Fan / Thermostat

Barryh · Jan 31, 2016

I have been slowly doing maintenance to my PT getting it ready for spring. I Just cleaned out the gas tank and installed new filters and gas hose. I am cleaning the carb and have a new fuel pump on the way. Also just bought a new marine water separator with filter the same setup that came with the Kohler. Of course could not get the original they stopped making them but the new one works perfect.

I have been watching for the hydraulic cooler fan to come on while the tractor sets idle. So far have not seen it kick in. How long before it is suppose to come on after the engine is running idle?

I hooked the old fan up directly to make sure it still works. It does so if it's not coming on guessing this is the thermostat and I will need to order a new one..

How many of you have just wired the fan up directly so it is always on.. I would think the fan would burn out quicker this way but would keep the hydraulics and engine cooler thinking I like that idea better.

Any one done this and how did work out. Not sure where I can get another fan, my guess I will have to modify with an upgrade this one when it burns out..

davesl708 · Jan 31, 2016

The hydraulic fluid may not get hot enough to need the cooling fan when at idle. Working the hydraulics should warm the fluid up and you can test the temp sending unit to see if it is still working.

cqaigy2 · Jan 31, 2016

Maybe hit the sensor with a heat gun?

Barryh · Jan 31, 2016

davesl708 said:
The hydraulic fluid may not get hot enough to need the cooling fan when at idle. Working the hydraulics should warm the fluid up and you can test the temp sending unit to see if it is still working.

I checked it after using it for a few hours lifted the steel lid and it was not spinning. Not sure if it had been running and cut off or not wouldn't be able to hear it with the tractor running.. Not a big deal though, as long as I know the fan still works. I'm sure I can find the part somewhere.. Thanks for the reply

Barryh · Jan 31, 2016

cqaigy2 said:
Maybe hit the sensor with a heat gun?

I took apart the wire connectors and they were fairly loose. I cleaned them and put them back on tight. Waiting on a fuel pump right now as soon as I get her back up and running. I might try that if it still does not come on. Thanks..

joshlee · Jan 31, 2016

I have the subaru engine and the White Rodgers heat relay opens up at 110 degrees, I think. To run the fan continuously I don't think would be a good idea, because that oil temp has a sweet spot. Being too cold causes more friction, so the oil heating up isn't a bad thing. So having the fan turn on at the right time according to how the engineer designed the hydraulic system would seem the way to go, to me.

Barryh · Feb 1, 2016

joshlee said:
I have the subaru engine and the White Rodgers heat relay opens up at 110 degrees, I think. To run the fan continuously I don't think would be a good idea, because that oil temp has a sweet spot. Being too cold causes more friction, so the oil heating up isn't a bad thing. So having the fan turn on at the right time according to how the engineer designed the hydraulic system would seem the way to go, to me.

Think I will just pull it out and find another one online.. Makes sense thanks..

Scrambler82 · Feb 1, 2016

As said even the new electric fans in cars don't run all the time.
If they do then you need to check them out.
Find out what the working temp is and get some water, heat it to that temp and see if the thermostat conducts electricity, if so then it isn't the it.
Then find out working temp of oil, see if it matches the working temp for the thermostat.
Why buy new if what you have is working.
Also, if the working temps of the thermostat and the oil are not matched or you want to lower the on temp, then consider getting a thermostat with a different working temp range.

woodlandfarms · Feb 1, 2016

I don not have your machine but in the winter I am hard pressed toget the cooler fan to run unless I am stump grinding or something serious with the hydrualics (which would be a million post holes or mowing).

joshlee · Feb 1, 2016

Yeah, same here. Mine doesn't turn on hardly at all. One of the things I would like to ask an engineer down at tazewell is, what is the leveling off temp for the hydraulic oil on the PT-425s ? Just out of curiosity.

woodlandfarms · Feb 1, 2016

Should say on the thermostat. 180 to 190 I think. If I remember correctly there is an optimum temp for oil, and I think it is 160 to 200.

menchhofer · Feb 1, 2016

If I remember correctly the 1430 temp control on the fan is dryer thermostat or something like that. Replaced it years ago.

SpringHollow · Feb 1, 2016

I would love to know the replacement part for my thermal switch. I will have to remove it and look some time.

Ken

Barryh · Feb 2, 2016

woodlandfarms said:
I don not have your machine but in the winter I am hard pressed toget the cooler fan to run unless I am stump grinding or something serious with the hydrualics (which would be a million post holes or mowing).

Really haven't spent that much time watching to see if it turns on..

I just noticed after I brought it home that it never saw it come on, even after running it for a long time. But if it takes a lot of working in the heat to make it switch on then maybe it still does work can't hear or see it from the seat.

I've been in upgrade mode working on other more obvious things. Since I have a nice low hour machine I just wanted to make sure my hydraulics are staying as cool as possible when working this summer in 90+degrees temperatures..

Being an older tractor just kind of suspected it might be bad. Some of the wires were loose and dirty tightened and cleaned everything up. I guess it is possible there is nothing wrong with it. When I get more time will have to get it really heated up and then lift the hood to see if it comes on.

Thanks for all of the comments a big help.

ponytug · Feb 2, 2016

If you are concerned that the fan is functional, you could always bypass the thermal switch to see if the fan comes on.

All the best,

Peter

MossRoad · Feb 2, 2016

Since you know the fan works when connected to 12V and doesn't work when connected to the thermostat, and depending where the fuse is in the circuit, of course (you checked the fuse, right?

), then you're correct that the thermostat is most likely the problem. When mine was working it would always come on about 20-30 minutes after plowing snow, which was rare with the PT because I was usually done in 10! :laughing:

I noticed my thermostat stopped working about 3-4 year old. So I just hook it to 12v and start the tractor and go in warm weather. I don't bother with it in winter. Some day I'll put it on a switch.

I also tied a 6" piece of orange caution tape to the fan shroud. When the fan is running, it blows up and I can see it on.

Barryh · Feb 2, 2016

MossRoad said:
Since you know the fan works when connected to 12V and doesn't work when connected to the thermostat, and depending where the fuse is in the circuit, of course (you checked the fuse, right? ), then you're correct that the thermostat is most likely the problem. When mine was working it would always come on about 20-30 minutes after plowing snow, which was rare with the PT because I was usually done in 10! :laughing:

I noticed my thermostat stopped working about 3-4 year old. So I just hook it to 12v and start the tractor and go in warm weather. I don't bother with it in winter. Some day I'll put it on a switch.

I also tied a 6" piece of orange caution tape to the fan shroud. When the fan is running, it blows up and I can see it on.

Fuse is good, need to try the orange tape then drive it around.. For now waiting on a new fuel pump will here by Friday.. Didn't realize until I read all of the comments that it takes that long to come on. My last PT didn't have a cooler. Good tip on the tape thanks..

Barryh · Feb 2, 2016

ponytug said:
If you are concerned that the fan is functional, you could always bypass the thermal switch to see if the fan comes on.

All the best,

Peter

Thanks Ponytug first thing I did, it does come on.. :thumbsup:

MossRoad · Feb 2, 2016

I put an in-line spade connector on my fan wire. So I have to open the engine cover to connect it and again when I shut it off. On the down side, if I forget to connect it, I can get the thing pretty hot. On the plus side, it makes me look in the engine compartment before and after I operate the machine, which I should be doing anyway.

Barryh · Feb 3, 2016

MossRoad said:
I put an in-line spade connector on my fan wire. So I have to open the engine cover to connect it and again when I shut it off. On the down side, if I forget to connect it, I can get the thing pretty hot. On the plus side, it makes me look in the engine compartment before and after I operate the machine, which I should be doing anyway.

I was also thinking about a switch. Someone on here said it shouldn't be on all the time. During the winter I would agree. But in extreme heat conditions with my 180.. I always had the feeling it it was running way too hot.

In fact I had a powerful outdoor fan I would leave running in the yard. I would pull the PT up next to it to help cool everything down after working hard in the heat.

Leaving it on during those times seems to make sense to me.. Not only for the cooler but maybe to help circulate more air to the engine.