Anyone install an oil cooler on a BX?

[techguy2]

Being in Houston, my little BX seems to run Hot during the summer mowing season.

I do all the normal suggestions, including making sure the radiator is clean by using an air compressor and a long air gun nozzle and frequently cleaning the screens.

It almost always runs right in the red during july/august. The local shop says run it that way, it is ok. Personally, I really hate to think I am taking a chance on it. Last summer, I ended up taking the cowling off and it helped get the temp down a little.

I was thinking that a oil cooler would be a simple way to fix it.

I have 200 hours on my BX and mow 2 acres of former pasture with it.

 

[timswi]

I've run mine in the occasional 100 degree heat cutting 2 acres and never buried the temp in the red. Oil cooler might help, but the air flow though the cooler might be a problem. Not enough speed. not sure if there is enough room to use the engine fan.

Checked the thermostat?

 

[techguy2]

I've run mine in the occasional 100 degree heat cutting 2 acres and never buried the temp in the red. Oil cooler might help, but the air flow though the cooler might be a problem. Not enough speed. not sure if there is enough room to use the engine fan.

Checked the thermostat?

Yeah, that was my first thought, and replaced it with about 50 hours on it.

No change.

The shop said that 'they just run hot', which didn't sit well with me.

I was thinking about mounting the oil cooler on the side, not near the radiator.

 

[PILOON]

'I was thinking about mounting the oil cooler on the side, not near the radiator."

And could U not add an electric fan(s) that draws outside air? (thinking computer 12 v 'muffin fans' here.)

Also have you tried removing the thermostat to see if that improves things.
Seems lots of rice paddy tractors simply did not have thermostats.

 

[rdsaustintx]

Hey Techguy, welcome to TBN.

I'm a little west of you (Williamson County) with a BX. I mow when it's hotter than h3ll here and my temp gauge rarely goes past the middle. I am wondering how accurate the temperature gauges are. Hate to see you worry over a $2 gauge, but agree the shop saying running in the red is normal is total baloney.

Figure out some way to objectively compare temps, PM me this summer and we'll do a little test. I have all kinds of IR cameras, non-contact thermometers and stuff for work, but all we need is a cheap means of comparing how hot we are really running. Could do it with thermal crayons or one of those stick-on strips on the upper radiator header. Probably more accurate than a factory gauge (with no marking other than a cartoon beaker)...

Just a thought.

Russell in BubbaLand

 

[radioman]

First of all - lets take a step back and look at this situation here. What is the temp gauge for ? It is NOT for the hydro oil on the BX's. Its for the water/antifreeze coolant. installing a oil cooler for the hydro will NOT cool the engine temps. The temp guage doesnt even monitor the oil temps, but we should have one-- but let's not get side tracked on that.

I have a few questions- What were you running to cuase it to get that hot? how long ? what RPM's ? rated rpms for PTO or are you running it slower then 3k ? If the gauge gets that high into the RED, then something is wrong for sure. Don't beleive the shop answers, where is his answers coming from as a fact from kubota, not opinion or experience? When was the last time you replaced the thermostat ? did you flush and refill coolant every 2 years like the manuals states ? dumb question here, gotta ask this one - is the fan belt ok, when you open the hood do you feel blast of air blowing out ? Did you replace the air filter yet?

Most of my questions are silly, but can help a long ways in figuring out the problem. try to answer these questions and we can go from here.

 

[Volfandt]

techguy2, I wouldn't think that adding an external heat exchanger/oil cooler (HE) would hurt at all, matter of fact I think it's a very good idea.
I'm addressing the HST but one for the engine wouldn't be bad either, same principles applies.
These HST's really heat up their fluids when they're working hard and thats what most of us do, work them hard. Then when you facter in that the same fluid is getting worked hard operating implements then the idea of additional cooling has mucho merit.

A couple of considerations.
1) Kubota designed these tractors to work at their optimum with everything operating at a certain temp so we don't want the auxillary cooling to kick in until needed.
2) Space is at a premium in the engine compartment and since the primary powerplant that produces the most heat resides in there, thats not the optimum location for a cooler.
Those are few that comes to mind and I'm sure theres many more.

To address #1, and as an example, Harley Davidson as well as many aftermarket producers make an external oil cooler for their air cooled engines that also have a thermostatically controlled bypass valve which allows the cold oil to by-pass the heat exchanger (HE) which allows for normal warm-up time. I'd say the temps are similar (around 180 to 200 degress F) so that could be a consideration for a premade solution.

To address #2. To get the maximum cooling, air will need to be forced through the HE
but one would also function in cooling by just providing static surfaces for the heat to disapate but this isn't optimun.
a) If one were to locate the HE in the back, air flow wouldn't be as prevalant unless it was mounted up on the ROPS and the tractor is moving. So a powered electrical fan to move the air would be optimum.

b) under the tractor would be the worst location UNLESS additional protection can be fabbed up and encased around it. We wouldn't want it to be as suseptable as the OEM fan.

c) mounted on the front, outside of the cowling would be a good location and a mount for the HE could be fashioned around/onto/in place of the OEM grill guard (if equipped).

The easiest place to tap into the hydraulic system would depend upon where the HE is to be mounted. Up front it would be off of the FEL feed, in the rear it would be off of the hydraulic block, on the TLB's it would be off of the hydraulic loop.

Many large trucks/buses have external power steering oil coolers which are similar in size to the HD oil cooler and I've seen the bypass valves sold separately in motorcycle mags.
A small heater core would also work.
In any case good luck and if anyone should accept this task, let us know
Dave

 

[DavidAubke]

This seems to be a common issue with Bs and BXs. Mine has always run dangerously close to the red when mowing in full sun above ~85 degrees ambient. Doesn't matter that the radiator and screens are spotless and coolant is clean and topped-off. I suspect some temperature gauges are inaccurate or improperly calibrated for the operating range. It does concern me that some don't have this issue and report that their gauges stay right in the center.

 

[Sam Mac]

For what it's worth. You could try Red Line Water Wetter. I use it in my race car and the stuff works.
Red Line Oil 80204 Red Line Water Wetter Supercoolant

 

[Tom_H]

It should not be red-lining, regardless of the temperature, if both screens and the radiator itself are all clean. I have mowed and brush hogged in 115 degree F here in the CA Central Valley. Chaff from the weeds is easily sucked under the first screen/cowling and can fly through the second screen to embed itself in the face of the radiator itself. I sometimes have to rub chaff off the outer screen every 90 seconds. If everything is clean and working properly, I will get close to, but not cross the red line. If anything is off, it will red-line.

You have been keeping everything clean. Other possibilities are contaminated coolant, a failing thermostat valve, bent fins on the radiator, a failing water pump, a bad temp. sending sensor, a temp dial not correltly calibrated, or something electrical between the two. Do you ever hear water boiling in the radiator when you shut down? If so, you know something is not right. Once boiling, the pressure is very dangerous. I would pay to have someone else check it out. I would rather pay for that than pay to replace a warped head, blown head gasket, some other engine work, or especially deal with the danger of exploding hoses and super heated water.