Outdoor Power Equipment and Small Engines - 20 HP Kohler Oil Leak/Walker Mower

I paid a local service center to repair a oil leak on 20 hp Kohler. No Joy! The oil seems to run down the side of the engine on the left side as you are setting in the seat. I have been out of the country on OEF and started it yesterday. It only leaks when the engine is running. Ready to start mowing here in Tennessee. Can anyone tell me where to look?

check the valve covers. if you dropped the hopper before the seat you may have broken the stud on the cover.

Many thanks for the help! I took the heat shield off and it seems that the oil is coming out of the rear main. Probably no quick fixes! Is it either pull the engine and fix the main or just keep putting oil in it?

Is there not enough clearance to replace the main seal with the engine still in place? It's not normally a very hard job to perform, unless the engine compartment is so crowded that removal is required.

I had the rear main seal replaced at the dealer along with a new muffler. I fired it up yesterday and it is now leaking worse; it is actually spraying out of the rear main worse than before. Any suggestions? Is this a breather problem. I am sure the service technician is not going to want to see this Walker back. Is it time to find a new service technician.

If you paid to have it fixed, take it back. It may be a bad seal, or the spring may have popped out of it when it got installed. It might have gotten cut, or they may have scarred the craqnkshaft during removal of the old seal. In any case, I would not touch it, just in case the crank surface IS scarred. If you remove the old seal and see a scar, they will claim you did it when you pulled the seal. If this is the only problem you've had with them, I wouldn't switch service centers yet. It may be an honest mistake, or something out of their control like a bad seal. Give 'em a chance to stand behind their work.