1782 thermostat replacement question

[Powerman]

I am replacing the thermostat on my 1782 because it runs cool (<140 degrees). I purchased a new thermostat but the old one says it's 160 degrees and my new one is 180 degrees. Can I use the 180 degree thermostat without issues? I can't seem to find a 160 degree one. The new part number says it crosses to 15531-73010, which is the old thermostat part number. It's the Kubota D640 diesel engine.

Thanks,

Eric

[Oak]

Eric, if you look up the part on Cub Cadet here it says the Kubota part # is 1E399-73010.
https://www.cubcadet.com/en_US/conte...8f75a3ac216c/y

I Googled that number and came up with a bunch of 71*C thermostats.
https://www.google.com/search?q=1e39...t=gws-wiz-serp

Where did you get the new thermostat at? Did you check the operation of the old one in water that was heated up? I wonder if you could have a gauge issue? Let us know what you find out.

[Powerman]

Originally Posted by Oak

Eric, if you look up the part on Cub Cadet here it says the Kubota part # is 1E399-73010.
https://www.cubcadet.com/en_US/conte...8f75a3ac216c/y

I Googled that number and came up with a bunch of 71*C thermostats.
https://www.google.com/search?q=1e39...t=gws-wiz-serp

Where did you get the new thermostat at? Did you check the operation of the old one in water that was heated up? I wonder if you could have a gauge issue? Let us know what you find out.

Thanks for the reply Oak,

I guess I should have been more clear. I can't easily find a 160* thermostat that will arrive reasonably quickly and is reasonably priced. I'm in canada so that eliminates a lot of options.

I got the new thermostat on amazon.ca. The listing said it works on the D640. I didn't realize it had a different temp range than my old one until I removed my old one and looked at it. Now my tractor is apart and I want to put it back together. If the 180* thermostat won't be an issue I would like to use it. If it is going to cause an issue, I'll put the old one back and order the 160* one and wait.

I have not tested the thermostats in water.

I assume (probably a bad idea to assume) the gauge is ok because it's brand new. I installed oil pressure, temp and voltmeter gauges to replace the idiot lights with the help of this forum.

I might start over and put the old thermostat back in and verify the temperature with laser infrared thermometer gun.

In the mean time, does anyone know if the 180* thermostat is acceptable in the D640. I have it, and would like to use it if it's going to be fine.

Eric

[Powerman]

Update:

I did some more checking. I tested my gauge by boiling some water and submerging the sensor. I also put a meat thermometer in the water and compared. The gauge is pretty close.

I put the original thermostat back in and worked the tractor until it was up to temp. The tractors gauge tops out at about 150* with the 160* thermostat (i guess I was mistaken about the <140*, it's been a little while since I ran the tractor). Checking with an infared thermometer indicated 147* at the thermostat housing, so that matches up for the most part.

I also did "boil" the old thermostat and it seemed to be opening around 160* but it's hard to tell exactly when it starts to crack.

So, I could:

A) leave it be as good enough
B) Put the 180* thermostat in
C) Order a 160* thermostat

I half expected someone to tell me that I had the right thermostat and that the 180* thermostat supersedes the old 160* thermostat and that all will be well.

[Oak]

This should be the decal under you hood so as long as you're not going over 230* I'm thinking you are fine.
IMG_4466.jpg

[ironman]

A. Secure a piece of cardboard between the grill and the front of the radiator.
B. Run engine, observe temperature on gauge.
C. Trim cardboard size to obtain temp reading desired on gauge.
D. Have a brewski.

[Powerman]

Originally Posted by Oak

This should be the decal under you hood so as long as you're not going over 230* I'm thinking you are fine.
Attachment 114478

Thanks Oak, for the image. I do not have that sticker. That's helpful.

[Billy-O]

You're in Canada where you probably rarely see scorching weather temperatures often that a 180 degrees thermostat is probably fine.... Maybe even better than a 160 thermostat. At 180, you are still fairly well below the max temp you want to see. There could have been issues in the past with engine cooling if radiator had gotten plugged (inside and/or outside) that a PO had opted for a lower thermostat. Worth looking into this!

[jsoluna]

180° is the correct temperature range for the stock D640 thermostat. Pic attached of the service manual data.