After a seriously cold night on Sunday, I fired up my FF to defrost the windscreen and generally get it warmed up a bit. After a few minutes the heated screen had cleared the frost and both wind screen washer jets had little thawed patches around them as well, so happily set off on a 50 mile round trip.

About 5 miles later the road was damp and muddy from road works causing the screen to get dirty. I hit the wash button on the end of the wiper control arm and only the passenger side washer dispensed the necessary cleaning fluid. Thankfully there was sufficient splash to allow some effort at keeping the drivers side clear of road gunge.

On getting home, I figured the washer most be frozen so got some warm water and dribbled it over the jet and gave it a minute or two to heat soak, this didn't solve the problem. So stripped out the heated jet and checked that washer fluid was being pumped to it. It was so decided to split the jet and check for blockages. Inside I found a little sprung loaded rubber non return valve. This valve was jamed and twisted into its feed pipe effectively blocking the passage of cleaning fluid. A bit of fiddling later and the valve was freed, jet reassembled and connected back to pipe. Bingo, lots of lovely cleaning fluid at both sides once again.

Conclusion, although filled with proper premixed cleaning fluid (allegedly good for -14c), the fluid in the jet must have frozen and forced the non return valve into the feed pipe. So in future after such chillyness abounds, I recommend checking the washers are both working before setting off of a journey  Should've been old enough to know better...doh!
Current 2010 5.0 SC Autobiography
Previous 2006 TD6 Vogue SE
Previous 1998 P38 4.6 Vogue Autobiography 50 (No 10)

good advice  ... - .- -.




Y. O. L. O.
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I took the non-return valves and springs out of my washers a couple of years ago for the same reason.
I was intending putting a new non-return valve in the pipe supplying the washers in lieu of the washer non-return valves but found my washers worked perfectly well without them even though they shouldn't.
I did nothing more and my washers have worked perfectly ever since.
I've come to the conclusion the washer non-return valves are an un-neccessary complication

Took mine out as well, but the jet is now more of a high volume jet rather than a spray

I has a similar incident last night, defrosted the car went out a few miles later squirted the screen, only LH side working, luckily enough made it to the RH side of the screen, a few minutes later tried again and got both jets,wondered if the heater wasn't working correctly and the warmth of the engine defrosted it, another think to check!