W211 estate rear washer not working

[Mbmanman]

W211 estate 2008 Rear washer not working and top up warning on dashboard. Front washers working fine.

Topped up with water and a little Prestone washer additive till full. This did not solve problem.

Looked at the hose in the boot as other posts suggested break. No break.

Subsequently Topped up with neat Prestone and this solved it…

So maybe worth trying this as MB seem to sense concentration of washer fluid and I surmise might default to warning and not supplying water to rear washer

 

[EmilysDad]

..... as MB seem to sense concentration of washer fluid and I surmise might default to warning and not supplying water to rear washer

MB are not that clever More like a blockage that cleared with repeated presses of the washer.

 

[Mbmanman]

Others have posted that MB washer additive is critical

 

[EmilysDad]

Others have posted that MB washer additive is critical

decent screen wash is critical what ever badge is on the car, otherwise you get a build up of sludge on the suction filter where the pump plugs into the bottle. There is no way your car can tell the concentration of screen wash in the bottle. Both screens generally take from the same bottle - pump spins one way for the front & the other for the rear screen. Your front screen washers were working & the rears were not ..... front & rears don't require different concentrations

 

[Mbmanman]

Noted thanks. Obviously the concentration was too low and there must have been sludge/ build up just in rear pipe as neat screen wash appeared to instantly remedy the problem. Thanks

 

[Snake Charmer]

Welcome to the forum. I have an 04 S211 and other than having heated jets front and rear, there is nothing special about the washer system that requires a specific washer fluid.

Prestone has been working well for me over a number of years, very rarely do I see any slime growth in the washer bottles or the dispensing bottle I mix it up in. I do keep the neat and pre-mixed on a shelf out of sunlight so that may be helping.

Some of the vehicles I service at work have all sorts of worrying growths in their washer bottles and hoses. The Triple QX concentrated we have been using from ECP seems to grow lumps in no time if left open in a watering can, horrible!

 

[Chrishazle]

Over the past couple of (rather cold) weeks I've noticed that, on my S204, the front screen washers get back to work quickly whereas the rear can take a while to get back to work. OK, for a while the fluid was at too low concentration for the temperatures - my fault - so I've been topping up with neat and slowly the fronts came back quicker and now the rear. I think it's just that part of the rear pipework and outlet are more in the cold and frost than the front (car parked E-W with the rear to the E). All I've done (apart from topping up with neat every couple of days) is drive the car with the heater set to 24C and try the rear screenwash every few minutes. Once the fluid starts slowly coming through it's not long until it's completely clear.