Before I came on holiday last week turned and gave the FF the bifters past amstupid woman in a MX5 going super slow. Didn't notice any problems untill I got to my mums 3 mins later when I noticed all the coolant coming out underneath! Opened the bonet and the hose off the alternator had come off loosing most of the coolant. I pushed the hose back on and gave it a tug an it came off. Pushed it back on with the clip and appeared tight. Re-filled and drove home no problems. Could it just be a coincidence that as I've booted it the water pump has given enough pressure to pop the hose off? In recent months the Rad has been changed and various under bonet activity. Could it be the hose has just worked loose? As a precaution I've got a new top hose just to be safe? Any ideas of causes other than a HGF or just wait and see what happens?

probably loose in the first place rob, especially after the rad change... ... - .- -.




Y. O. L. O.
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As per Scarey, I'd guess it was already loose and you booting it gave it a helping hand.

I've burst two pipes and 2 header tanks - every time it's been whilst I pull onto the drive. I'm sure sure yours popped off just as you pulled onto your mums drive - if you'd actually driven for 3 minutes with no coolant you'd know about it.

As you slowed down the engine would still have been very hot from the booting, yet you've slowed right down which causes the coolant to super-heat in places increasing the pressure in the system.

The other culprit could be your thermostat isn't openning fully and caused a build up of pressure. 

Good to hear! Would rather have 20 hoses and tanks than a HGF! from what I've read when the heads go and hoses come off it's the big one on the rad end normally isn't it?

Both times for me it was the bastard hose behind the engine that goes to the heater matrix.