b7100 radiator cap

   / b7100 radiator cap #1  

charlz

Elite Member
Joined
Jul 22, 2006
Messages
2,664
Location
Meridian Idaho
Tractor
Kubota B7100D
My b7100 popped a bit of steam and radiator fluid out the overflow today plowing snow. Found I was about 1/2 gallon low. Engine seems fine so I don't think I overheated it bad. I made up the fluid and the engine runs fine. Inspection of the cap shows it probably needs to be replaced, the rubber is all ate up.

I think maybe my fluid has been slowly boiling off, I never thought to check it since winter started.

Is this an 'off the shelf' part I can pick up at WallyWorld or an autoparts store? Something best purchased from the dealer? My dealer keeps a pretty good stock of items and may have it on hand bit they are in the opposite direction of work etc.

Thanks,

Charles
 
   / b7100 radiator cap #2  
Your B7100 cools on the principle of Thermocycle. Since it has no waterpump, the system is open and as engine warms the hot water rises. This cycle will eventually heat all the coolant in system and as the radiator cools it, the colder water will fall in the radiator only to be replaced by hot water from the block. This cycle eventually will cause the water to circulate thru the entire system and that's how the B7100 cools itself. So, I would definitely replace the cap with a Kubota one as it is probably set at a certain pressure for release. By the way, if your 7100 ever gets real warm it will "Whistle" at you!! That's how you know it's time to slow down and let the 7100 idle for a few. It's also a good indicator that the chaff screen/radiator fins are dirty and needs to cleaned.
 
   / b7100 radiator cap
  • Thread Starter
#3  
Mine doesn't have the whistle... but I am thinking about buying one now. Musta been lost in the 30 years of use before I bought the tractor.
 
   / b7100 radiator cap #4  
FOLLOW THE HOSE FROM RADITATOR to bottom of frame there is a metal tube bolted to frame. Itison the sme side as the injector pump right above axle
 
   / b7100 radiator cap
  • Thread Starter
#5  
robbieo11 said:
FOLLOW THE HOSE FROM RADITATOR to bottom of frame there is a metal tube bolted to frame. Itison the sme side as the injector pump right above axle

If it is supposed to be on the outside of the frame then I don't have it.

I don't think the radiator cap was the issue ($23 from the dealer). I used the tractor the day after putting the cap on and noticed some fluid leaking around the radiator side of the lower hose. I repositioned and tightened the clamp. I think the hoses are the original so if it still leaks I will replace both top and bottom hoses.

Doesn't leak when it is just sitting there, I think it needs to heat and build pressure.

Charles
 

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