst leak we had on one time was my wife having to start it while I was at work.  came home to my wife in her robe and house shoes and two neighbors trying to help.  It would not start so I had her check the oil as it was low oil protected, and she did not get the cap back in.  If this is in a big, enclosed chasse, it may be harder to track down.  may have to do some cleaning first.  but check the oil plug, and dipstick if it has one.  and the filter area.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: GRANITEstateMP on December 26, 2022, 06:54:33 PM

After checking Doc's suggestions, I'd check the oil cooler lines if it has an external cooler
Title: Re: Kohler 8.5 RMY leaking oil
Post by: sawguy21 on December 26, 2022, 08:07:38 PM
What @doc henderson (https://forestryforum.com/board/index.php?action=profile;u=41041) said. You need to clean it up the best you can and watch for leaks after it starts. With any luck it is just the fill cap or a valve cover gasket.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: barbender on December 26, 2022, 08:47:09 PM
Check your crankcase breather. Idk about your particular engine, but a lot of breathers will freeze shut in cold weather operation. Then crank pressure builds, and oil will push out of your main seals. I've had that happen on an 8hp Honda, and a Chevy Duramax😊
Title: Re: Kohler 8.5 RMY leaking oil
Post by: 47sawdust on December 27, 2022, 07:25:12 AM
Thanks for the replies.It is an enclosed unit so today I'll pull the covers and clean it up and proceed from there.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: 47sawdust on December 27, 2022, 11:41:48 AM
Pulled the covers off,removed the air filter and the found the breather tube surrounded by what looks like congealed mayonnaise.No cracks in the tube will give everything a thorough cleaning before re assembly.
Waiting for a call back from the dealer I have a service contract with but I know his list is long.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: barbender on December 27, 2022, 11:47:42 AM
The congealed mayo can be caused by an oil/water mix (mostly water). The conditions we just came out of are perfect for icing up those breathers, but if it is an enclosed unit I would think it would hold enough heat to keep it from icing. It will be interesting to see what your dealer says.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: doc henderson on December 27, 2022, 06:05:16 PM
was the oil level low?
Title: Re: Kohler 8.5 RMY leaking oil
Post by: 47sawdust on December 27, 2022, 07:15:18 PM
Doc,
Yes the oil level was low.I sure hope I dodged a bullet there.I cleaned everything up changed the oil and filter set a drip pan under the crank seal and gave it a test run.
It ran well with no obvious leaks,but time will determine that.
I am embarrassed for not being more vigilant about the oil level.
I don't know how people get away with leaving generators running unattended for long periods of time.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: barbender on December 27, 2022, 09:08:51 PM
 If it was from the breather being clogged, you could've checked the oil before you started it and had it shut down from the low oil level safety 2 hours later. Once they build pressure, the oil pushes out the main seal quite quickly.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: 47sawdust on January 25, 2023, 08:21:27 AM
Well as it turned out the crankcase pressure built up and pushed the dipstick loose slinging oil over the whole engine.
An extra push is needed to fully seat the dipstick.This is an older model and the dipstick design has been changed.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: barbender on January 25, 2023, 12:49:27 PM
If it is pushing the dipstick out, either your breather is plugged, or you have a lot of compression blowby.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: sawguy21 on January 25, 2023, 02:04:38 PM
That's right, there should be a slight vacuum in the crank case of a healthy engine.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: 47sawdust on January 25, 2023, 03:47:03 PM
I am not experienced with internal workings of standby generators.I spoke to a local Kohler  Generator
dealer who services all types of standby generators.We had a 3 day power outage in this area recently and he said he saw a lot of generators of all makes with filthy oil enclosures after continuous use.His impression was it was caused by atmospheric conditions.
The dealer who services my generator says this model of kohler engine was known for blowing oil out the dipstick and that Kohler changed their design.His opinion was it was better to blow it out the dipstick than blow the crank oil seal.
Heck if I know!
Title: Re: Kohler 8.5 RMY leaking oil
Post by: Machinebuilder on January 26, 2023, 08:55:07 AM
I had a similar thing with the Kohler on my mill. it looked like it was leaking oil but it was blowing out the crank case breather.

A friend suggested it had a stuck ring and to pull the plug and fill the cylinder with diesel, let it soak then turn it over a few times, put the plug back in and start it.
Make sure to change the oil before starting it.

It seems to have worked.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: Al_Smith on January 26, 2023, 09:30:20 AM
I don't know if this would apply but I've seen the crankcase breather tube plug up .Some so badly the pressure would build up to the point it pushed oil right past the crankshaft seals .One case on a Tecumseh engine it blew the seal out . What caused that I have no idea .
Title: Re: Kohler 8.5 RMY leaking oil
Post by: sawguy21 on January 26, 2023, 11:47:38 AM
I saw that frequently. The end of the tube ices up in the airbox and pressure builds in the crank case. I would let the hose hang free (and risk destroying the ozone layer all by myself) then duct tape the hole in the airbox to keep snow out.
Title: Re: Kohler 8.5 RMY leaking oil
Post by: Al_Smith on January 26, 2023, 01:59:52 PM
Those crankcase tubes have been used a long time .I've got some Briggs engines I know go back to the 60's that have them .Some go into the breather some to the manifold/carb .