HST temps

[espacef1fan]

So I see a lot of you mention that bush hogging with a HST tractor is bad because it builds up heat.

This formed a few questions in my mind:

1) How are we measuring the heat?

2) Are we doing controlled tests comparing to gear tractors?

3) If it is a problem, are we finding ways to increase cooler capacity?

 

[4570Man]

The HST tractor isn’t going to overheat the trans bush hogging. That’s pretty easy work for the trans.

 

[k0ua]

Lots of people make up lots of BS every day. You need to be asking LD1 who commercial bush hogs with a hydro tractor. All day every day.

 

[Beeenvenue]

There are zero restrictions or cautions listed in any owners manual I know of relating to this. I bushog with my hst in very high thick grass in north Texas with temps 95-105 and decent humidities. Keep the radiator screens clean and use your dang machine! They are made to work and work hard. (No issues and no visible or olfactory evidence of fluid breakdown)

 

[oldnslo]

My guess is that more heat is generated by the PTO gears spinning in the oil inside the transmission than the HST generates. Like others have stated keeping the radiator and oil clean of dust and debris is the main concern. Same problem with geared tractor

 

[5030]

They all have external oil coolers anyway. Key to removing excess heat is of course keeping the airflow path between the grill and the rad clean. Plugged up intake screens reduce air flow which reduce heat exchange which cause hot oil (and a hot motor too) and don't forget to blow out or replace the air filter regularly.

 

[ericm979]

It's not any more load on the HST than driving the same slow speed without the mower running would be. The PTO is driven off the engine or the clutch, not through the HST.

But keeping the radiator clean is important. Mowing puts more chaff in the radiator than other tractor work. Keep an eye on the engine temp gauge.

 

[rScotty]

So I see a lot of you mention that bush hogging with a HST tractor is bad because it builds up heat.

This formed a few questions in my mind:

1) How are we measuring the heat?

2) Are we doing controlled tests comparing to gear tractors?

3) If it is a problem, are we finding ways to increase cooler capacity?

1. Some tractors have a gauge that reads transmission oil temperature. It can't be difficult to add a temp gauge if this is a concern. It might be interesting to see what it would say. Get one with degrees; not just low/med/hi.

2. Not that I've heard of. Almost all tractors use a common sump for the common transmission/hydraulic fluid. Our HST tractor has a large radiator up front that cools this fluid, I assume that gear drive tractors have the same trans/hydraulic radiator....but maybe it is model specific or even an option. Again, I've not seen this discussed. Overheating does happen, but it isn't limited to HST & bushhogging. That's actually pretty light use.

3. Well, first we have to decide that it's a problem. If so, then more cooling would help.
But from what I've read here on TBN it seems to me that overheating tends to be more of an operator problem than a tractor problem.

To that I'd add that it is possible to push any machine so hard that it runs too hot. The cure for that problem is to back off, not to increase the cooling capacity and keep going full throttle. .

So I guess my own bottom line is I haven't heard evidence that convinces me that overheating with bushhogging and HST is a mechanical problem. But if you think it will be, then adding a temperature gauge and additional cooling seems a reasonable thing to do. If it were me, I'd add a temp gauge, work on optimizing the airflow over the existing cooler, and then see what the temp gauge says about that.

 

[RalphVa]

Just because it's making a lot of noise (including the engine), it doesn't not mean that it is working very hard. Our VW TDI made very little noise, and it worked harder than the engine on my JD 2025R.

 

[ericm979]

Often the HST version of a tractor comes with an oil cooler that the gear model doesn't have, or has a large one. So the factory is already dealing with additional heat.