Oil & Fuel Does HST oil warm up if I am not moveing?

[farmacist]

If it is 10 degrees out and I start my tractor and let it "warm up" for 15 minutes does the HST circulate the HST oil all through the circuit, through the HST filters, and through the sump storage supply? Or do the foot pedals need to be pushed before the oil will circulate? thanxs Frank

 

[MadReferee]

Assuming the HST has a common tank/sump with the implement hydraulics, the answer is yes. The main/implement pump is always pumping fluid thru the cicruit as long as the engine is running.

 

[Soundguy]

I'm not 100% familiar with the design on thae hst systems, but yes.. their should be oil circulation goin on even in neutral.

Soundguy

 

[SkyPup]

Yes, it certainly is circulating.

Don't try dismantling one of the high pressure lines on the HST while the engine is on......

 

[Raddad]

Why would you want towarm up a tractor for 15 minutes?

 

[daTeacha]

When I lived in Newaygo County in Michigan, the rear lift on my 8N would take about that long before it started working properly after a long night during a "Good Ole' Michigan Winter". Until the thing got warm, the lift would hardly move at all. I learned pretty quickly to make sure the blade was sitting on wood blocks and not the ground after it froze in place one night when the temperature dropped from about 35 to 5 by morning. The tractor couldn't lift it or pull it out by driving forward or backward. It is not fun using a pick-axe and a sledge to get your blade freed from the ground. If I set it too high, it took a long time before it would lower, too.

 

[jinman]

Frank, Mad is right about the hydraulic oil being in a common sump and that the oil is circulated by the main hydraulic pump. It is also circulated by the charge pump of the HST (the pump that supplies oil to the inlet side of the HST), but at limited pressure not to exceed 300 psi. The pressure is probably much less if you are only at 1000 rpm idle speed.

The HST pump is in the neutral position because of the pedal being neutral. Very little fluid is pumping through the HST and what is being pumped is doing no work. The same is true for the main hydraulic pump. There is fluid flowing throughout the open-center system, but it is not doing very much work.

To really speed the process of heating up, you could press the HST pedal with the brake set or you could raise and lower your implement and FEL. However, if you are going to do that, you might as well be moving and working. I would say you should warm up the tractor a couple of minutes until the engine oil is getting slightly warm and then drive or work the tractor to heat up the hydraulic oil. You would have to sit at idle a long time to heat up 10 gallons of hydraulic fluid that is just circulating through an open-center system without doing some work.

 

[schmism]

I would say you should warm up the tractor a couple of minutes until the engine oil is getting slightly warm and then drive or work the tractor to heat up the hydraulic oil.

Thats what i do... warm up the engine for a few min (usually while im pluggin in the compressor to air up that one front tire with the slow leak) doing a check of fluids, gathering up the tools ill need for the project im about to head out to do.

Then i get on and pick a painfully slow pace, set the cruse and what normaly takes 15 sec ride to get to the edge of the pasture now takes 2 min.

by then things have started to warm up....

 

[farmacist]

So just because our temperature guage shows that our motor has warmed up we should not assume that our hydraulic system is warm....I think some of us have thought that we could go full power as soon as the temp gauge was up to temp. I wonder if that is why some of us have blown our hst filter gasket?
Thanks again, Frank

 

[jinman]

So just because our temperature guage shows that our motor has warmed up we should not assume that our hydraulic system is warm....I think some of us have thought that we could go full power as soon as the temp gauge was up to temp. I wonder if that is why some of us have blown our hst filter gasket?
Thanks again, Frank

Yep...that's right. The engine temperature gage has very little to do with the temperature of the transmission or the hydraulic reservoir. That's why many of us would like to have a separate gage for hydraulic temperature. In the summer when we've been working the tractor hard, we only know the engine temperature. Someone did do some measurements with a handheld probe this last year and found some surprisingly high temperatures at various locations around the reservoir and the main hydraulic pump.

I'm embarassed to admit that I've forgotten who made the measurements or even if it was here or in the general forums. You might find it with a search.