dennardo

I think I will do that. I am afraid that the radiator is just full of rust that won't flush out (it has to come from somewhere, right?). I had several problems with rusty bolts when taking the seats and plastic panels out and I really don't want to do it again unless I have to. In fact, the first step that should have been the easiest (removing three bolts that hold the seat back on) took a long time because the bolts were rusted to the threaded inserts set into the wood seat back. When I turned them the inserts broke free inside the seat and the only way I could remove them was to cut the bolts. I tried to use screws to re-attach the seat back, but the wood (chipboard maybe?) is very thin and doesn't hold a screw very well.

I did replace the plug. I got three of them from my local Kubota dealer because I thought if the one I needed to replace was badly corroded I would go ahead and change all three on that side of the engine block while I was in there. When I got the bad one out, it looked surprisingly good so I didn't bother with the other two. It was leaking around the edges but the plug itself looked good. I put a little high-temp thread seal around the edges as recommended by the Kubota dealer's service department and pounded it in. It was a success and there is no more leak. It did lead me to discover another problem, though. When the old plug came out, there was a bunch of rusty debris behind it that had the consistency of mud. After I replaced the plug I used a cooling system cleaner and then flushed the radiator with plenty of water. When I went to refill with coolant, I was only able to get in about a half-gallon, when the total capacity should be a little over a gallon. I was afraid my cooling system was full of rust, so just yesterday I disconnected the top and bottom hoses from the radiator, removed the thermostat, and used a garden hose to push water through the engine block. When the water first came out it was a little rusty, but not as bad as I expected. After it cleared I flushed the radiator again the same way and then put everything back together and re-filled with coolant. Again, I could only get in about a half-gallon, so I'm not sure why the capacity is only half what it should be. I'm just going to keep using it and hope it stays cool enough. I also had a non-functioning temperature gauge that I just repaired, so at least now I can see if it gets too hot.

Thanks for the reply. I've read too many negatives about sealant mixtures and I don't like the idea of a temporary fix. I also don't like the idea of being stranded if it were to suddenly get worse, so it looks like replacement of the plug is the way to go. I've been watching a few videos on removing and replacing these plugs and it seems like it is worth a shot to give it a try myself. It looks pretty straightforward once I get the starter motor out of the way and that looks pretty easy, too. I think I'm going to gather the materials and give it a try. Fingers crossed.

I recently bought a used Kubota RTV900 with a plow attachment to take care of a long, steep driveway this winter. I think it’s a 2006 and it has about 460 hours on it. The previous owner told me when I bought it that it needed an oil change but I know nothing else about how well it was maintained over the years. While going through the items in the maintenance schedule I discovered a problem with the coolant system. The coolant reserve tank was completely empty so I filled it and soon after noticed a spot of antifreeze on my garage floor. I had never noticed a leak before. I took the protective panel under the radiator off the bottom of the RTV and could see that the radiator itself, the drain valve, and all hoses and connections were dry and tight as far as the hose going into the engine block. I then took off the next protective panel that is right under the forward part of the engine. The engine-facing side of this plate was covered with a mess of oily debris that had to be scraped off and the engine itself was pretty dirty also. I cleaned things up with some paper towels and ran the engine to see if I could spot any leaks. After running the engine for only a few minutes, I saw a drop of coolant on the side of the crankcase right behind the starter motor. I wiped it dry, started the engine again, and the drop re-appeared after a few minutes. I was expecting to find that maybe the water pump was leaking, but I don’t see how that would cause the coolant to appear so far back on the side of the engine block. I can’t see anything else that might spray coolant onto this area. If the cylinder block actually has a hole in it I would expect I would see a lot more problems than just a slow leak of coolant. I am fairly handy but as I’m sure you can tell I’m new to engine work so I thought I’d see if anyone could help me diagnose this problem. Thanks.