Rear hatch dirt and spray build up

[NvrStk]

Anyone else notice how fast the rear hatch and rear window get completely covered in road grime spray, etc? Could just be that the weather is always terrible here in MN but seems to get coated with grime very quickly even when roads are clear. Has anyone tried mud flaps? Do they help? Any thoughts appreciated.

 

[Pete6114]

I got mud flaps and like them, but they don't do anything to keep the lift gate window clean. Every Suv and crossover we had was like that. Just cant be helped...

 

[Artie]

It’s a major drag having a freashly detailed vehicle pick up grass clipping and storing them on the bumper while driving through your neighborhood. Their needs to be some change to the rear spoiler that directs some airflow off the roof and down the rear. I don’t think this will ever be done because it would cause a .02% reduction in MPG.

yes, it’s very annoying.

 

[armoredsaint]

It’s normal in all SUV, I don’t think it was anymore than our Armada or Escalades

 

[99WhiteC5Coupe]

Same with my 2015 Expedition Limited 4x4.

 

[Gumby]

This is the worst I have seen. It totally sucks.

 

[mhExped]

I also tried mud flaps only to find they don't help with the rear window in any noticeable way.

As far as SUVs go, I can only compare with Ford Flex and Acura MDX. This '18 Expedition is BY FAR worse in this regard.

 

[Lou Hamilton]

My Pilot was just as bad. It just did not show it as much due to the color (Mocha/Beige).

White is bad, but not as bad as a black vehicle.

 

[aggiegrad05]

I also tried mud flaps only to find they don't help with the rear window in any noticeable way.

As far as SUVs go, I can only compare with Ford Flex and Acura MDX. This '18 Expedition is BY FAR worse in this regard.

This is nothing you all don't already know, but...

It's because of the flat back. That's why SUVs have rear wipers and sedans don't. The slipstream in a sedan carries air over the entire length of the vehicle and the dead zone doesn't occur until far beyond the rear window, i.e. behind the trunk. In that dead zone, you get a vortex of slowly swirling air that sucks up any fine mist or grime. The dead zone in a flat-backed SUV happens immediately against the rear window so all that sucked up "stuff" is just deposited on the window. The Expi probably has it a bit worse because of the lip right at the top of the hatch with the CHMSL. That lip will have its own little dead zone immediately underneath it. Were they to remove that lip, it might help but it certainly wouldn't eliminate the issue. The only way to prevent this from happening would be to give the vehicle a tail so the slipstream would be pulled beyond the rear window...which would not be a good look.

Here is a Golf as a stand-in for a flat-backed SUV (I know, I know, it's not an SUV, but it has a flatter back so you can see the effect). Notice the dead zone behind the window. Side note: the Golf does have a rear wiper as a result.



Here is a regular sedan. Notice the dead zone doesn't appear until behind the trunk.

 

[Black]

This is exactly why I swapped to the regular wiper arm on my 2016 so I can just buy the standard 17" wipers and change them frequently. I am on gravel constantly so I just keep a nice stock of wiper blades and fluid.

 

[Donn Brink]

I have the Ford optional rear mud flaps and I would say they help keep the entire back area quite a bit cleaner....

 

[1970Maverick]

This is exactly why I swapped to the regular wiper arm on my 2016 so I can just buy the standard 17" wipers and change them frequently. I am on gravel constantly so I just keep a nice stock of wiper blades and fluid.

What arm did you use to convert your rear wiper?

 

[Black]

What arm did you use to convert your rear wiper?

Dorman 42651 Wiper Arm https://www.amazon.com/dp/B0010DPB00/ref=cm_sw_r_cp_apip_UjlxsM1QMY77Y

Pair it with any standard 17” blade and you are golden.
The arm and a blade are cheaper than the dealer wanted for that stupid rear blade they put on there.

 

[Classic Hauler]

Yes Its Aero Dirtnamics at its finest

 

[Plati]

Dorman 42651 Wiper Arm https://www.amazon.com/dp/B0010DPB00/ref=cm_sw_r_cp_apip_UjlxsM1QMY77Y

Pair it with any standard 17” blade and you are golden.
The arm and a blade are cheaper than the dealer wanted for that stupid rear blade they put on there.

Or buy a Trico that fits the OEM arm for $10 and works fine. That's what I do on my 2014.

 

[Black]

Or buy a Trico that fits the OEM arm for $10 and works fine. That's what I do on my 2014.

Pretty sure 15+ use a different setup than earlier models. This could not find anything other than the OEM style.

 

[sjwhiteley]

As already noted, this happens with all SUVs. I have found it ‘cleaner’ than my old 2009 Chevrolet Suburban.

 

[Shutterbug57]

It’s a major drag having a freashly detailed vehicle pick up grass clipping and storing them on the bumper while driving through your neighborhood. Their needs to be some change to the rear spoiler that directs some airflow off the roof and down the rear. I don’t think this will ever be done because it would cause a .02% reduction in MPG.

yes, it’s very annoying.

The real reason not to do as you say is it would add lift to the rear end. Not a desirable outcome.

 

[stricnine]

I just hose mine down every couple of days, seems to work.

 

[Artie]

The real reason not to do as you say is it would add lift to the rear end. Not a desirable outcome.

A friend of mine had this model Subaru with this factory spoiler, it made a massive difference on the rear deck lid in regards to dirt accumulation. I’m not suggesting anything drastic, nor do I hold any education in aerodynamics so talking out of my ass is a real, and probably frequent, possibility.