Sprinter windshield washer working 1 side only

[seb303]

I'm a little stumped by what should be a simple problem to sort out.

Recently I noticed my windshield washer was only working on 1 side. I disconnected the hose to the non-working side at the non return valve / splitter and blew compressed air through it, checked the nozzles, etc. but no joy. Then I tried swapping the 2 hoses from the non return valve and found that the problem swapped to the other wiper.

So I ordered a new non return valve:

Pardon our interruption...

Have just fitted it and the problem is exactly the same - water only squirts from 1 wiper, and swapping the 2 hoses from the non return valve swaps the problem. Is it possible the brand new, genuine Mercedes part just happens to have the same fault as the old valve, or could there be another problem here?

 

[Droverunner]

In over 45yrs working on hundreds of vehicles I reckon I've only ever had a couple of faulty new parts where the problem remained the same. The first occasion was early in my motoring days and taught me a lesson after hours of wasted time looking for the problem elsewhere... always have it in the back of your mind if the same problem remains it could just be the new part is faulty too.

I would pick up a simple screen wash tubing T-piece from Halfords and substitute that to prove there's not something else going on with the water flow.

 

[seb303]

That's good advice, thank you. I've ordered a cheap Y-piece off ebay (since we live in the middle of nowhere, away from civilisation!)

I guess this will at least test there is sufficient water flow from the pump to feed both nozzles simultaneously...

 

[Droverunner]

If that works you could just get a pair of inline non-return valves from Ebay and fit in the individual wiper feeds. Only £2.99 inc 3-day post for the pair!

Pardon our interruption...

 

[Kev555]

Possibly a worn out washer motor itself and hasn't the power to feed both jets at same time? Does the jets seem strong in the one that is working?

 

[seb303]

Hi Kev,

I've just tried a Y-connector in place of the non-return valve, and now both jets are working, but I would say they are pretty weak. So could well be a worn motor. I haven't yet blown out the hose from the motor to the non-return valve / splitter, so will try this first in case there is a partial blockage lower down.

Do you know if the washer motor just pulls out of the tank? I couldn't see any fixings to undo.

I'm also wondering if it would be bad just to leave the non-return valve out. Presumably this is to stop contaminated water somehow making its way all the way down to the pump. But the pump's on its way out anyway, this could buy me a bit more time before replacing it...

 

[Droverunner]

With poor flow I've nearly always found it to be a kinked pipe somewhere in the run. Re the reason for the non-return I think it's more to stop the water falling all the way back to the pump and a long delay before a squirt arrives at the screen so allowing dry wipers to drag over the screen possibly scratching it.

 

[seb303]

Ah, makes sense about the non-return valve!

I'll also check for kinks when I blow out the lower hose, although not sure how one would have developed in its own (the wipers were working fine quite recently during an MOT test).

 

[EmilysDad]

Poor supply is often down to a blocked suction on the pump. Screen washer pumps are often a push fit into a grommet in the tank which incorporates a strainer of some sort. If no or cheapo screen wash is used, algae builds up & the strainer blocks up with slimes gunge. Remove pump, clean strainer & tank and go from there.

 

[Blobcat]

Poor supply is often down to a blocked suction on the pump. Screen washer pumps are often a push fit into a grommet in the tank which incorporates a strainer of some sort. If no or cheapo screen wash is used, algae builds up & the strainer blocks up with slimes gunge. Remove pump, clean strainer & tank and go from there.

+1

 

[seb303]

Thanks a lot for the helpful replies.

@EmilysDad was spot on - the strainer on the bottom of the rubber grommet was indeed clogged. When I pulled the grommet out of the tank quite a lot of sludge flowed out - the sort of thing you get around the lid of a washing up liquid bottle, which I guess gives a clue what someone may have put in the washer tank in the past!

After cleaning the grommet, the jets are back to full power, and the non-return valve outputs to both sides. Good to note for the future that this particular type of non-return valve will reduce output to 1 side when the flow is insufficient.

 

[Kev555]

windscreen washer additives tend to sludge up left over time especially if too much is added. Water itself coming from a certain type of reservoir can contain algae too