A Not Too Costly Lesson

[Benzowner]

Driving on holiday recently and the windscreen washer level light came on. No problem I thought, parked in the harbour car park in Falmouth, called into a local car spares and bought 5 litre of screen wash and filled up the bottle. We then went shopping for about 2 hours............well ok we had lunch no shopping, got back to the car, turned on the ignition and the god damn, washer bottle light was on. Must be a fault, so drove back to the caravan and opened the bonnet, no windscreen washer fluid I then filled up the container with water and watched the level dissappear and saw the water dripping from under the front bumper. I could not see any leaks and was at a loss where the fluid was coming from, when I remembered using the headlight washers the night before. Nothing to loose, gave them a blast and only one was working, gave them another blast and both worked fine, and low and behold, the leak also stopped. Don't know what caused it, but a bit of info for anyone else who may experience simillar problems.

 

[Frenchy]

Hi,

since the HL washers are under the Bottle, there is a "Counter Valve", sorry, don't know exactly how it is called.

But this valve only opens by High Pressure when you activate the Pump, so may be this valve had something inside so it couldn't close properly.

 

[BTB 500]

I have exactly the same problem with my R129:

http://mbclub.co.uk/forums/showthread.php?t=28633

Because of the hosepipe ban I'm keeping a cover on the car and trying to keep it clean and dry ... so I haven't had a chance to give the washers a blast yet. No idea when I'd last have used the headlamp washers ... I assume they only activate when the lights are on (?), and I don't drive it much at night.

 

[BTB 500]

Well I blasted half a reservoir through my headlamp washers on Sunday, and they still leak

Couldn't find the valve in WIS, it's due a service in the next couple of weeks so I may let the dealer sort it out.

 

[stats007]

They do only operate with the lights on - the later R230 has a seperate button for headlamp washers. The check valve only operates for the windscreen washer jets by the look of it. The headlamp jets just have a direct connection to the washer pump according to the diagram.

 

[BTB 500]

That's what I thought, looking at the diagram, but it makes no sense as the windscreen jets are well above the level of the reservoir ... whereas the headlamp ones are well below. So you would expect water to siphon out, without a check valve.

My guess after looking at WIS was that the valve was incorporated in the pump.

 

[stats007]

As you say, either the pump operates as a valve or as Nav said there is another valve not shown on the diagram. Later cars had seperate pumps for the screen / headlamp wipers. Can't be too hard to trace the hoses.

 

[BTB 500]

Later cars had seperate pumps for the screen / headlamp wipers. Can't be too hard to trace the hoses.

The hoses disappear under the o/s headlamp, I will try and have another look though. Don't understand how the headlamp washers only operate when the lights are on, when there's only one pump?!

 

[stats007]

I presume it's linked to the wiper itself? Interesting thought though!

 

[KLP 92]

The hoses disappear under the o/s headlamp, I will try and have another look though. Don't understand how the headlamp washers only operate when the lights are on, when there's only one pump?!

The valve is located underneath the driver's side headlight on the R129. I had my headlights out when i changed it, my passenger side wiper would drip out water continously!

I don't think you can get to it without removing the headlamp. Its about a 10-15 min job, not complicated. On the radiator side of the headlamp is one screw located under a small removable plastic panel. Remove the indicator lense and there should be 2 screws holding the headlamp. There are 2 screws holding the small panel underneath the headlamp, one located in the wing, and one near the radiator end. Remove the wiper and the panel should come out and the headlamp should slide out.

 

[KLP 92]

Just looked on the EPC and couldn't find it on there. I popped into my MB dealership and asked them for the check valve for the headlamp wash wipe. It cost about £7.