wanted to make sure before starting. i was gonna take off my s5 bac and clean it. if i go by haynes book, it says i have to drain coolant. is that really necessary?

 

either drain the coolant or clean up the mess when you start removing small coolant hoses

 

I don't think it's really necessary to drain it all, but you will lose some when the hoses come off. Have plenty of rags handy, and a jug of coolant to replace what you lose.

OR... If you haven't drained and flushed your cooling system in a while, you could hit 2 birds with one stone.

 

Turbo or NA? I'm not sure about the NA, but turbo you can take the two screws off + not even leak a drop.

 

same with a na

 

No need to drain the coolant unless you have to remove the BAC with the pipe still attached to it. Only reason for that is if the screws are stripped out...

 

what pipe?

 

if you look at the BAC valve itself, there is coolant hardpipe screwed to the side with two philips screws. that's what the coolant hoses attach to. It is possible to remove that coolant pipe, but the screws do strip out. I would try to replace them with allen screws or something if you get them off. Or consider eliminating the BAC coolant hoses altogether.