temp gauge

[Bill Radford]

I recently completed some work on my 641. Among the things I did was to flush, drain and replace the coolant with a 50/50 mix of prestone green and distilled water. In addition, the radiator vanes were cleaned and the assembly repainted.I noticed that the fan was mounted backward: Ie pushed air forward through the rad instead of pulling air backward through the rad.I flipped the fan over the right way.
Before I did these things, the temp gauge would read in the green range(or middle) after the machine had run a while and warmed up.Now it barely gets out of the cold section of the gauge even if you drive it a few minutes, even though the air temp is in the 90's here.
Be advised that I have not run the tractor with a load such as a plow or bushhog,but only up and down the street.
One of my friends told me that the thermostat may not be opening and closing,however I doubt that because I shot the temp with a laser thermometer and the lower hose was 120F, the upper hose 165f and the cyl head around 220f.Seems that rad is doing its job and I'm not loosing any coolant through the overflow.
Could it be possible that the capillary tube for the guage has some junk in it that was stirred up when we flushed?
Any ideas will be appreciated.

 

[Tracy Brown]

You have either a pusher fan or a puller fan. Turning it around will not reverse the direction of air flow. One way or the other may make the fan more efficeint though.

 

[Ultradog MN]

Thanks Tracy.
I was trying to think if it would make a difference to turn a pusher or puller around and then read your post. You are correct. Reversing the fan blade will Not reverse the air flow.
Bill, if you do have a pusher fan you could get the price of a couple of puller fans out of it.
Guys on the N board love them kinds of add ons.
Advertise it here that you will trade for a puller fan. State that you want to trade fans and the trader must pay the shipping both ways.

 

[Bill Radford]

Checked the parts book..it is a puller fan.
Still have a question about the temp readings.

 

[Tony Jacobs]

Hello Jerry , The only problem with doing that is there is many different PULLER and PUSHER FANS depending on year , spacer on the pump or fan blade and with the later tractors type of water pump . Many later tractors have had their water pumps changed to a later design with 4 long bolts and Aluminum spacer just like a Ford car/truck and have different blade counts depending on application . I know of 2, 3, 4, 6 blade pullers and 6 and 8 blade pushers off the top of my head alone . Thanks Tony

 

[BruceR TN]

I often wondered about that. Mine (1955-850) is a pusher but seems to work well. I hadn"t ever seen a pusher configuration before I got the tractor. I assumed it was to keep the radiator warm if running in cold weather.

 

[Larry NCKS]

(quoted from post at 13:40:27 07/23/12) Checked the parts book..it is a puller fan.
Still have a question about the temp readings.

Bill, the temp gauge capilary is not open to the system, therefore, flushing the system will not harm the capilary.

It sounds as though you have a temp gauge that just normally reads low, given the rad hose and engine temps you cited. I would say your system temps are normal.

 

[NoNewParts]

Bill, sounds pretty normal to me on these
super-cooled tractors, now that you have the cooling
system all sorted out.
My similar NAA's run within a few degrees
of the thermostat spec all the time.(some have aftermarket gauges with numbers)
I've never seen 'halfway' on the gauge, even plowing
worked one hard in 90 degrees leveling fresh made trails this week.
gauge right at about 175-185 degrees all the time (180 thermostat)
wintertime, it won't even make that unless I block off the radiator.

 

[john in la]

The capillary tube is a sealed system with either gas in it so you can flush away. If the system ever gets a pin hole where the gas escapes the gauge will not work at all.

Your system sounds pretty normal.