New Holland TC40DA A/C

A/C working this morning, Blowing hot air two hours later,can anyone tell me how to troubleshoot the A/C?

I by no means am an A/C expert. I do know that most (all?) a/c systems have a safety catch on them that if the system runs low on freon it won't allow the compressor to kick in. I would start by testing to see if you blew a fuse to the A/C compressor. Then I would start by testing to see if it is low on freon. The other day I was at Advance Auto Parts and they had a tester there that would test your freon level. I want to say it was around $50 or so. That would tell you if it was too low to allow the compressor to kick on. Then if you need to add, you will have to see if it continues to work or if there is a leak somewhere.

You pretty much covered it Jim.

I'm sorry, I don't know how much experience you have on your tractor or what kind of conditions you're working so if it seems that I'm insulting your intelligence, pardon me.

On my Kubota, if the radiator, heat exchanger and oil cooler aren't kept spotlessly clean it can lead to it starting to overheat, the a/c blowing hot air and oil warning lights starting to come on. When mowing in dry, dusty conditions I have to take a break after about 4 hours and let it cool down, then take off the side panels and wash everything out real good. In fact, when that a/c starts blowing warmer air is one of the clues that it's time to clean her out. With small cabbed compacts there is just so much stuff crammed under the hood all trying to gulp air to try to stay cool.

That's where I would start but if that doesn't help, I'd go with Jim's advice.