Delay when using screen wash

[molgrips]

Anyone else have to wait a second or two for screen wash to come out? It means that the wipers start to smear any dirt on the screen. Seems like fluid is draining back into the tank between uses. Either the non return valve has failed or there was never one fitted. Does your car do this? The OEM part is the entire hose, so I don't know if I want to go with that or just splice in a generic non return valve.

The car is a 2013 CLS

 

[Petrol Pete]

All should have a non return valve , but I have commented on here before how my MB is the only car (out of 3) that I own and is (from memory) the only car I have had where the wipers start moving as soon as wash wipe is demanded . All others spray and then a second or so later the blades move.

It's annoying and does the wiper blades no favours on a dry and dusty screen.

 

[molgrips]

From memory, it squirts immediately at the second time of asking as if the fluid has not had time to drain back; but I should check. But yes, the fact there is no delay is a poor design regardless of draining back or not.

 

[DSM10000]

When this happened on both of my Mercedes cars I just bought a non return valve from Halfords and placed it in the pipework.

 

[slade1]

Same with 05 CLK. Thought of fitting non return valve but has heating element inside the hose.

 

[DSM10000]

Same with 05 CLK. Thought of fitting non return valve but has heating element inside the hose.

You can still fit one at the outlet end with a small extension pipe

 

[MSG2004]

I've had MB's for just over 20 years and the current one I've had for years is the only one I can relate your concerns to. The gle, on a cold start, if I use the wippers and screen wash within seconds, there is a 2/3 second delay always. Once the car has been running for more than a minute or so, the screenwash and wipers operate within a split second and IIRC, the water comes out first and definitely so on the rear screen

 

[molgrips]

Is the whole pipe heated? On which end did you fit the valve? In terms of backflow it won't matter.