My windscreen washers are partially blocked

[Valve Bounce]

Over a period of time, my windscreen washers have been getting weaker and weaker, and now my driver side washer is just dribbling, although the passenger side washer is working better.

What is the best way to clear the ducts?

[NMMotorsport]

You sure of a blockage? Have you looked at the pump in the washer bottle. Sometimes they have a gauze style filter on them.

[Valve Bounce]

I'm pretty sure its a blockage. However, I had put some detergent into the wather and maybe I put too much because there is a lot of bubbly suds coming out of the driver side. I have got it working a bit, and a some black stuff has come out of the nozzle.

[Eki]

Try blowing pressurized air through the hoses. Or use detergent until all black stuff has come out.

[D-Type]

It's a long time ago but this is what I remember

(1) Try clearing the nozzles with a needle. Sometimes in hard water areas you get a build up of chalk
(2) If that doesn't work you have to progressively clear the pipes. This depends on what you can get to. Sometimes there's a non return valve so you have to do it by stages and always blow towards the nozzle and disconnect the downstream end.(3) Disconnect at the nozzle and at the pump and blow through the pipes (airline or lungs)
(3) Remove the reservoir and flush out all the sludge
(4) Clean the filter in the reservoir.

Other problems:
different detergents can react with each other and form a sludge
Detergent and hard water can form a sludge
Algae can grow in the reservoir forming black sludge - bleach will kill it.

Hope this helps

[Valve Bounce]

It's a long time ago but this is what I remember

(1) Try clearing the nozzles with a needle. Sometimes in hard water areas you get a build up of chalk
(2) If that doesn't work you have to progressively clear the pipes. This depends on what you can get to. Sometimes there's a non return valve so you have to do it by stages and always blow towards the nozzle and disconnect the downstream end.(3) Disconnect at the nozzle and at the pump and blow through the pipes (airline or lungs)
(3) Remove the reservoir and flush out all the sludge
(4) Clean the filter in the reservoir.

Other problems:
different detergents can react with each other and form a sludge
Detergent and hard water can form a sludge
Algae can grow in the reservoir forming black sludge - bleach will kill it.

Hope this helps

I have tried 1.
The pipes have a fork between the driver's and passenger's side nozzles, and the passenger side nozzle works. Also the headlight wiper nozzles work. (Yeah! my Cross Country has headlight wipers)
I don't think that I can remove the reservoir without buggering everything up.
At the moment, I suspect that the short length of pipe to the driver side nozzle may still have some sludge blocking it.

BUT, thanks for your analysis because the fault may be in some combination of what you are stating.

The question here is whether bleach will affect the metallic paintwork of my car.

[Valve Bounce]

Try blowing pressurized air through the hoses. Or use detergent until all black stuff has come out.

I think the excessive detergent concentrate I put into the reservoir may have caused the water to bubble too much and cause some airlock in the pump.
I will ask my wife to come along to the gas station tomorrow and operate the washer while I apply some pressure to the reservoir through the filler.

I will try to clean out as much of the existing water from the reservoir.

How about baking soda (Sodium bicarbonate?) will that clean out the pipes without affecting the metallic paint?

[Valve Bounce]

You can try any of the other suggested methods, but I'd stay away from this one. Chance of damaging the paint is good.

Sounds like you just need to blow out the one side. The rest is functioning normally.

I have been thinking about this while I was having my shower, and I think there may be an airlock somewhere in the system caused by my using concentrated detergent.

[schmenke]

I have never heard of blocked washer fluid lines. Valve, do fill the reservoir with water?

[Valve Bounce]

Yes!