I'm guessing that since you say the current owner has been trying to fix the water that it is not simply condensation. As someone else has already mentioned, the big cause for coolant leaking internally is O ring on the sleeve. It is about the same, except brand to the Farmall A. I had an Allis Chambers B. It was the first tractor that I got when I moved south. I got it very cheap, and compared to many other tractors, I mistakenly thought I had gotten a great deal on a tractor that once I got fixed up and running would be worth a noteworthy profit. The reality is that while the tractor is a nice little machine, it isn't worth a lot of money. When mine was finally at the point that I considered selling it, it was running, in solid enough shape but not rebuilt. I searched Craigslist throughout West Tennessee, Northern Mississippi and eastern Arkansa to see what others were selling them for. This was in 2008 or so. I found a bunch that were in almost brand new condition for under a thousand dollars, and some even came with the belly mower. If the Allis Chambers B that you are looking at were in great shape without the water and could operate in it's current state, I still wouldn't pay more than $1000 for it. I think it's a great tractor, and all. I liked mine, but, they simply don't have any cash value. Does the one you are looking at have an adjustable front end or a solid? Does it still have the 6volt system, or has it been upgraded to a 12, and what changes have they done with that if so? Does it have tractor tires or have they replaced them with automotive tires, and have they welded the wheels to the hubs? How much I would offer would depend on how great the tractor condition is in. Sorry, but if the tractor is needing repairs, and has had some off the wall things done to it, I would offer as little as a few hundred. It isn't just because I am cheap. If I put one in the shop out back, and my daughter and I work a year rebuilding it, and return it to brand new condition, I still will never get more than a thousand dollars for it. The Allis Chambers B just isn't worth much money.