I started to bleed coolant on Sunday, it was a fairly warm day and a lot of stop start traffic, but I've isolated it to what seems to be the drainage screw, either that or the welds around it. Question is, does the standard plastic screw have an o-ring with it...I would assume it does, as mine does not, and it's leaking, although i can't think why it would start now. If it does what size is it so I can pick one up on the way home from work. It's a alloy radiator, so it's not the plastic end tanks before someone chirps up.
I had the head snap off my drain plug, just leaving the threaded portion in the radiator and of course it leaked. This could be your problem. Can't help with what size though sorry.
The one ally rad sitting in my room from the ZRATED GB, the O ring measures 11mm internal bore dono if that helps
As a precautionary measure it's also a good idea to use thread tape on the plastic screw, heavy duty tape is only like $2 from bunnings
had the same problem with mine ( ASI 56mm radiator). Inspection found that the neither the radiator, nor the plastic bung, were grooved so as to seat the o-ring properly (flat surface on flat surface allowing the o-ring to flex out). For peace of mind, I replaced the o-ring with a fibre flat washer instead.
Yes, same radiator. I noticed the lack of a groove. Also noticed what was left of the oring on the bleed screw, which I replaced at the same time and taped up. I dare say I will be replacing the oring everytime i need to drain the radiator.
