Why does my fast wiper speed seem so slow?
Has anyone else noticed this??

Heavy rain renders them useless.

 

KingRT, I have noticed on my 2012 XJ that the wipers will control their own speed based on how much water landing on the windshield. For example, if you have the wipers on intermittent, if it starts raining harder, they will run non-stop like they were put on slow speed. I seem to recall that I have even seen them go to fast when there was a sudden amount of water that hit the windshield.

So, there is some programming that has gone into the wipers and trying to run them at a speed that is best to keep the windshield as dry as possible without running the wipers full bore.

 

When recently replacing my XJL's wiper blades (Valeo Ultimate OE) from Tire Rack, I also ordered a single treatment of "Aquapel Glass Treatment" a rain repellent (they spell "repellant") which promises to dramatically improve visibility in rain, and which supposedly lasts up to six months.

Developed by Pittsburgh Glass Works, this patented hydrophobic glass treatment, originally developed for the aviation industry, supposedly bonds with glass, unlike others that simply coat the glass, and thus can last up to six times longer.

Being an engineer who appreciates how modifying the wetting angle of fluids attraction to surfaces can cause fluids to bead up rather than adhere to them, I expect this product could dramatically improve vision through through rain soaked windshields far more effectively than increasing wiper speed, which may only cause the wiper blades to "hydroplane" across the whetted windshield (windscreen), rather than "wipe" it dry.

I haven't tried Aquapel yet (we in NC, like much of the U.S., are suffering from the lack of rain), but being a former Boy Scout, I still believe in "being prepared".

I will try to remember to report on the performance of this product under "real world" conditions.

 

Thank for sharing this one. I'm curious to here about your experience. For me, when I have used this type of product in the past, it was great during the day time, but at night, it resulted in lesser visibility because each sweep of the wiper blades briefly left behind a very fine streak of water across the entire contact area - every pass. And to me this made on-coming headlights extremely problematic. The fine beading cleared almost as quickly as it was left behind, but the result with on-coming headlight was, for me, momentarily blinding.

I look forward to hearing more...once it rains for you

 

The difference between the products of days gone by and the new products is the new products don't let the water form a layer. The new products actually cause the water to form a ball on top of the surface. If you do some looking, there are some interesting videos out there. When they do the close ups, you can see the water almost float above the surface. So, if your wipers are going across the surface, you won't have that streaking/super thin layer of water left behind.

But, like you, I am curious how this product will work. I used RainX in the past and while it worked pretty good initially, I found that after time (even after reapplication), things just got horrible and I stopped using it.

 

Thanks for your comments, and I will try to update everyone, once I get the product applied and have a chance to evaluate it in rainy conditions. I never used Rain X, or any other similar product.

Unfortunately, today when I took my XJL into my Jaguar dealer for a four wheel alignment , I was notified that I needed to have both of my lower forward control arms replaced to the tune of $1,400.00 after only 42,860 miles, so I lost the use of my car until I pick it up in the morning. Meanwhile, I'm again driving a 2015 XF; not at all in the same league as a XJL.

Like the Jaguar water pump, needing to replace suspension control arms is a result of premature seal failures. I don't know who Jaguar relies on for providing sealing technology, but whoever it is, internal engineers and/or external automotive suppliers; their technical capabilities are totally inadequate! What a shame.

 

Just an update.

Today I cleaned the XJ's windshield using a product called "Glass Scrub" a stain and grime remover, including water spots, bugs, salt, tree sap and wax (like that applied in brush-less car washes), thus improving windshield wiper performance and visibility, and to provide a super clean surface, to enhance the bonding of the "Aquapel Glass Treatment" I then applied next.

I applied the Aquapel to one-half of the windshield at a time, a practice I would highly recommend, because if you don't remove the product residue thoroughly before it totally dries, it becomes very difficult to remove (similar to paste wax).

So, anyhow, I'm now ready when Mother Nature decides to cooperate and provides adequate rain for a preliminary evaluation, which I'll pass on to you.

 

Finally got some rain, but nothing really intense.

The Aquapel works "as advertised", and, in my opinion, helps the wipers do their job of clearing the windshield of rain. At 50 mph the wind blows off as many rain drops as the wipers wipe off, and I suspect at speeds above 62 mph, (100 kph) you may not need to activate the wipers at all except in a heavy downpour, but this is speculation on my part at this time, as I haven't yet tried it.
The great thing is that this product clears the "non-wiped" portions of the windshield as well the wiped portions. This could be quite significant in cases where road splash contained mud, salt or roar grim.
Regardless, my 17 year old grandson, who gets his driver's license this Friday, was so impressed with the performance of the Aquapel, (which I didn't tell him that I had applied to the windshield) that he wants me to show him how to apply it to the windshield of his sister's Honda that he gets to use while she is away at college.
I think that says it all!

 

Thanks for this first report on product effectiveness. I'm very curious about the streaking and adverse light effects at night with rain as the wipers sweep the window. Good point about the non-wiped areas of glass.

Looking forward to your next update

 

I was finally able to drive my XJL in the rain last night. I didn't notice any streaking or adverse effects from the Aquapel rain repellant windshield treatment, so all is well. At this point I would recommend the product to others.