Just one sec...
Hey there! Sign in to join this conversationNew here? Join for free

How to diagnose a leak.

Announcements Posted on
Take our short survey, £100 of Amazon vouchers to be won! 23-09-2016
    • Thread Starter


    I have a Corsa C Club 1.0, and in the recent wet weather I've noticed that the footwell of the driver's side rear seat has become totally soaked. I have googled around and it could be one of several things:

    Improperly fitted windscreen (I had mine changed a month ago, might be that, I hope it's that)

    Eroded seal round the brake servo.

    A missing rubber gromit from various lines/pipes running the length of the car

    Blocked pollen filter

    Failed heater Matrix

    I know basically nothing about cars. So what's the cheapest way I can get the problem diagnosed? I don't want to take it to some random garage where the guy is gonna charge 50 quid per half hour and cheekily take 8 hours to find the fault. I've read on the Halfords website that they do diagnostics for free but that seems more based around problems with the engine.

    I'm pretty sure this is gonna cost me an arm and maybe 2 legs. I just need some advice on the best way to go about this.


    A common cause is water running down the side window, past the rubber trim and into the door frame.
    It can then track into the car when the inner seal is broken.

    The seal is found betwen the door frame and inside panel and is usually simply a plastic sheet held in place by the panel and glue.

    It means taking of the inner door handle, winder mechanism etc, then the panel usually 'pops' off.

    But finding and repairing the faulty area is not always obvious.

    A trick can be to driill a hole in the footwell under the carpet, allowing water to drain out.

    But very carefully check underneath for pipes etc first.
    • Thread Starter

    I can pull up the carpet and soak it all up with some towels, so getting rid of the water isn't too much of a problem. Also, I had a friend sit in the back of the car whilst I poured several gallons of water all round the seals, and no water came in at all. So it's not as simple as that unfortunately .. seems to be something underneath or whatever.

    Just need to know what's the best way to actually get it diagnosed, given that it could be one of several things.

    You are halfway there already.
    Identify a possible route of entry.
    Target with a hose pipe.
    Check for ingress.
    Move to next suspect.
    Target must be specfic as liberally spraying water will only confuse
    • Thread Starter

    And if it's coming through the bottom, or through a hole in the block head?

    My bet would be window, door or boot seals. Won't be the heater matrix as that will be under the dash and when they leak it's usually the passenger, driver or both footwell which will be damp.

    The other thing to check is for leaves blocking drains below the windscreen (outside) or at the back of the engine bay.


Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: May 11, 2012
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Which would you rather be...?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22

Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.