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** PERODUA MYVI WATER LEAK INTO CABIN FIX **
CAUSE: MISSING WINDSCREEN SEALANT TO A PILLAR
FIX: REMOVAL AND REFITTING OF WINDSCREEN
Perodua Myvi SXI 1298cc DVVT (model year late 2006 to early 2007) water leak, leaking into driver or off-side floor well, down base of A pillar, over pedals, over electrics by base of door, leading wet carpet, causing damp, mould, mildew and smells.
Leak circumstance: water ingress after heavy rainfall, showing as drips on driver's floor mat, when moving away 100-150ml pour over accelerator pedal. Musty smell in the car on hot days.
Upon stripdown, it was clear that a great deal of water had run down behind and under the lower bulkhead soundproofing matting, under the plastic backed carpet and into the underlay covering the entire offside front floor pan, with the most water accumulating under the driver's right foot area. Water running down right hand side of bulkhead and worryingly over the electrics mounted by the lower hinge area of the driver's door. The problem is masked by the majority of the water falling behind the waterproof backed carpet and being hard to spot in the floorpan, as the only sign of a leak is the small leak over the pedal area on driving away.
After a great deal of exploration, removing the scuttle panel, I discovered absolutely that this is not the normal problem in many cars of a leaking pollen filter or heater intake caused by the drain holes in the plastic intake getting blocked with silt: the Myvi does not have an air intake box with drain holes, just a simple metal shelf under the wiper mech, with a free run off over the top of the inner wings, which is far too big to get blocked; the air intake is also located very high and away from any possibility of flooding.
After painstaking research and some Google translation of the Malay Myvi forums, I uncovered the fact that several late 2006 cars had been subject to warranty claims for windscreen replacement, and other owners had reported leaks identical to mine. The claims were upheld as the machine dispensing the sealant around the windscreen at build stage in the factory seemed to have run out or blocked for an area of three to four inches along the offside or driver's A pillar (windscreen pillar), running upwards from the area that the front wing joins the A-pillar, meaning the seal was incomplete and allowed water in, which dripped down onto the cabin side of the bulkhead.
The problem in the UK is that the Myvi is a rare car and no-one has heard of it, so pattern parts are unheard of and Perodua no longer sells cars in the UK, so finding a screen was going to be tricky if it happened to break upon removal.
Four main glass firms could not source a screen; one finally came up with one for £500+; not one of them would risk removing the screen in case they broke it.
I then spoke to National Windscreens in Hereford who were confident they could remove, reseal and refit the screen without breaking it for £60+ VAT at my home address, and would charge £300 for a new screen if needed.
They came out, removed the screen and without prompting showed me the cause of the leak: an area of three to four inches of minimal sealant running from the wing join up the A-pillar, which would allow water in. New sealant, screen refitted, problem solved 100% in under an hour on my drive. £72 paid inc VAT, delighted it was sorted.
I then totally dried out all areas including the backing of the bulkhead soundproofing, resprayed the rusting surface of the floorpan, cut some waterproof underlay and replaced the damaged underlay/soundproofing, refitted the carpets and fitted the plastic trims. Job done.
This fault apparently affected a few of the early production-run cars from late 2006, and the production was modified after warranty claims highlighted a fault on the sealant application process.
This took me ages to solve, and almost lead to the sale of the beloved Myvi as it appeared unfixable. I hope that posting this saves others the hours of frustration I endured, and gives an easy pointer to achieving a successful fix.