How to clean Windshield Washer Fluid Reservoir?

[thedriver]

I've got a B7 Passat and recently had a clogged washer jet. Mine are heated so it wasn't a cheap replacement.
Initially I was trying to clean it and noticed the windshield washer fluid reservoir actually had a lot of black gunk stuck to the sides of the reservoir.

Any thoughts on how to clean it?

I can't see anyway to easily remove the reservoir, it looks like hours of work. I tried vinegar and water but it hasn't made any difference. I thought maybe using CLR or something similar and then pumping it through without the jets attached.

Anyone else successfully cleaner their water reservoir?

[Ozsko]

Just a guess, bicarb soda? I would make sure nothing went on the paint work.

[Transporter]

I’d put the garden hose connected to the hot water in and let it overflow/flush for 1/2hour.
If that wouldn’t help then I’d be removing it.

[Amalgam]

Hi,

The black gunk is known as biofilm and is a growth of bacteria/mold in stagnant water that hasn't been treated.

1/ empty or flush out the reservoir of old washer fluid until only fresh water remains.
2/ add Miltons (available at Coles/Woolies baby section. Used to disinfect baby's bottles) to make up a 5% solution and leave until the biofilm is destroyed. 1 hr - overnight.
3/ flush the reservoir out with fresh water
4/ add washer additive to prevent biofilm build up.

BEWARE MILTONS IS A MILD BLEACH

Good luck

[ope126]

Hi,

The black gunk is known as biofilm and is a growth of bacteria/mold in stagnant water that hasn't been treated.

1/ empty or flush out the reservoir of old washer fluid until only fresh water remains.
2/ add Miltons (available at Coles/Woolies baby section. Used to disinfect baby's bottles) to make up a 5% solution and leave until the biofilm is destroyed. 1 hr - overnight.
3/ flush the reservoir out with fresh water
4/ add washer additive to prevent biofilm build up.

BEWARE MILTONS IS A MILD BLEACH

Good luck

Nice write up mate!!!

[thedriver]

Awesome - thanks.

I spoke with someone at VW today and I was given a price of about two hours labour and ~$140 for a new reservoir. It's probably cheaper to replace it if your pulling it out than spend time to try and clean it.
I also spoke with a mechanic that had experience with these in Mercedes and he said they sometimes used an ultrasonic cleaner... interesting idea.

I'll try the Miltons and the hot water and report back - thanks.

[ian]

Like all mold it is easily treated with Bleach , Fill the reservoir with clean water add a full cup of bleach ,within 24 hours the mold will of disappeared, Flush and refill

[Amalgam]

I'll try the Miltons and the hot water and report back - thanks.

Just use room temp water as hot water will accelerate the decomposition of the Miltons.

George

[thedriver]

sorry, I meant I'd use them both separately. Thanks for clarifying though.

[thedriver]

TLDR: For removal of biofilms, my current research suggests using Chlorine Dioxide, not anything else listed in this thread so far.

The black gunk is known as biofilm and is a growth of bacteria/mold in stagnant water that hasn't been treated.
2/ add Miltons (available at Coles/Woolies baby section... make up a 5% solution and leave until the biofilm is destroyed. 1 hr - overnight

So I've had some success (I think) cleaning out the washer fluid bottle, but it's hard to be sure because I can't easily access it to check. And, after some further research it turns out that Miltons may not be the right choice, which is kind of what I experienced as well.

I called Miltons first and asked them about their product, but they had no idea, the person was clueless. The person wasn't technical at all and didn't seem to understand that killing bacteria is not the same as dissolving it into the solution (e.g. physical removal of it from the walls).

Anyway, I used the Miltons at Amalgams recommended rate of 5% (maybe even a little stronger) and let it sit for about 6 hours.
I had to pump out the water first, so I removed the spray nozzles from the tubes and popped the tubes onto the edge of the bonnet so the would pump straight up into the air when the bonnet was closed. This way I could close the bonnet to allow the pump to activate and at the same time spray extra water onto the bonnet so the solution was further diluted as it hit the car.

After fully emptying the reservoir (about 3-4 mins of constant on off ), I checked the washer fluid bottle and could see the biofilm hadn't been removed. It was still there, it had just been bleached. Maybe some if had been removed, but it was impossible to tell and there was obviously still a lot of it.

I sprayed water into it using the Jet setting on my hose nozzle and that disrupted it, more so than before using the Miltons, so the Miltons at least seemed to make it easier to remove. After filling the bottle and pumping it out again I could see bits of stuff coming out through the tubes.
I repeated this flushing about 6 or seven times (partly because I was going to add another chemical and didn't want their to be any reaction).

Seeing how much biofilm was still attached to the bottle after using the Miltons, I didn't feel like I could trust that it was clean in the main part of the bottle where I couldn't see. So I thought I'd try some CLR. I called them and they said absolutely I could use it, but use it at half the ratio that is suggested on the bottle first. If that didn't work, try it at the recommended ratio (1:1).

I tried the CLR and more crap came out, but I still couldn't be sure it was actually clean at the main part of the reservoir. Again I flushed it probably 5 or 6 times to be sure I wasn't spraying any CLR onto my car later.

I found this link last night about Biofilms though: Biofilm removal and control - Lenntech
Interestingly, they note that hypochlorite has little effect on biofilms... And guess what the Miltons is made of?
The Miltons Liquid Solution is Sodium Hypochlorite (the Miltons Tablets are Sodium Dichloroisocyanurate).
So I'm assuming that's why I didn't see any actual removal effect of the biofilm using the Miltons.

That link notes that "it has been proven beyond doubt that chlorine dioxide removes biofilm from water systems." I also found this link that noted "chlorine dioxide disinfection appears to be more applicative to maintain a biological stable drinking water."

CLR is made of Lactic Acid and Lauramine Oxide. So that also doesn't fit with the Chlorine Dioxide requirement. So now I'm on the hunt for some chlorine dioxide to try as a last attempt to really get this puppy clean.

[Transporter]

You could have just drain it with a 1.5m clear flexible tubing and then fill up with very hot water and vinegar let it sit and suck it out again. Most bacterias don’t like heat. After that just use the windscreen washer every time you drive to clean your windscreen, people who do that don’t have bacteria and smelly water in the windscreen washer container.

[Amalgam]

After fully emptying the reservoir (about 3-4 mins of constant on off ), I checked the washer fluid bottle and could see the biofilm hadn't been removed. It was still there, it had just been bleached. Maybe some if had been removed, but it was impossible to tell and there was obviously still a lot of it.

I sprayed water into it using the Jet setting on my hose nozzle and that disrupted it, more so than before using the Miltons, so the Miltons at least seemed to make it easier to remove. After filling the bottle and pumping it out again I could see bits of stuff coming out through the tubes.
I repeated this flushing about 6 or seven times (partly because I was going to add another chemical and didn't want their to be any reaction).

The treatment is working. It sounds like you have very heavy biofilm and multiple treatments are required.


Just a point of clarification from my original post

1/ Miltons denatures biofilm (kills it). It does not dissolve it. For heavy growth, the biofilm may fall to the bottom of the container as semi clear slime. For very heavy growth you need loosen the denatured biofilm before rinsing it off.

2/ Miltons is corrosive at higher concentrations. 5% is a very low dose. I didn't want to damage a forum members car/paintwork etc. You can increase the concentration for faster results, being aware that it is a bleach.

3/ For very heavy deposits multiple overnight treatments may be required.

4/ Yes there are many other treatments available but Miltons is easily available to the general public, safe to use, and less likely to damage your car. Chlorine dioxide is a gas at room temperature . https://pubchem.ncbi.nlm.nih.gov/com...de#section=Top

5/ At work, we use Miltons to disinfect our water lines weekly at a 10% concentration and hyper dose at 50%. Once again our equipment is resistant to Miltons. Your metal water pumps and paintwork are not. It would be safer to put a hose into the reservoir to flush out the solution and slime rather than pump it out through the jets.

6/ This is a "off label" use of Miltons and the representative would either have no idea of treating biofilm or afraid to recommend it. It is used to disinfect baby's bottles and they routinely take calls from new mothers.

I hope this clears up a few points and fills in the gaps.

Bests

George

[thedriver]

fill it up very hot water and vinegar

All great ideas, but I had been through this.

I tried vinegar first (see my OP)... it didn't work. Just made me want chips everytime I used the washers.
The vinegar kills the mould, but it doesn't actually remove any of the crap (biofilm) from the sides of the bottle. My main concern was about this biofilm clogging up my spray nozzles. So I needed a way to actually clean the washer fluid bottle. Because of the shape of the bottle, there's no way to use any type of brush effectively. And there's no easy way to remove it without taking off the front bumper and headlight.

And because of the awkward shape of the washer fluid reservoir, the flexible tubing wouldn't have worked either. My only options are to either dump a hose into the reservoir and try to flood it out, or pump it through the lines (which I figured would perhaps help clear them of any biofil too).

I'm ordering some Cl02 and will see how that goes.

[thedriver]

The treatment is working. It sounds like you have very heavy biofilm and multiple treatments are required.


Just a point of clarification from my original post

1/ Miltons denatures biofilm (kills it). It does not dissolve it. For heavy growth, the biofilm may fall to the bottom of the container as semi clear slime. For very heavy growth you need loosen the denatured biofilm before rinsing it off.

2/ Miltons is corrosive at higher concentrations. 5% is a very low dose. I didn't want to damage a forum members car/paintwork etc. You can increase the concentration for faster results, being aware that it is a bleach.

3/ For very heavy deposits multiple overnight treatments may be required.

4/ Yes there are many other treatments available but Miltons is easily available to the general public, safe to use, and less likely to damage your car. Chlorine dioxide is a gas at room temperature . https://pubchem.ncbi.nlm.nih.gov/com...de#section=Top

5/ At work, we use Miltons to disinfect our water lines weekly at a 10% concentration and hyper dose at 50%. Once again our equipment is resistant to Miltons. Your metal water pumps and paintwork are not. It would be safer to put a hose into the reservoir to flush out the solution and slime rather than pump it out through the jets.

6/ This is a "off label" use of Miltons and the representative would either have no idea of treating biofilm or afraid to recommend it. It is used to disinfect baby's bottles and they routinely take calls from new mothers.

I hope this clears up a few points and fills in the gaps.
Bests
George

Cheers George, much appreciated.

I realise it's off label, but I expect some expertise.

I'm still dubious about Miltons ability to actually removed the biofilm, which is what I need to ensure it doesn't clog the spray nozzles.
I would expect some parents would be concerned about the safety of ingestion and would expect some technical expertise and understanding of the science. Unfortunately, they didn't have that at all. When I asked them if it removes the biofilm, they told me it "Yes, it will kill it." I responded by saying I understand it will kill it but will it actually remove it, to which she replied, "Yes, it kills it, so it's not there any more." I tried other ways of asking the question too; trying to explain that killing something is not the same as removing it, asking her if it would dissolve the biofilm or make it fall off. She just kept on with the "it's dead so it's gone" theory ... I didn't want to use the analogy of killing her but leaving her body to rot in the call centre.

I tried to use your recommended rate, it just might have been marginally stronger because of minor measuring errors.

I don't know what a heavy biofilm looks like. It certainly wasn't covering the whole plastic. Unfortunately, there's no way for me to loosen it with any type of manual agitation; it's too difficult to access.

Whilst it's a gas at room temperature, it can be easily made and is highly soluble in water. I've ordered some Cl02 and will report back.

[Transporter]

All great ideas, but I had been through this.

I tried vinegar first (see my OP)... it didn't work. Just made me want chips everytime I used the washers.
The vinegar kills the mould, but it doesn't actually remove any of the crap (biofilm) from the sides of the bottle. My main concern was about this biofilm clogging up my spray nozzles. So I needed a way to actually clean the washer fluid bottle. Because of the shape of the bottle, there's no way to use any type of brush effectively. And there's no easy way to remove it without taking off the front bumper and headlight.

And because of the awkward shape of the washer fluid reservoir, the flexible tubing wouldn't have worked either. My only options are to either dump a hose into the reservoir and try to flood it out, or pump it through the lines (which I figured would perhaps help clear them of any biofil too).

I'm ordering some Cl02 and will see how that goes.

Any kind of film on the inside is best mechanically removed with a very coarse sand, 1/2L or so of water and shake the bottle with the openings blocked of with hand and rags. It works every time for me on slugged up cooling system reservoirs.