Vellum Venom: What is DLO FAIL?

Sajeev Mehta
by Sajeev Mehta
vellum venom what is dlo fail

Having previously discussed Day Light Opening (DLO), let’s define DLO FAIL.

And perhaps learn why DLOs sometimes fail?

Simply stated, DLO FAIL is when a design team’s Day Light Opening won’t make production, resulting in replacing glass with plastic “cheater” panels. Therefore, in internet-speak, the DLO truly FAILS.

DLO FAIL usually gives the appearance of a sleeker DLO without resorting to expensive glass. But that’s not the only mission.

The F-150 regular cab (above) implements DLO FAIL to integrate a single door design against multiple body configurations. It wasn’t implemented until the 12th-generation.

The 11th-generation regular cab has glass in the B-pillar, except it’s actually a rear-hinged door. Great idea for truck buyers, right?


The designers went too far, making a regular cab more like a pricier super cab. Which goes against the grain of this machine’s mission as the value-packed workhorse, where frills are frowned upon by price-sensitive fleet buyers and thrifty consumers. Or beancounters looking out for the company’s bottom line.

The smarter route was the 10th-generation’s regular cab door, significantly different from the crew cab’s front door. Plenty of precedent, too: Ford turned the four-door 1990 Ford Explorer into the two-door 1993 Ford Ranger with this trick, albeit with more concealing effort. Trucks were predominately two-door before this: quad-door variants were usually limited-production, oddly crafted afterthoughts from the B-pillar back.

But let’s not hammer only on the high volume, multi-cab configuration truck. Even buyers of a fully loaded ($154,000) Tesla Model X get DLO FAIL in the A-pillar as standard equipment.

The company’s concept SUV had a fantastic DLO; too bad even a niche builder gets it wrong sometimes.

So what’s the point? Remember there’s no excuse for DLO FAIL at either end. The Nissan Versa/Tiida or the Ford Fiesta prove that affordable models deserve real DLOs.

And if those are too expensive, perhaps the €5,900 Dacia/Renault Logan shows how not to FAIL on a budget.

Speaking of, what’s the budget to badge engineer the Mercedes GLA 250 into an Infiniti? Doing it with the brand-appropriate “E” shaped quarter window?

Compare the two side-by- side and Infiniti clearly spent some coin so the QX30 sported unique C-pillar skin and rear doors. But there’s no space for their stylized “E” quarter window, so they punted: opting for DLO FAIL.

What a shame, yet it proves there’s many reasons why DLO FAIL makes production. Even if none of them are especially palatable.

[Images: Ford, Tesla, Nissan, and Sajeev Mehta]

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  • MaintenanceCosts Despite my hostile comments above I really can't wait to see a video of one of these at the strip. A production car running mid-eights is just bats. I just hope that at least one owner lets it happen, rather than offloading the car from the trailer straight into a helium-filled bag that goes into a dark secured warehouse until Barrett-Jackson 2056.
  • Schurkey Decades later, I'm still peeved that Honda failed to recall and repair the seat belts in my '80 Civic. Well-known issue with the retractors failing to retract.Honda cut a deal with the NHTSA at that time, to put a "lifetime warranty" on FUTURE seat belts, in return for not having to deal with the existing problems.Dirtbags all around. Customers screwed, corporation and Government moves on.
  • Bullnuke An acquaintance of mine 50+ years ago who was attending MIT (until General Hershey's folks sent him his "Greetings" letter) converted an Austin Mini from its staid 4 cylinder to an electric motored fuel cell vehicle. It was done as a project during his progression toward a Master Degree in Electrical Engineering. He told me it worked pretty well but wasn't something to use as a daily driver given the technology and availability of suitable components of the time. Fueling LH2 and LOX was somewhat problematic. Upon completion he removed his fuel cell and equipment and, for another project, reinstalled the 4 banger but reassembled it without mechanical fasteners using an experimental epoxy adhesive instead which, he said, worked much better and was a daily driver...for awhile. He went on to be an enlisted Reactor Operator on a submarine for a few years.
  • Ajla $100k is walking around money but this is almost certainly the last Dodge V8 vehicle and it's likely to be the most powerful factory-installed and warrantied pushrod engine ever. So there is some historical applicability to things even if you have an otherwise low opinion of the Challenger.And, like I said up thread, if you still hate it will be gone soon anyway.
  • Carlson Fan GM completely blew the marketing of the Volt. The commercials were terrible. You'd swear they told the advertising company to come up with an ad that would make sure no one went out and shopped a Volt after seeing it!...........LOL My buddy asked why I bought a car that only goes 40 miles on a charge? That pretty much sums up how confusing and uninformative the advertising was.