Leak in 51 Plate Mini One

[Hannah.Gibbs]

Hello all,

Having real trouble tracking down this leak... Can't see any evidence of a leak in the door or window (i.e no water or water marks on plastic).

I seem to be getting puddles of water in my rear passengers footwell and also sometimes the odd patch in the front passenger footwell.
This problem has now made my car smell damp yet I have am still to find the leak...

Anyone else had this problem and found the solution or have ANY tips for me... Your help would be MASSIVELY appreciated...

Thanks
Hannah

[MINIAC]

Does your MINI have a sunroof?

Have you checked for water in the boot?

[Hannah.Gibbs]

Quote: Originally Posted by MINIAC (original)

Does your MINI have a sunroof?

No it doesn't have a sunroof

[MINIAC]

Other areas from which leaks are common is the seal of replaced windshields, heater matrix and upper brakelight on rear hatch.

[Hannah.Gibbs]

It doesn't appear to be from the windscreen... Can you advise how I would check the other 2? If it was the brake light would I not have water in the boot? There is no water other than in the passenger footwells front and back... Mainly the back though.

[MINIAC]

Yes, you'd have water in the boot if the leak was in the rear hatch.

If your MINI is parked on a slope the the water could flow front to back.

I found this post regarding heater matrix leaks ...

Quote: Originally Posted by mab01uk (original)

I have a spare complete MINI heater unit out the car (for retro fitting air con) and there appears to be no way for water to enter the car other than from a leaking heater matrix which is near the passenger footwell on a RH drive MINI.
Realoem.com diagram of heater unit (LH drive unit shown with cabin /pollen filter on RH side):-
RealOEM.COM BMW R50 One 1.6i ACTUATOR, HEATER AND AIR CONDIT.

Check also for leaks from windscreen and front pillars, etc.
Other signs of a leaking heater matrix are often smells of antifreeze in the car and steaming up of the windscreen with the heater blower on hot.
To replace matrix:-
Battery & battery tray has to be removed on a One/Cooper (also probably ECU) but I think only the Air cleaner if a Cooper S, to gain access to the matrix pipe unions on the bulkhead, then the matrix can be pulled out from inside the passengers footwell (behind a black plastic cover) 3 Torx screws hold cover, top one is difficult to get to. Replace the 2 'O' rings on the metal matrix pipes when refitting pipe clamps to new matrix, also bleed all air from the system when refilling.
At least the dash does not have to come out like some cars so labour price should be more reasonable...........or if you are a reasonably confident DIY mechanic you could get the Haynes manual for the full details.

[Hannah.Gibbs]

Thanks will give that a go on the weekend. Although my car doesn't smell of anti-freeze and doesn't steam up when heater on hot... But worth a try Thanks for your help

[idoney2]

I have a 51 MO and had the same problem-flooded passenger footwell. I traced the leak to two possible points (on mine anyway!).
If you look at the door seal near the door hinges you will see the main drainage guides stop a few inches below the "knee" bend on the seal. I watched in the pouring rain one day as water flowed out of this guide and onto the lower part of the seal. The water sapped behind this and into the car.I put a bead of silicon sealant at this point to deflect it away.Why on earth they designed it like that is beyond me The other point is under the plastic "gutter" the seal can allow water behind and down into the car if it collects dirt with age. I cleaned the dirt from behind this and applied a thin layer of silicone sealant here too. Car is bone dry now

[Hannah.Gibbs]

Thank you so much. Going to look at everything you have suggested this weekend. Fingers crossed its the door seal Be a quicker a cheaper job
Have a nice weekend

[mega-mini]

first - for the boot leak, one should cheque the grommet for the rear windscreen wiper. the water seeps in and collects in the hatch interior to spill out when you open the hatch.

second - for front passenger footwell puddles, i am currently working on an answer to this one. my mini does not leak at all even in torrential rainstorms. however i collect overnight a good half pint of clean clear water the first thaw after a frozen spell driving on snow. is it possible the passengers cabin air filtre collects condensation and when it melts off it is too much for typical draining? or does snow collect under the car and leak in upon melting. again extremely heavy rain... dry as can be.

Mega-Mini Molalla Oregon

[MiniBazzer]

Quote: Originally Posted by MINIAC (original)

Other areas from which leaks are common is the seal of replaced windshields, heater matrix and upper brakelight on rear hatch.

Just reading through this topic out of interest but this explains an issue I have. I seem to be getting water in my boot but could not find the source. I will check out the high level brake light! Thanks!!