I put some extra air in my rear mountain bike tyre yesterday. It uses the SLIME inner tube. It wasn't flat nor had a puncture, I was just topping it up to make the tyre a bit harder.
I cycled to work on it and all was fine. When I came out of work however, the rear tyre was completely flat. It was absolutely fine when I got to work though.
It appears that since opening the valve to pump in some air, it's been slowly leaking back out of this valve. It wasn't a problem until I did this. It's a schrader valve if of any use/relevance.
Is there anything I can do? I pump the tyre up and it just deflates again through the SLIME inner tube valve (which has spat out a bit of it's green gunk incidentally). Just seems like a complete waste of money at £16 per inner tube if it just leaks via the valve (regardless of whether it's going to seal any punctures or not).