Headlamp washers not working - advice please

[roadvoyager1]

As the title, washers are not working. Apologies in advance this is a long questions.

The diagram below from realoem shows the component parts.

Problem 1 - No water flow in washer pipework.
The pump supplies water to distribution piece 13. I have what seems to be a good flow of water to the inlet to here.
Nozzles 1 and 2 are free running when removed and tested under running water from a tap. When assembled no flow from either nozzle. Pump operates and pressurises pipes prior to piece 13. Straight leg of piece 13 is clear of obstruction when poked with wire.
My initial thoughts:
1. Some obstruction in distribution piece 13, pipe 7, shorter un-numbered pipe feeding nozzle 2 or in valves 5 (x2). Most likely to be valves?
2. Pressure generated by pump is insufficient to overcome internal resistance of system (again valves 5 would seem to be involved).

Problem 2 - Pump not operating as described in manual.
Correct operation is

headlamp washers operate on each 5th operation of the screen washers when lights are switched on. My pump runs first time that screen washers are operated when lights are switched on but do not operate on any subsequent operation of screen washers.
My initial thoughts:
1. My car was built Feb 1999 and has the M52B28TU engine. Is it possible that it also has a later version of software controlling the function headlamp function? Can anybody tell me if the function on facelift models was the same as described in the manual above or was it revised?
2. I have a faulty electrical component in this circuit. Any advice in troubleshooting?

Problem 3 - MOT coming up soon!!
Headlamp washers are included in the MOT test. My understanding is it is only a requirement for them to be tested on cars first used after 1st September 2009, reference section 4.1.6 of 2018 MOT manual, As such my 1999 car should not fail or be given an advisory for this item. Perhaps @t-tony or @Stevo7682 would be kind enough to comment (yes, I know the tester is king in these matters).

Any advice that can be offered would be much appreciated.
​

 

[mrscalex]

They’re quite a rare option so you might struggle a little for specific advice.

I came across them for the first time on my 3.0 Sport project I just put back on the road. But I cheated for now. I repanelled it including non washer front bumper. So I stripped the pipework out, changed the washer reservoir and pretended it was never there. It will go back one day.

Also just picking up another car with headlamp washers on Sunday. So might be better informed then.

In the meantime I would get a helper to operate it. See if the pump works. And then unhook the pipework at the furthest point to each jet in turn (and then both together) to observe behaviour.

 

[t-tony]

The pipe work on my Z4 has quick release connectors in the system and on each washer jet and I'm assuming they're the same on a later Z3.. You can remove/unplug the pipework to blow it through with compressed air. If you operate the pump with the pipe disconnected from the pump itself then you should get a blast of water at high volume rather than pressure. The pressure is simply there to open the spring loaded jets in the bumper and allow water onto the headlights.
Should not be a testable item on your car anyway, or indeed an advisory item.

Tony.

 

[t-tony]

It is possible that the non-return valve (5) is faulty. You should be able to isolate that by removing it temporarily.

Tony.

 

[NZ00Z3]

Is Item 5 a one way valve?
If you disconnect item 5 from item 7, do you get flow?

 

[roadvoyager1]

Thanks for replies so far. To clarify the system fitted to my car comprises a pump and valve (#5) which are common with the contemporary 5 and 7 series models, the surface mounted nozzles are unique to the Z3, hoses and clamps seem to be bin parts.
The pump has good volume output when disconnected from pipework prior to the distribution piece 13. The valve #5 seems to be the main area to investigate. The hoses are held by this type of clamps (@t-tony - unfortunately no quick release fitting). Any tips on getting these clamps off please?

 

[t-tony]

Yes you can put a small flat blade screwdriver between the parts and "flick" them over which releases the clip. You need some "end nippers" to refit these (I used a cheap pair of woodwork pincers and ground the jaws flat across the top) or bin them and use "Jubilee" type clips.
Assuming that the jets are just like larger windscreen washer style jets I'm thinking you must have a blockage somewhere in the system (maybe the non-return valves).Is the filter in the washer bottle clear and clean?

Tony.

 

[Mario]

Hello - I am with the guys that say non return valve - even if the pump looks like it produces good flow it might not have enough pressure to release the valves. Sometimes the washer fluid creates a crud like substance that blocks the filters of the pumps etc. I cleaned the filters on my regular windscreen washer pump and it was like night and day.

 

[Ianmc]

If the pump is working and the nozzles are clear, it has most likely to be a blocked or u/s non return valve. The only time my headlamp washers get used is when the MOT tester checks the windscreen wipers with the car lights on! Likely the less useful extra ever invented.