windscreen washers blocked
Thread Starter
Newbie
Joined: Mar 2015
Posts: 5
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Ml 350 w166
windscreen washers blocked
I have a 2012 W166 ML350 Bluetec.
The front and back windscreen washers do not work. I can hear the pump.
the Headlight washers works well.
Because both front and back are not working I don't think it is the nozzles.
Is there a check valve in the system that could be clogged.
Does each nozzle have its own check valve.
Will I do any damage by using a needle in the spray jet holes.
Any advice will be welcome.
The front and back windscreen washers do not work. I can hear the pump.
the Headlight washers works well.
Because both front and back are not working I don't think it is the nozzles.
Is there a check valve in the system that could be clogged.
Does each nozzle have its own check valve.
Will I do any damage by using a needle in the spray jet holes.
Any advice will be welcome.
MBWorld Fanatic!
Joined: Mar 2004
Posts: 1,175
Likes: 24
From: Boston, MA
'14 ML350, '13 C220 CDI, '07 C280, '98 ML320
I don't believe there is any check-valve in the windshield water system.
There is a screen/filter that is attached to the pump where the water gets pumped in to the system. It is possible that screen/filter is clogged. There is a separate pump for headlight washer and a separate pump for the windows cleaning.
If I were you, I'd pull out the pump and check the condition of the screen.
There is a screen/filter that is attached to the pump where the water gets pumped in to the system. It is possible that screen/filter is clogged. There is a separate pump for headlight washer and a separate pump for the windows cleaning.
If I were you, I'd pull out the pump and check the condition of the screen.
Thread Starter
Newbie
Joined: Mar 2015
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Ml 350 w166
Washer Problem
Thank you for the info.
The next query would be:
How to get at the pump as it is hidden way down somewhere below the left headlight and water bottle.
On YouTube there are only different and older models and on each they seem to want to pull half the car apart to get at it.
Is there a solution I could use to dissolve any gunk that may have built up without damaging any components (and Paintwork).
The next query would be:
How to get at the pump as it is hidden way down somewhere below the left headlight and water bottle.
On YouTube there are only different and older models and on each they seem to want to pull half the car apart to get at it.
Is there a solution I could use to dissolve any gunk that may have built up without damaging any components (and Paintwork).
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,012
From: Miami, FL
2003 CL 600
Nothing to clean it without removing it.
Pull the wheel and fender liner, you should see it there. Not that bad to get to, take it out, clean the screen or replace it (they are cheap at the dealer), and it will work like new again.
Pull the wheel and fender liner, you should see it there. Not that bad to get to, take it out, clean the screen or replace it (they are cheap at the dealer), and it will work like new again.
MBWorld Fanatic!
Joined: Mar 2004
Posts: 1,175
Likes: 24
From: Boston, MA
'14 ML350, '13 C220 CDI, '07 C280, '98 ML320
^ +1.
Removing the left front wheel helps if this your first time accessing washer fluid pump.
It's not absolutely necessary [to remove the wheel]. What I do is turn the steering all the way to the right so the front wheels are pointing to the right, then remove the pins and screws holding the plastic liner for the front left wheel well - you only need to lift up the liner that is towards the front. You should see the washer tank. These pumps are usually attached to the side of the tank. You just need to pull the pump straight up. Use a screwdriver as leverage, if necessary.
Removing the left front wheel helps if this your first time accessing washer fluid pump.
It's not absolutely necessary [to remove the wheel]. What I do is turn the steering all the way to the right so the front wheels are pointing to the right, then remove the pins and screws holding the plastic liner for the front left wheel well - you only need to lift up the liner that is towards the front. You should see the washer tank. These pumps are usually attached to the side of the tank. You just need to pull the pump straight up. Use a screwdriver as leverage, if necessary.
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fyi, i have a 2016 gle (USA). i have determined that the rear wiper washer feed takeoff from the reservoir is higher than the windshield takeoff. the rear washer stops far ahead of the "check fluid" indicator. this is now consistent since purchase (kept an eye on it). figure more important to see ahead than behind (but i thought that was Italian road-racing rules 
) don't know if any of this pertains, just wanted to provide some info. good luck, ron
) don't know if any of this pertains, just wanted to provide some info. good luck, ron
Thread Starter
Newbie
Joined: Mar 2015
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Ml 350 w166
Washer Problem
Thanks everyone, I will have a go at it with the wheel on. If unsuccessful I will go up to my son-in-law's who has all the good gear including a heavy duty jack and an air compressor. As he likes me so much, I might even get him to wash the car. And, Italian Joe1, I have 2 Alfa Spiders for my own toys. The Merc is for the missus and towing the camper trailer.
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Senior Member
Joined: Jul 2017
Posts: 487
Likes: 114
From: DFW, TX
Ml350 bluetec
Don't matter if fluid is from Walmart or otherwise. My experience with WW fluid is anything that leaves some sort of film that is similar to RainX will cause issues with MB, VW and probably BMW WW systems. The only fluids that work well are your standard WW fluid that just evaporates and does not leave a water repellent film on the windshield.
MBWorld Fanatic!
Joined: Mar 2004
Posts: 5,017
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From: Ft. Lauderdale Area, USA
2015 ML 350
There is a filter in the bottom of the WS Fluid Tank that gets clogged periodically. They have to remove the fender liner to get to it... that is your problem. I primarily use the green bug type fluid (whichever is cheapest) but will substitute the blue when I can't get it.. (Which is an irrelevant fact).
The filter will solve your problem.
The filter will solve your problem.
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
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From: Miami, FL
2003 CL 600
What he's showing is the "filter", it is part of the grommet that the pump sits in. We usually replaced them, you can also rip off the slotted end and it won't plug up in the future. I've never seen a pump actually clog up, only that rubber filter, so I don't know how that will go for everyone but we never saw it be an issue.
Junior Member
Joined: Oct 2009
Posts: 19
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From: CA, USA
Model: ML320 Year: 2000; Model: ML350 Year: 2012
Blocked windscreen washer filter
What he's showing is the "filter", it is part of the grommet that the pump sits in. We usually replaced them, you can also rip off the slotted end and it won't plug up in the future. I've never seen a pump actually clog up, only that rubber filter, so I don't know how that will go for everyone but we never saw it be an issue.
Junior Member
Joined: Aug 2023
Posts: 16
Likes: 1
2012 ML350 Bluetec
Hi all, I recently had my 2012 ML350 Bluetec get clogged on both front and back / I can hear the motor but no fluid comes out. I put rainx green into the compartment before it stopped working.
I took it to a shop and they cleaned the nozzle out for $50 (didn't have to take off tire) following almost exactly what the guy in the below YouTube did.
My question is - should I switch to just plain distilled water going forward or continue to use rainx green now that my wipers are back to working? Or is there another recommended fluid so I don't get clogged again?
https://www.walmart.com/ip/17179629
I took it to a shop and they cleaned the nozzle out for $50 (didn't have to take off tire) following almost exactly what the guy in the below YouTube did.
My question is - should I switch to just plain distilled water going forward or continue to use rainx green now that my wipers are back to working? Or is there another recommended fluid so I don't get clogged again?
https://www.walmart.com/ip/17179629
Last edited by MBUser901; Sep 13, 2024 at 12:18 PM.
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From: In my garage
E55, GLS450, GL63, GLE350
You should be good to go for many years. Just be glad you don't have a 63 as it is a real PIA to clean that rubber filter. You have to remove the front passenger wheel, remove the fender liner, completely unfasten the washer reservoir as it is behind the wheel inside the fender close to the passenger side door, remove the filler neck, and tie it up so it doesn't pull out the seemingly 50 rubber hoses that run all over the car.
