Overflow pipe to ground - MOT Failure?

craig_jdm · Post by **craig_jdm** » Sat Apr 13, 2013 9:53 am

why dont you fit a bottle but low mount it under the bumper bar if the reason you dont want one is for looks

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sat Apr 13, 2013 11:04 am

I agree better to have it one (little reason not to). Especially as this is running a tuned engine/custom rad setup (don't know how it will behave).

Nothing disconcerting at all about mine not using the expansion tank. As I said in previous posts, it all depends on the condition of each specific cars cooling system and the conditions it operates in.

If the system stays fully in balance during operation, it won't need to vent/suck back. For occasions when the system goes out of balance (builds up excessive pressure, which could still be within normal operating parameters) then it uses the expansion tank.

My UKDM happens to operate (for the moment) at one end of the operating parameters.
Other people's (including I think my JDM) operate somewhere else within them (coolant system age and condition/driving conditions etc).

Hope that explains better? The whole point of my original comment was just to say, if yours doesn't happen to vent, yes that CAN be normal, so don't lose any sleep over it!

NB: I'd expect a failing rad cap to result in excessive venting (spring pressure would drop over time, meaning it wouldn't hold as much pressure and would vent early)

Supermarine Blues · Post by **Supermarine Blues** » Sat Apr 13, 2013 2:29 pm

wurlycorner wrote:Ref my other post - the level in the radiator level has never dropped in 3 years (that I still check of course )

Don't tempt fate...

Angus · Post by **Angus** » Sat Apr 13, 2013 4:50 pm

Aye, wurly, I see where you're coming from.

Your experience has made me think a lot more about the cooling system, that's for sure!

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sat Apr 13, 2013 4:59 pm

I think there's too much thinking about them going on here tbh