My bottom radiator hose sucks in when I rev the engine - are these hoses supposed to have a coil in them to prevent this? I bought it new from a dealer and there was no coil in it.

 

Yes, get a hose with a coil in it.

 

...or do a favor for one of your mates, and flush his cooling system for him. When you remove the bottom hose to clear out the radiator of debris, you could conveniently "lose" the spring...

C'mon - we won't tell...

Actually, any coil spring about 40mm 'round will do, as long as you stretch it out to elongate it and make sure it's at least large enough to stay out of the radiator and water pump.