New Member with a dirty rear window
 

Hi All:
I am the proud owner of a new 2011 X5 35d Premium package here in Vancouver and am very happy to find the active member's site. I notice that the rear window quickly gets covered in dirt and grime from wet and slushy roads and the poor rear windshield wiper struggles to keep up.

It looks like the culprit is the rear window spoiler creating a vacuum that sucks up all the sludge and grime which promptly deposits itself on the rear window and upper rear brake lights.

Has anyone experimented with deflectors on the rear window spoiler to create turbulence that would minimize the low pressure/vacuum behind the vehicle? I don't think it would take too much - kind of like the deflectors on aircraft wings to eliminate vortexes.

As I don't ever speed (;)) I am not too concerned about any instability this might cause!

Failing this are there any other solutions that work?

All he best

Joe

Washing

Welcome Horseshoe.
You can't keep your baby clean forever, eh? It is an AWD after all eh? (jk)
Even in Houston I still have to wipe down the rear window several times between fueling because the damn thing keeps getting 500+ miles between fill ups.You could also keep a cheapo squeegee(sp) brush to make sure the back glass stays clean.

Any vehicle with a bluff rear end will have a low pressure area there that causes a dirty rear window. It isn't caused by the BMW spoiler. Manufacturers have played around with top and side spoilers since the 1960s, and they work to a small degree, but there isn't a fix for it. And I think that additional spoilers would look really silly.

As a fellow Lower Mainland driver, the secret is to set the wiper to clean it often enough that there isn't a lot of dirt on it that may scratch the glass. Set the interval to whatever is appropriate for the current level of rainfall and road spray. The wiper can definitely keep up if the interval is reduced. I use the rear wiper enough that I replace the rear wiper blade as the same time as the front blades.

Thanks JCL
Thanks for the feedback. I agree that making modifications to the top spoiler is probably not going to work. However, I am a tinkerer and will see if improvements can be obtained with small modifications. If results show an improvement I'll post.

I have been using the intermittent wiper with limited success. Most times I wind up with a clean semicircle surrounded with sludge.
I have used Rain-X which helps a little but not to the extent I was hoping.

All the best!

Thanks Bluetec!
I lived in Kingwood for 8 years and remember the frequency and intensity of the rain that y'all have - good for keeping everything clean. Up here the issue is road salt and dirt in the winter that doesn't wash off until the spring rains.

Good suggestion on the squeegee as up here I'm getting about 800 km between fill ups!

All the best!

What about mudflaps. Those surely need to have an effect on how much grime gets kicked back.. I dont use them so I wouldn't know. But someone else with experience may know..

Actually there is, but it's not very good looking or aerodynamic. In college I had an AMC gremlin which was one of the first vehicles with the near vertical rear window shape. It collected dust terribly until I bought the accessory which was a "wing-like" type of spoiler which directed air from the roof downwards over the rear window. It worked quite well in keeping the rear glass clean.

http://amc-gremlin.com/wp-content/up...-blue-back.jpg


http://farm4.static.flickr.com/3531/...65f26cc8_o.jpg

I don't think mud flaps work. Our X5 is coated with dirt running down the tailgate from washing the rear window so often. It has been dirty with and without the mud flaps.

That is similar to the rear window deflectors Ford started installing from the factory around 1968 or 1969. We had them on Torinos and LTD Country Squires. They worked better than the old side deflectors, but not perfectly. This wasn't one of ours, but it sure looks similar.