Aero Engineers - constant back window dirty

[Shadytype]

Hey all.

It seems as though the back window on my 4 runner gets dirty in just a light sprinkle. I just usually wipe it with the wiper and a hold of the rear squirters.

Compare to my wife's X5, it seems that her truck in the same sprinkle stays dry or a lot less wet/dirty.

I know I am going to sound like a nancy, no offense nancy, but whats the reason why the 4runner glass gets so dirty quick on the liftgate?

I put mud flaps on the truck to see if it made a difference, nada. I have a Limited, if that makes a difference.

Is there an aero foil that would potentially prevent or limit this effect?

 

[The_Green_Wang]

When driving the rear creates a vortex causing the dirt to lift and shoot back into the tail gate. Thats what I was told on the forum [emoji854]

Sent from my SM-N950U using Tapatalk

 

[Javin028]

Basically the sudden drop off in the rear creates a low pressure zone that sucks dirt and debris. This isn't exact, but gives you an idea of the airflow:

There's really not much you can do short of a large airfoil to "smooth" out the shape.

Credentials: Am Aerospace Engineer

 

[wcjeep]

My 1988 GMC S15 Jimmy had this problem solved. Odd my 2018 4Runner does not. Doesn't really matter to me. I rarely use the rear view mirror or rear wiper.

 

[MeefZah]

My 1988 GMC S15 Jimmy had this problem solved. Odd my 2018 4Runner does not. Doesn't really matter to me. I rarely use the rear view mirror or rear wiper.

Because the spoiler on those pulls air from the roof line and directs air down over the window; ours does not. I don't mind dirt on the window, what annoys me is dirt getting sucked in when the window is down. Don't ever turn down a dirt road and forget to put it up!

 

[Javin028]

Because the spoiler on those pulls air from the roof line and directs air down over the window; ours does not. I don't mind dirt on the window, what annoys me is dirt getting sucked in when the window is down. Don't ever turn down a dirt road and forget to put it up!

3rd gen 4Runners and a few other SUVs of that era had similar spoilers. I'm assuming they don't really exist anymore since newer vehicles emphasize fuel efficiency, hence the spoiler design on the 5th gens.

 

[TrijiCog]

Ya,that shit really annoys me.....Any bit of water on the road ends up on my rear window on my 2018.

 

[epjfsa]

Ya,that shit really annoys me.....Any bit of water on the road ends up on my rear window on my 2018.

And ironically, unless it's raining hard, it always seems like the rear wiper swipes too often. (This is even having it programmed to the max delay)

 

[Bodhi327]

Haha

This always annoys me but never thought about asking why. I had a third gen and it did not happen. My wife’s old sequoia always got dirty, but if I think about it the sequoia had the same type spoiler as the 5th gen I have now.

 

[Liquid_G]

had this same issue in previous car Subaru Forester. Had the same type of hatch spoiler on it that the t4r has.

 

[johnbt]

I squeegee the rear window when I buy gas. Gives me something to do and does a better job than the wiper.

Work from the top down and remember to wipe the squeegee dry between strokes. Then wipe around the edges to finish it off.

I guess nobody here is old enough to have worked at a full-service gas station. Can I check the oil for you, sir?

 

[tri4cy]

Because the spoiler on those pulls air from the roof line and directs air down over the window; ours does not. I don't mind dirt on the window, what annoys me is dirt getting sucked in when the window is down. Don't ever turn down a dirt road and forget to put it up!

As someone who lives in Iowa and travels on gravel a bit...I have done this WAY too many times. I love opening the sunroof and cracking the rear window. The low pressure created above the sun roof pulls the air in from the back. Also pulls in a crap ton of dust!

 

[rwrobs777]

Occurs to me too on my 2016 and same thing on my 2001 Corvette...always wiping the back down...as far as your 4 Runner...just leave the window down...LOL !!

 

[Tuco Ramirez]

Rustoleum never wet/rain repellent for windows has been my cure for this. Rain X doesn't do it. Always been a rainX or stoners fan but the auto store had the rustoleum stuff on sale. Used it on a Camry I was driving and it made it through rain and snow and lots of highway driving. The back window was nearly spotless.
So I used it on my 4R and it has reduced dirt/dust clinging to near zero. Of course the shit still gets in the area between the weatherstripping and window but the glass itself is clean.

 

[WVhillbilly]

had this same issue in previous car Subaru Forester. Had the same type of hatch spoiler on it that the t4r has.

I used to drive the old square body Sube wagons in the winter.
Had those little aluminum spoilers above the window and they stayed pretty clean.

 

[Inv4drZm]

4th gen FTW.

Less snow and dust with the spoilers.

 

[johnbt]

How long does it take to clean the dried bugs off of that bug deflector?

 

[baldrik78]

Don't ever turn down a dirt road and forget to put it up!

Learned this the hard way, in the first month of ownership. 20 miles of dirt road later, there was a fine particulate covering everything inside.

 

[Sparman]

When driving the rear creates a vortex causing the dirt to lift and shoot back into the tail gate. Thats what I was told on the forum [emoji854]

Sent from my SM-N950U using Tapatalk

That's weird, the forum told me Toyota equips 4runners with an SEU (Silt/Water Ejector Unit, I believe) that sprays the rear hatch with a grime mixture. Apparently it's purely for aesthetic reasons to give the trucks an off-road appearance, and the volume dispensed is proportionately higher based on the model - SR5, TRDOR, TRDORP, TRDP.....

Similar to the urea injection systems on new Diesels, it needs to be serviced (i.e. refilled) by the dealer, otherwise your warranty is voided.

:evil:

 

[mscot]

4th gen FTW.

Less snow and dust with the spoilers.

Yeah. But it looks like a 4th gen...:whip2: