Blocked screen washer

S

shauncoles

Member
I just had my 2009 E89 SDrive23i serviced by a non-specialist and noted before that the screen wash was feeble, barely any liquid hitting the screen. When I got it back they said they tried to clean the nozzles but it didn't improve the flow...
Anyway today I siphoned all the liquid out of the reservoir and found a lot of dark gunk left behind. Never seen that before on any car! So I flushed out with a garden hose. It is still a feeble trickle so is there a filter in line that might be blocked? The pump is on the engine side of the reservoir and looks like it might be removable for disassembly but there not room to get fingers down there. Could I remove the whole reservoir with pump attached to sort this issue. Any suggestions please.
Thanks Shaun in Market Harborough
 
Not sure about the E89, but I've had the same problem with my E86 and E46 in the past.

The washer motors are a push fit in the reservoir, so if you disconnect the electrical connectors and the washer pipes you can remove the reservoir with the pumps still fitted in it. Once you have got it out, wiggle the pump (or pumps if you have headlight washers) and they should pull out. You will find filters on the end that fits inside the reservoir and in both cases mine were gummed up with horrible blue goo!

I cleaned them off with an old toothbrush, flushed the reservoir until it was clean, put it all back and filled up with fresh screenwash - haven't had a problem with either of them since. But I make sure I always top up with the same brand of screenwash - mixing them seems to be one of the causes of the problem.

I found the hardest bit of the job is working out how to get the reservoir out - otherwise it's pretty straight-forward!

Good luck. :thumbsup:
 
Thanks to Mr Tidy plus a two year old response to a similar question by ric19 I sorted it out today in about two hours. Yes basically remove the electrical connectors plus the two water pipe feeds (not easy until I figured out the little blue indents that had to be pushed in with a small screwdriver to release the pipes.) Then I removed the whole reservoir and two motors plus the fluid level gauge. This took the best part of an hour as I didn't want to damage anything and I wasn't certain how everything came apart. The whole of the inside of the reservoir was covered in a browny green slime which took about 15 mins of backwashing using the shower hose in the bath. I didn't realise the two black rubber seals for the two motors had filters that also needed cleaning. Then I flushed it three times with a combo of thin & thick bleach and then backflushed again with the shower hose. The amount of gunge that came out was unbelievable! Connected it all up, refitted it into the engine bay which took 2 minutes and hey presto! Windscreen washers perfick.
So what causes this brown sludge to form? BMW must be using antifreeze washer fluid that is incompatible with other commercial fluids causing a reaction when mixed with these and causing some form of polymer to form. My understanding is that most washer fluid are alcohol based, usually iso-propanol. The Z4 manual only states "Anti-freeze for the washer fluid is highly flammable, keep it away from sparks or flame"
So I just tried to set fire to a small dish of conc. washer fluid with a lighted taper and it just went out! So maybe the Germans have different stuff than we use here?
 
Good post, topped mine up a few weeks back and slowly seen a drop off in pressure. Used a Halfords purchased screenwash, looks like I have a job to do to clean it out and restore the pressure now I know what to do.

:thumbsup:
 
Glad you got it sorted OP. :thumbsup:

I've no idea why the BMW stuff seems to react with any other screenwash, unless of course it is to make owners buy their high-priced product.? :o

But having got mine thoroughly flushed out I've used the cheap stuff I get in Tesco's, and having used nothing else I haven't had a problem!
 
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