Export thread

I have a Cub Cadet ZTR with a Kohler Command 23 hp engine. I recently did my annual oil change + filter. Everything was fine for a short while after doing this. A couple of days ago my son went to cut the grass and stopped because oil was profusely leaking out around the oil filter area. The first thought was that the filter was not screwed on tight enough. We re-tightened, and it still was leaking whenever it was running.

My next thought was that the gasket from the previous filter must have been left on the oil filter face plate or the gasket on the new filter has dislodged. I drained the oil and took the filter off. Everything was as it was supposed to be. I even went ahead and placed a new filter on it. As soon as it started up I could see oil quickly dripping off the bottom of the oil filter face plate.

As best as I can tell, the leak is coming from behind the oil filter face plate. The manual suggested a blocked breather line could overpressure the crankcase and cause a leak. I checked and I can easily blow through the line.

The oil filter face plate seems integrally attached to the block. Is there some way the screw on nipple is leaking from behind the face plate?

Other suggestions?

Thanks

Tired-n-dusty

Behind the oil filter is a Allen head that is the same thing you screw your oil filter on can see if that is loose I have seen that happen when taken the filter off. If this unit has a oil cooler equipped this all has to be replaced. Also have seen the o-ring behind them leak as well as the oil filter plastic adaptor crack and leak as well. Bet you find your issue after removing the filter and tightening up that Allen head might cure your issue.

Luffydog said:

Behind the oil filter is a Allen head that is the same thing you screw your oil filter on can see if that is loose I have seen that happen when taken the filter off. If this unit has a oil cooler equipped this all has to be replaced. Also have seen the o-ring behind them leak as well as the oil filter plastic adaptor crack and leak as well. Bet you find your issue after removing the filter and tightening up that Allen head might cure your issue.

Click to expand...

Is the Allen screw behind the oil filter face plate? There is about a 1/2" gap between the face plate and the block. Or is it in on the outer face of the plate? (see orange arrow on attached file).

I do not have the optional oil cooler. I am assuming the O-ring you refer to is the one that would be between the the oil cooler unit and the face plate? Is the oil filter plastic adaptor part of the oil cooler or is there something else I should be looking for?

THanks for your help

Tired-n-dusty said:

Is the Allen screw behind the oil filter face plate? There is about a 1/2" gap between the face plate and the block. Or is it in on the outer face of the plate? (see orange arrow on attached file).

I do not have the optional oil cooler. I am assuming the O-ring you refer to is the one that would be between the the oil cooler unit and the face plate? Is the oil filter plastic adaptor part of the oil cooler or is there something else I should be looking for?

THanks for your help

Click to expand...

I did drain the oil again, removed the filter and saw where the threaded nipple for the oil filter has an Allan wrench fitting. I checked and it is rock solid tight

So your unit doesn't have the plastic

Luffydog said:

So your unit doesn't have the plastic

Click to expand...

Where is the plastic you are referring to? If it is associated with the oil cooler, then no. There is the milled aluminum face plate that the oil filter tightens down onto via the threaded nipple

Degrease the area put a new filter on then mist water over the whole area and dust liberally with talcum powder to make a nice white coating.
Allow it to dry then run the engine and watch for where the oil starts to bleed through the talcum.
Oil can run along join lines and appear a long way away from where the leak actually is.

There is a small chance that your block has a hole in it ( casting defect ) although most makers pressure test them way above operating pressures.
Some photos of the region and some more showing the oil bleeding out would be most helpful.
The trick is to watch it and turn the engine off as soon as you see the first oil bleed before the area gets swamped.