Simple question I have collapsed rad hoses (1 now)

Replaced T it cracked after hose repaclement
Replaced upper hose it had a bubble that was the original source of the problem

I have put my old rad cap back on in case the new one has failed - still need to confirm this is not the issue.
Thermostat is about 2 months old Black LR
Engine temps are perfect

Any other probable causes I should check ?

 

Are you losing coolant? The only reason I can see a radiator hose collapsing is because when the system is pressurized coolant is evacuating but as the vehicle cools air is not allowed to enter and equalize the pressure. A one way valve of sorts.

 

@ahab Not that I can see,but a bad rad cap does the same thing as the system pressures air escapes then the cap closes and does not allow air back in. There was no moisture under the Disco this am and no smoke out of the exhaust and the filler cap is good but it is possible I did not get the system properly filled yesterday after the T fitting cracked.

 

Loosen cap and run cap 1 turn loose

 

If you've already changed the cap and still have same issue (which is normally the issue)...check tube that runs across the top of the radiator for blockage. Is the throttle heater hoses by-passed or connected to throttle body housing? You have a partial blockage that is forbidding fluid to return to reservior.

 

@Extinct thanks for the suggestion

@The Deputy Swapped cap and did a quick test seems ok, fired some canned air through the return line (from the expansion tank side) it is fine and the expansion tank filled with displaced fluid. Throttle body is bypassed.


So it is looking a like a bunch of a small simultaneous failures - I have annoyed the Disco gods somehow.

 

I installed new genuine hoses, the two plastic pieces and radiator last year and bypassed the throttle body (plugged lines). Also have a new cap. Lines are collapsed a bit after I come home from high altitude (I live near sea level) and cold. I don't have any coolant losses. Coolant level looks elevated, when cold. I just open the cap to let some air in and the coolant level goes back to normal.

 

I went through this and had to get sent TWO expansion tank caps until finally getting one that worked. Couldn't believe that was the fix.

 

lf you're saying you capped off both lines from lower intake and reservior...you should connect the two for correct/better circulation in the cooling system.

 

I understand that this is not the correct circulation anymore, but the flow doesn't get altered and the amount going through that line is negligible, about 2% of overall coolant flow.