help with cooling/radiator/waterpumpp

little advise needed, was running the golf on the drive after giving it a clean, hasn't been driven much as doing a little work on it. after about 5-10mins one of the hose pipes explodes (literally ripped apart). i believe it is the hose running into the water pump (will add picture tomorrow, when back with the car).
its a simple fix to add new pipe, but my question is why did it happen? it was stationary so probably overheated, but should it of built up so much pressure?
any help appreciated, cheers aidan

Check the electric fan is working, if not it could easily overhead and burst a worn old hose. Other issues could be faulty thermostat or waterpump.

Thanks, I'm not sure if the fan kicked in, but ill check the thermostat to see if it works. I'm pretty sure the water pumps working though.

Easy way to check pump is
Take top off expansion tank and water should be poured in via the pipe to tank from radiator. 

Thanks ill give that a check aswell 

fitted the new hose topped up the water/anti freeze. ran the engine to check the water pump, unfortunately no flow from the radiator tube, which i believe is because of the old thermostat which i will change when i get a chance. and because no water is flowing through the radiator it isnt kicking in. but now i know where the issue is i should be able to sort it soon.
heres my dog gem giving me a hand

More interested than some apprentices I've had !

So today i fitted the new thermostat, ish? 
Got to use the pit. But unfortunately when removing the bolts one was seized and the head snapped off leaving the thread stuck in the water pump. 
I still managed to change it and ran the engine once refilled. But had no joy with the radiator kicking in. And still not sure about the waterpump, I think the best thing to do is fit another one or just go to the garage and see what they say

Can I change the waterpump without removing the engine?

yes, alternator needs to come off then you have easy access.

if nothing is coming out of the thin hose it could be blocked, take it off (carefully!) and blow thru it. give the nipple on the radiator a good poke to ensure its clear

Cool, everytime I sort one but another bit breaks, this is the best way to learn though. 

got new waterpump, was gonna fit it it, then it dawned on me, i forgot to order the new bolts   hopefully it will come on monday so i can fit it. then will be driving again

finally got around to removing the old waterpump, removed the radiator as well and cleaned it up and flushed the whole system. hopefully when i run the car next, all should be well and good. if not the only other thing to change is the fan itself if the motor is bust

When you fill the system with water and antifreeze it's worth pouring some into the top radiator hose going into the head until its full then put it back onto the radiator then slowly fill the expansion tank as its really easy to get an air lock. 

i never bother doing that and have never had an issue. just fill the tank to the top, run engien with cap off and squeeze all hoses i can lay my hands on. rev engine now and again and keep topping up the tank as required.

top tip for getting 50/50 mix, pour in 1 neat bottle of coolant, then fill bottle with water and pour that in. pour half the 2nd bottle of neat coolant into the first, then top both up with water

This is the longest ongoing thing I've done. Fitted everything the other day but battery was dead and I forgot to charge the jump start box. Finally got around to chargin the battery overnight and it started first time, gave it a little drive and guess what the fan still doesn't work once up to temp. So I guess I need a new one, or sensor what starts it? Would that be why it doesn't work?

the fan is controlled by the thermoswitch in the rad. it wont switch on until the gauge geats to around 3/4, which isn't easy to get to in weather like this!

to check the radiator fan and wiring unplug the thermoswitch connectors and bridge the red to the red/black then red/white (or if its a single speed, bridge the 2 wires together) if fan runs then wiring is all fine, look at the thermoswitch. if not, check the fan wiring. its simples really, red wire is permanent live and brown is earth.

but yeah, as i say the fan wont turn on until around 3/4 so it might just be engine isnt getting hot enough

Cheers for that I will give it a look at after work