A commercial landscaper's Hustler Super Z came into my shop, with a liquid cooled 26HP Kawasaki (FD731V-BS00). I noticed that the engine was loose on the frame, so when I tried to tighten it down, I found that there was damage to the mounting bolts and also to the threaded holes at the base of the engine. In fact, 3 of the 4 bolts were broken off inside the aluminum, but not before the prolonged movement of the engine against the loose bolts basically destroyed the mounting holes. I had to remove the engine in order to inspect the mounting holes well enough to determine what could be done. I decided to drain the oil before turning the engine on it's back, but when I opened the oil drain valve, nothing came out. I double checked the oil level, and there was indeed oil inside (but low, and black). So I removed the oil drain tube from the sump, assuming it was plugged. It was indeed plugged, but what I saw inside the crankcase was something I've never before encountered in my shop -- black jello. Uh-oh. As I used an air hose down the dipstick tube to force some of this sludge out, I noticed a little bit of bright green antifreeze coming out of the crankcase as well. So after I got the sump off, I noticed some additional damage. First of all, the oil pump filter was broken and the screen destroyed. Not sure how that happened. Second, I noticed that the PTO bushing had a really rough spot, presumable caused by a lack of lubrication paired with the side load caused by the belts.
I'm trying to put a story together, to explain to the customer what has happened. I plan to call Kawasaki on Monday, but I thought I'd give you guys something to chew on as well. Besides, I really don't want to wait until Monday.
One more detail that seems to be important, now that I've seen inside the engine. I feel sorta silly for not recognizing this clue at the outset. There's a beeping alarm on the mower that I think is supposed to sound whenever you start it up, but it's supposed to go away after startup. But it kept ringing as long as the engine was running. NOW I realize that it was probably an alarm caused by low oil pressure, but I didn't think of that at first. The customer was aware of the alarm, but I don't know how long he operated it like that.
So, was the sludge caused by water leaking into the oil? Or is that kind of black sludge only caused by heat and a lack of maintenance? I don't have too much experience with the liquid cooled engines, so I've not seen a lot of the problems associated with them. I need to do some more checking, but I believe the engine is repairable with a new sump, a gasket set, and a few other parts. I took one of the rod caps off, and both it and the rod journal looked perfect.
What are your thoughts?