B7100 cooling system info

John C · Aug 15, 2009

Greetings All,
Does anyone out there know what pressure radiator cap is supposed to be on a B7100 the original cap had 0.9 and some Japanese writing on it. I'm afraid to just get one that appears the same for fear of over pressure and blowing hoses my local Tractor Supply store has several caps that look similar ranging from 4 Psi to 16 Psi. I'd also love to know the normal operating temp range for this model. I checked the temp with an infrared thermometer at several places top tank of radiator read 204, bottom tank read 134 degrees F. Head between injectors read 210 F. Just wondered if anyone knows if this is normal temp since I have coolant dripping from rad overflow while working the tractor. maybe a new cap would cure this if temps are normal!

ipz2222 · Aug 15, 2009

Temps sound right but I'm not sure abour rad cap pressure. Guessing around 8 lbs.

B7510 · Aug 18, 2009

I believe the 0.9 represents bar 1 bar = 1 atmosphere of pressure, about 14 psi. 0.9 is 13.5 psi.

Here is a link to an online converter. Just plug in 0.9 and select bar then convert to pounds per square inch.

http://www.onlineconversion.com/pressure.htm

Hope this helps

aquaforce · Aug 18, 2009

You should not have less than 10 psi cap.

John C · Aug 20, 2009

Thanks Everyone! I PM'd Vic and he confirmed that the cap should be 13PSI and he also reviewed my temps and confirmed that they were OK! So I carried my old cap to my local Autozone and they sold me a new cap for $4.95 that matched my old one. My local Kubota dealer was going to have to order one for $24.95 plus freight. I ran home topped off my radiator with 50/50 antifreeze mix and installed the new cap. I then fired her upand worked ehr for about 15 minutes once again I noticed coolant dripping from the overflow tube I assume that this is normal since I topped off the rad while it was cold and I didn't leave any expansion room so hopefully once it has expelled enough coolant to make up for expansion it will stop. I'll keep you posted!

jimtulloch · Aug 21, 2009

My B7100 opeates with 13lb cap and runs at between 65 - 70 degrees celcius ( operating in Queensland Australia where daily temp is quite hot.) as this model does not have a water pump and operates on a thermosyphon system, the water level when hot would be something like 1" down. Essential to flush the radiator perodically and hose out any debris from the radiator fins. Use good quality coolant mixed 50/50. Keep the screen in front of the radiator clean. I have fitted a temp gauge to mine by soldering a socket into the radiator top tank on the right hand side to fit the electric sender switch.Prior to this I used a cooks thermometer with a 4' long flexible capillary and probe,I taped the probe on to the top of the radiator. Great little workhorse tractor.

John C · Aug 21, 2009

Update!
I worked her a short while last evening and it appears that the coolant dripping from the overflow has stopped as I suspected it would! I really like jimtulloch's idea of adding a temp sender and guage to give you a heads up if the radiator grille should become blocked instead of learning about it the hard way! Sounds like a neat mod for someone to write a how to article or post a video about! Hint Hint.

Dan_R_42 · Dec 12, 2010

Jim Tulloch would you happen to have any photos of how you attached your temp sending unit. Would love to do this to my B7100.

Thanks, Dan

kuboman · Dec 12, 2010

Mr Gasket sells a rad cap with a built in thermometer. I have several and it takes the guess work out of wondering what the temp is

Dan_R_42 · Dec 13, 2010

Great idea... Thanks Kuboman. Would you know what the part number is that we need for the B7100? Did Google search. Seems that they have 6 caps for 13 PSI. Not sure which would be the correct unit.

Dan_R_42 · Dec 15, 2010

After more research it appears that there are actually only two 13# radiator caps to choose from. Reason for the six part numbers is they offer each of the caps in three trim colors (Red, Blue & Silver). Ya gotta love the performance & racing world...

The two actual choices of cap are Domestic or Imported. Found local parts supplier that has the Domestic in the warehouse. Should have it by the weekend. Will let you know the part number if it fits the B7100 radiator...

Dan

hodge · Dec 23, 2010

Dan_R_42 said:
After more research it appears that there are actually only two 13# radiator caps to choose from. Reason for the six part numbers is they offer each of the caps in three trim colors (Red, Blue & Silver). Ya gotta love the performance & racing world...

The two actual choices of cap are Domestic or Imported. Found local parts supplier that has the Domestic in the warehouse. Should have it by the weekend. Will let you know the part number if it fits the B7100 radiator...

Dan

Any update? Did the cap work, and what was the # if it did?
Mark

Dan_R_42 · Dec 25, 2010

B7100 Radiator cap update... The Mr Gasket Domestic cap Part Number #2470S fit perfectly, and works great. It is a 13# cap. The "S" on the part number stands for silver trim ring color.

Here is a link to Mr Gasket to the cap I'm talking about:

http://www.mr-gasket.com/ProductDet...ajID=300&minID=3008&selection=&minselection=3

They come in 3 trim ring colors so an "R" red, or "B" blue, in the part number will also work, just depends on which model they have avail in your area.

A dash gauge would have been ideal, but this is not a bad compromise to have an idea of your operating temp of engine. Yeah, you do have to pop the hood to check it, but, hey it works great...

Merry Christmas & Happy Holidays!!! everyone in OTT land...

Dan

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B7100 cooling system info

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