should I block radiator in the winter?

[DONOTDELETE]

Winter is coming. Does my B7300 have a thermostat? If it does't (or even if it does) should I block the radiator in the winter. I'm thinking of all those trucks with the front blocked off. I've allways heard that diesels like to be warm. I've been reading some of the threads about the hydrostatic oil getting to hot, but shouldn't it also be kind of warm, otherwise why do we warm our tractors prior to using?

[TomG]

I'd block part of my rad if the temperature wasn't coming up to the normal operating range, otherwise I wouldn't. Yes, tractors like to be warm when working--hydraulic oil included. Me too, except I don't have a heated cab.

[JimBinMI]

Rob7300,

What kind of speeds are you running at? I thought that blocking the radiator kept your radiator a little warmer when going 50-75 mph down the road. What effect would it have at less than 9 mph at top speed?

JimBinMI

We boys and our toys!

[Keoke]

Robb, all engines should at least be warm enough in the winter to vaporize the condensation that forms in the crankcase. If you have an engine without a thermostat you can try this home made stat. Find a short length of copper pipe that fits snug into your top radiator hose. Get a 160 degree stat trim the outside edge to fit into the copper pipe and solder it inside pipe. Drill a hole about 1/4 to 3/8 inch on side of stat flange (not in center moving part) this is needed to keep water circling in block when stat is closed. If you can't do one big hole do a few small holes on the outside edge to equal a single hole. Place copper pipe in upper rad hose(stat pellet side to engine) as close to block as possible and secure with hose clamp. It's not a good idea to run a gas or diesel engine without a thermostat, especially in the winter.
regards,
george, keoke

[DONOTDELETE]

Thanks for the great answers. No I don't go down the road at 50-60 mph. I was wondering if new Kubota's come with thermostats? On the front of the engine where the radiator hose connects, it sure looks like a thermostat housing, But last winter it didn't seem like the engine got very warm. Short of taking the housing off to see what's in there I was hoping there was someone out there that all ready has and knows what's in there

[Bird]

Robb, I can't say for sure on the B7300, but my B2710 parts manual shows a thermostat in that housing that just looks like an ordinary automotive type thermostat, so I suspect that you have about the same thing.

Bird

[TomG]

My Ford 1710 has a 185-degree thermostat, and I imagine most liquid cooled engines do. One advantage of a liquid cooled engine is that their service lives tend to be longer. They can be engineered from an assumption of fairly constant operating temperatures (at least according to a dealer who sold my a Honda generator). There wouldn't be a very constant operating temperature without a thermostat.

My '89 F150 ran cold the first winter I had it. The thermostat was stuck partially open. It also gained temperature going up grades during the summer.

[DONOTDELETE]

since my B7300 doesn't have a temperature indicator I am baseing last winters cold engine on touch. The engine was just barely warm. If it indeed has a 165-185 thermostat then may be it also is stuck open. I hate to start taking my new (110 hrs.) Kubota apart just to find out whether the thermostat is working. I guess it's better to do it now then when it's freezing out.

[Kelvin]

The B7300s predecessor, the B7100, did not have a water pump nor a thermostat (it had a "thermo-siphon" cooling system. On the B7100 the alternator is mounted behind the cooling fan and looks like a water pump (there are wires going to the unit and there is no water bypass hose).

I'm nearly 100% positive that the B7300 has a different cooling system; it has a water pump and thermostat. First of all, you'll probably notice an alternator mounted somewhere else besides the back side of the fan. Second, you'll see a small water bypass hose in addition to the two large hoses connecting the engine to the radiator.

AIR FLOW: I cannot be very convincing here. My older model B7100 has a "front-to-rear" radiator air flow design (I have to clean grass off the front grill). My newer model B2150 has a "rear-to-front" radiator air flow design (I have to open the hood and clean a screen on the back side of the radiator). The B7300 is a newer design than either of my Kubotas, so it could be either way (my best guess would be rear-to-front).

THERMOSTAT: The shop manual for my B7100 covers a lot of different size Kubotas (mostly '70s and early '80s). At a quick glance every model with a thermostat specified a 180 degree thermostat.

Hope this helps.
Kelvin

[Bird]

Robb, like Kelvin said, my B2710 has a thermostat that's supposed to start opening at approx. 180 degrees (completely open at 203). And the way we used to tell whether a thermostat was stuck open was to remove the radiator cap when the engine is completely cold, start the engine and rev it up just a bit and see whether you can see any movement of the water in the radiator. It should not start to move (circulate) until the thermostat opens, so if it's moving when the engine is completely cold, the thermostat is stuck open (unless someone has simply removed the thermostat and thrown it away which was not uncommon 40-50 years ago).

Bird