First, thank all of you guys who really know what you're talking about on this forum! I've learned a lot from you already, but this time I'd like some input about my TB260. It has a Yanmar 4TNV86CT-PTB engine which runs great, but it tends to keep getting hotter when working, even if not working really hard. It will make its' way to 225* in about 20 minutes in 50ish* ambient, and quicker when warmer. It cools back to 172 in about 7 minutes at idle. So far I've topped off coolant and hydraulic oil and cleaned radiator, which wasn't very dirty, but did show some dirtiness on the hydraulic cooler side. The thermostat opens at 160 and isn't stuck open. Radiator looks like new on inside, from what I can see. Machne as about 1500 hours and is in otherwise good condition. Any insight will be greatly appreciated. Is t'stat right one? I'd think it would be at least 185 or 190*. Thanks in advance!
Year of the machine? Has it sat for a long time? When was the last coolant flush? Passages could become clogged with gunk or rust. Have you checked fan belt tension? Belt can loosen and fan (and therefor water pump) won’t spin at correct full rpm.
So we have 2 Tak260s. They have a tendency to run hot, the radiators do get some dust and debris stuck to them and need to be blown out with air and then washed out with hose best you can. Also, we have found that if you can spin the fan without the belt turning, your belt is shot or too loose. I’ve also read somewhere on here that some folks have changed to a slightly smaller idler pulley to speed the fan up a bit. It really like s to climb quick when it’s really hot out, the AC is on and you’re working it flat out. There is a lot of hydraulic heat that is generated when running that little bugger and it’s all packed into that machine without a lot of space.
The machine is 2018 model. The fan will spin by hand without turning the pump, but not really easily. I'll tighten the belt and replace it when I can pick one up. I'm used to running the crap out of my equipment without having to worry about overheating, so this is aggravating. Thanks for the help. I also wonder what temp the tstat should be . I'd expect about 195 or so. Also, radiator looks like new on inside, it has not been sitting for any time, and coolant is green with no sign of rust.
The coolant absorbs the heat. The airflow through the radiator core is what cools the coolant.
one you get the radiator clean, put some screendoor screen in front of it - facing the wind. I use the little neodymium magnets from out of hard drives to mount. anyway, the screen will help with debris larger than the holes and it's a hell of a lot easier to clean than the radiator itself.
I just want to thank all of you guys, especially Tags, for guiding me on my efforts to make my TB 260 run at normal temp. I finally had time to tighten the belt, which is no easy task, and that seems to have fixed the problem. Thanks again!
Congratulations Tags on figuring out how to fix KenMac's overheat without spending any money. Owner experience goes a long way. Simon C