Coolant Leak

[Martyn]

I have got a leak into the drivers side footwell (on the left hand side of it, I think) of coolant after I leave the car overnight, occasionally. An eggcupful appears on the rubbermat some mornings. Why does this happen when car parked and not when system under pressure? Any clues? Martyn.

[kiwi]

That would be the Heater Matrix Tap I would suspect! Have a look above the steering colum should see a couple black pipes running from Heater to Bulkhead and abox like thing with couple of levers etc. The biggest clue probably be the staining as its leaking.

OR it could be but less likely the drain pipe from the heater that has moved.

OR if you have a Sunroof a dislodged drain hose BUT thats more likely to be nearer the right of the footwell.

My guess is the Heater Matrix Tap the location fits.

[mnde]

If it is the heater matrix, it's not necessarily the end of the world! This happened to me with my first BX: the telltale coolant smell and suspicious puddles on the floormat... I found that tightening the four (surprisingly untight) bolts securing the tap assembly to the matrix, and applying a cautionary smear of silicone sealant around the joint, cured the leak. It's a bit of a fiddly job though, involving grovelling around in the footwell and trying to keep a torch directed upwards at the right place....

Try running the car to operating temperature with temp control on cold, then turn it all the way to the hottest setting, get your torch out and check/feel for drips from the tap - to - matrix joint above the pedal box. If you don't know what you're looking for, there's a decent picture in the Haynes manual.

Good luck!

Mark.

[Bazza]

Well done guys....? now that you have gone and MENTIONED this topic, MY '85 BXGT has decided to come out in sympathy with you..!!!

Started her up yesterday and promptly got my left foot showered with slightly rusty water. LOTS of it. huh, Good job I am past (just ) my Hippie days of pachoulie oil and sandals eh..?

Thanks for the tips though and I will delve into it all another day. I have been flushing the system out profusely lately as the previous owners had never heard of a/freeze and conditioners etc. Initially, I flushed the main rad with a hose at full bore, for well over 15 minutes and the water was still just wet rust colour. I guess I also flushed away the heater matrix or some important parts of it, (the parts that keep the water in!!)

Bugger, had to fire the D Special up instead and take that out for a drive...sigh.... (well it was the next one in line on the driveway...)