[Aronis]

WOW this thread has turned in to a PSA. Sorry about your car damage. The rest are now forwarded. Perhaps that warning should be on the filler cap?

Mike

[TropicalM]

Originally Posted by USANigel

My washer pumps failed and the dealer says it's because I used orange Rainx washer fluid. I suspect the fluid drained because the seal/pump failed before I added rainx since I apparently emptied the washer fluid reservoir without using it. Has anyone else been told they can only use blue washer fluid?

I had the same problem with my 11 e90 335i. Same thing, started using rainx washer as I like their water repellent. Washer stop working after a while, but I guess it just clogged the system, don't remember details. They fixed it under warranty without hassle. Next Car, e92 M3 always put the BMW blue thing, never had a problem. Makes no sense to me, but decided to keep it safe. I always have a bottle at home in case I get lazy to do the refill at the dealer.

[ZPrime]

I talked to my auto-engineer friend who works for Delphi...

His take on it is that rainX/Aquapel coatings should be fine to use and not a real concern for the sensors. To quote (with some slight clarifications in brackets from me):

RainX is fine. The sensor only detects changes in light in that exact area [above the sensor - the sensor can't "see" the entire windshield in any way] so actually if you RainX the [entire] glass, the sensor won't activate the wipers as much also since it's seeing less refractions on the glass [above the sensor] too.

So if you want to keep the original wiper activation rate, the takeaway would be to not coat the area above the sensor. However, IMO once you have coated the glass, you don't want the wipers to activate as often since the water is just beading up and blowing off anyway... so my feeling is that it's better to just coat everything, and if that makes the wipers run less often, so be it.

I just went back and asked him about why BMW/Audi both would claim that aftermarket fluid could damage the washer system, and this was his reply there:

The RainX leaves a coating on the metal "prongs" of the level sensor. Eventually that coating will get thick enough to prevent any current from passing through so the level sensor will think the tank is empty" since the circuit is now "open" even though the fluid level is fine and should be closing the circuit between the 2 prongs.

So if you care about the fluid warning from the car, don't use RainX fluid. Other cars that use a float-type sensor for the washer bottle wouldn't be affected by this, obviously, but since ze Germans like to use an electronic sensor, there you go.

[msej449]

So first, apologies for an M-Lite intruding on the M2 Forum but this is a topic I've researched, so here we go:

Issue (1) seems to be that mixing BMW and non-BMW screenwash can cause 'gunking' of the system from a viscous residue that forms quite quickly as the result of a chemical reaction. But this doesn't always happen. There's some evidence that completely flushing the BMW solution out, then using something else may be OK. But beware - a BMW service will use the BMW concentrate to top-up, with potential 'gunking' subsequently if you use 3rd.-Party. What you can and can't mix with the BMW stuff isn't clear from Forum postings. The consensus is that 'though this can happen with other models, the 2 Series Coupé, Convertible and M2 seem particularly susceptible.

BMW concentrate can be got in 5 litre containers which is much more convenient and cheaper than five times 1 litre. 5 L is Part Number 83.12.2.298.207 (in the UK, anyway). It's more concentrated than many garage products so apples-for-apples is 'only' about twice the $/pint of third-party products. Reviewing my annual usage, I reckon it's costing me about £13/$16 more a year than cheap stuff. Given a repair to the screenwash system may cost as much as £400/$500 (or more), then I don't think the saving is worth the risk.

As mentioned, the Owner's Manual makes a Really Big Thing of !Warning! a 2 Series owner never to mix BMW and non-BMW washer fluid and always to use the BMW one. So you can't say you haven't been warned. - Yes I know: who reads every section of their OM before they top-up the washer? Especially if you've taken delivery just before the winter weather starts. But it is there. There are a significant number of forum postings along the lines of - Owner: "My screenwash isn't working - seems to be filled with some gunk or something ..." / BMW: "Do you use BMW concentrate?" / Owner: "No, that's just a rip-off. I use stuff from the gas station." / BMW: "Your problem. Read the Owner's Manual. Budget $400+ for us to sort it out."

I agree with the point that the filler cap should have some sort of warning cover. I've made one up myself - it's a 4"x1" plastic label saying only use BMW and make up the solution first before topping-up:

BMW also advise diluting the concentrate before you add it to the reservoir i.e. don't just pour neat concentrate in. As ever, no explanation of why but I can speculate that it may just settle on the bottom and not mix.

Issue (2) There's some confusion cased by what may be an entirely separate problem of algae growing in the screenwash system. Some owners put this down to being in warm climate plus not using the screenwash system much. This means stagnant water in the system and bacterial/algal growth in a nice warm engine compartment. It's hard to determine if these people have used 3rd.-party screenwash or not. A few say they've definitely kept to the BMW blue stuff. My reading is that it's a climate thing but perhaps cheap concentrate is more prone to algae than BMW.

What some owners have done is to flush their screenwash system out just to be sure. You can unplug the tubing near the bonnet jets and then run the washers and collect the liquid - if it looks cloudy/algal/bacterial just flush trough 'till all is clear.

Some people don't believe any of this. Others say they've used 3rd.-party concentrate for years with no problems. So it's hard to really know for sure, other than that the Owner's Manual is so explicit: would they really state this so emphatically just for a little extra revenue from BMW screenwash?. I'll let you decide.