Radiator Overflow Resevoir

[avi8tor]

I was checking my coolant level in my L2800DT and I noticed that it doesn't have a reservoir for the overflow. The overflow tube just hangs down from the filler cap neck. I checked the parts manual and it doesn't show a reservoir. Has anyone added one or is there a need for one? The fluid level is a little low, not by much though.

 

[LRP]

read these posts about the overflow and thermosiphon cooling
http://www.orangetractortalks.com/forums/showthread.php?t=3277

 

[avi8tor]

I forgot to mention that my kubota is a 2010 model and has a water pump yet is doesn't have an overflow reservoir. The overflow tube is open on the end and doesn't have a "whistle".

 

[LRP]

http://wiki.answers.com/Q/How_much_is_the_boiling_point_of_coolant_per_one_pound_of_pressure
this link talks about the boiling point of coolant under pressure.
the boiling point is raised 3 deg for every lb of pressure. sooooo
the OT with thermo syphon uses 13 lb rad caps =39+ 212 = 251 deg boiling
point of coolant. my overflow tank is just about done .
Louis

 

[avi8tor]

Thanks for your response Louis. Back during the summer when temps around here were 100+ I ran a bush hog for 7 hours straight - the temp gauge never went above normal (white dot just above the "C"). I checked the coolant before I started and it was full. Now after running for 7 hours with the temps below freezing, it looks to be about a couple of pints low. The temp gauge still at the normal "white dot". I may look at adding an automotive type overflow just to see how well it maintains the coolant level. Just wanted to see if someone else had tried this and what results they had.

 

[Marty394]

It may not be as easy as adding an overflow tank. Automotive systems with an overflow tank also use a different radiator cap. The cap will have two seals. One will be at the lower end of the cap stem to seal the smaller internal radiator neck. The other will seal the upper, larger portion of the neck. There is also a one way check valve in the lower portion of the stem. The two seals and valve allow the radiator to remain sealed and create a vacuum when it is cooling down. The one way valve allows the coolant back into the radiator when it is under a vacuum. The system on your tractor was not designed to have an overflow tank, and therefore probably doesn't have a double sealed cap. Also on the system that you have the coolant level should be checked when cold. As a usual rule of thumb, the level should be at least covering the cooling tubes.
It doesn't need to be full to the bottom of the filler neck. If it is full when cold, the coolant will expand when it warms up and will be purged from the system via the overflow hose. When the system cools down it should be at the desired level. So there you have it, sorry for the long winded version!!

Bob

 

[LRP]

thanks for shareing your expertise Bob. ur 100% correct. it won,t work
with the bota rad cap, however i just pulled the rad cap of a old chev truck
and the physical dimentions are the same. now for the bad news for me,
when i took the rad cap of the bota just now, part of the ear fell of. it had been broke for some time. so i have my work cut out for me towmorrow.
i will try to silversolder it back on. u can see the broken ear on the left
cap wich is the bota. the right cap is the chev and it has the top seal
and the check valve that the bota one don,t. i,ll be haveing nightmares
about the cost of a new rad tonight.

 

[avi8tor]

Thanks for the reply Bob! The level of coolant is above the cooling tubes. I didn't think about the double sealed radiator cap. My radiator cap is the single sealed cap. I am used to automobile radiators that stay full all of the time. I'll probably just leave it as is for now. The temp gauge seems to work very well.