Takeuchi with Kubota engine

[rentthis]

I have a Takeuchi skidsteer with a Kubota engine. The machine has 300 hours and is running hot. The upper radiator hose is sucked flat.
We have replaced the radiator cap and it still sucks flat. We have checked everything but the thermostat. Could it be as simple as a bad hose?

 

[BruceP]

First - some facts:

• The cooling-system should have POSITIVE pressure within it while engine is running.
• As engine cools, a NEGATIVE pressure (vacuum) is generated.
• The radiator cap has TWO valves within it
  1. Pressure release (engine hot... to prevent over-presurization)
  2. Check valve (cooling down... allow coolant to be sucked from external reservoir )

I will assume you did NOT see hose sucked flat with running engine so I will conclude you observed a system which is cooling off.

It sounds to me as if there is no free flow from reservoir to check-valve in the cap.... hence a vacuum forms and sucks the hose shut.