[AT] Need help with a Kohler engine CH18

[Steve W.]

Mike wrote:
> Ok guys, so I was mowing along with my old but trusty Simplicity 
> Sovereign tonight, when from out of the blue smoke started pouring out 
> the front, lots and lots of it. I quickly shut it down and opened the 
> hood and immediately saw oil running onto the ground and onto the 
> exhaust. It was coming from the front shaft that sticks out from the 
> front of the engine behind the grill. I tried to find a seal that had 
> blown but no luck. Any ideas what happened? Is it an internal seal, or 
> is this a symptom of something worse. Thanks for any help you can offer. 
> Will be trying the new picture feature, so hopefully it will make it 
> through,
> 
> Mike M
> 

Look down in the bore and you will see where the missing seal used to be.

This is a very, very common issue on this engine. The reasons are 
usually that the crank vent system is plugged, the seal itself has 
failed or the head gasket is failing which over-pressurizes the crankcase.

The head gasket failure is usually between the bore and the push rod 
channel in the head. They are thin in that location. The easy way to 
test is to pull the spark plug, pull the rocker covers, set the engine 
at BDC with the valves closed and apply air pressure to the cylinder. 
Then simply brush some oil over the gasket area in the channel and look 
for a leak.

As for the seal, You will want to do a couple things to keep the new 
seal from blowing out as soon as the engine gets warm. One is to use 
some bearing retainer on the outer edge of the seal. The other is to 
install the new seal and stake it into place with a few punch marks.

-- 
Steve W.