Halfords stuff is fine, as long as it is the same basic 'make up' as in there. You can check on their website by putting the reg number in, although I get a second opinion from a bit of interweb searching.
More importantly, you need to ask yourself why it needs topping up? It has to be going somewhere to need refilling. Check the reservoir cap is tightened properly and that the seal is intact and good. Check the engine bay for any signs of leaks or weeps.
I have two BMs with extremely stiff reservoir caps (so stiff they often need pipe grips on to move them). My B48 was low on coolant when I got it (despite a 5,000 point check by the supplying dealer!
). I found that the cap hadn't been tightened up properly as it was so stiff, so coolant was gradually evaporating.
All good things come to those who wait. I'm really impatient which explains a lot.
F31 320i. Good car.
E89 20i Now fully dried
Z3 'free litre'. Project and a half. Complicated!
Mazda3 sold
Tatty old R56 Mini Cooper. Money pit!
