I love starting reviews with catchy sentences, but this one might take the cake – “Vape tanks have finally caught up with electric ovens!” Before you hit the back button, let me explain. The Uwell Crown 4 would have been a great sub-ohm tank without any gimmicks or marketing. But it’s also the first-ever tank with – get this – “self-cleaning” technology.


Maybe the New Year’s champagne is still fizzing around my gray matter, but this might be my favorite marketing shtick in a long, long time. We’ll discuss that in a bit. For now, let’s take a quick dive to see what’s up.

Right from the outset, it’s clear Uwell isn’t content to keep its flagship line of tanks within an old design. Gone is the slightly dated 24mm diameter in favor of a more modern 26mm width. While the packaging says “28mm” I assure you it’s not that wide at the base, and only hits that diameter with the bubble glass installed. Still, it’s nice to see Uwell thinking ahead a little more, and not be so comfortable resting on older design.

Speaking of the expanded bubble glass section, it’s hardly an innovation in 2019, but worth mentioning here, since it bumps the Crown 4’s capacity to a solid 6mL. It’s not quite “all day” capacity, but it’s a significant jump into modern sub-ohm vaping for Uwell, and more than enough to keep moderate vapers satisfied for a while.

UWELL Crown 4 Sub-Ohm Tank Review

Visually, the Crown 4 is much more interesting than the pedestrian designs of Crowns past. It’s hardly outlandish or even “bold,” but the Crown 4 has much more adornment than previous entries, all of it nicely machined. Plus, the finish on my blue/green metallic test model is second to none, and looks strikingly mature on any number of today’s mods.


The machining quality extends to the hardware, which is all nicely threaded and polished, with no burrs or rough edges. It’s an annoyance, even today, to find poor-quality machining, and thankfully Uwell’s standards of excellence didn’t take any time off with the Crown 4.

The real beauty of this tank lies under the hood, where a number of design changes are apparent. First, the Pro Flavor Core Optimization System (Pro-FOCS), which supposedly “recycles” the airflow within the tank body through the coil’s core, enhancing flavor density in each puff. Dumb name? Absolutely. And at first, I wasn’t floored (or even aware of) this feature, but as the proprietary coils broke in, it became clear that the airflow works, and that Uwell remains the master of prebuilt vape coil flavor.

Of course, that leads us to the feature we introduced at the outset of this review – the “self-cleaning” technology that sees its coils reabsorbing excess e-liquid within a condensation tank, creating less mess and waste in every fill.

To be completely candid, my BS meter was at an all-time high when reading about this. And not for anything, but I was a little surprised – Uwell has been very buttoned-up about its products, and rarely concedes to flash and hyperbole when describing them. Instead, they let the quality do the talking over the years.

So, I naturally wanted to vape the hell out of the Crown 4 to see if excess juice (from some purposely heavy-handed fills) would find its way out of the airflow chamber instead of this supposed “condensation tank.” Well you know what? It frickin’ works – and works well!

At no point during my two-week testing period did I have any leaks or major condensation. Of course, there were a few clear droplets that can from extended sessions of high-wattage vaping. But I never once had to break out the Bounty to mop up unexpected spillage.


Moreover, taking apart the tank to swap coils and give it a quick cleaning proved effortless, with no random juice pooling to be found. I don’t know if calling this a “technology” is accurate, but the Crown 4 is one of the most leak-proof, clean operating tanks in my collection, and I’m thrilled with the results, no matter what the company wants to call it.

The rest of the Crown 4 design is equally well-done. The quarter-turn top cap is snug, but opens easily for quick refills. And the juice ports are wide enough to handle droppers, tips, funnels, soft-serve ice cream spouts, or virtually any other filling method vapers can think up.

Uwell Crown 4 IV Tank Specs:

  • 26mm Base Diameter
  • 5mL Standard Glass
  • 6mL Bubble Glass Tank
  • Superior Stainless Steel Construction
  • Pyrex Glass Reinforcement
  • Quarter Turn Threaded Top Refill System
  • Uwell Crown 4 Coil Line
  • Double Helix Mesh Coil
  • Self Cleaning Technology
  • Pro-Flavor Optimization Core System
  • Dual Knurled Adjustable Bottom Airflow Control Ring
  • Gold-Plated 510 Connection
  • Detachable Structure
  • Available in Black, Blue, Green, Rainbow, Purple, Stainless Steel

Uwell Crown 4 IV Tank Includes:

  • 1 Uwell Crown 4 Tank
  • 1 Spare Glass Tube
  • 1 0.4ohm Dual SS904L Coil – rated for 60-70W
  • 0.2ohm Dual SS904L Coil – rated for 70-80W
  • 1 Pack of O-Rings
  • 1 User’s Manual
  • 1 Drip Tip Cover

Observations While Vaping

First, let’s address this new Crown 4 coil system, which is pretty damn impressive. While I was hoping for some cross-compatibility with previous tanks, the increased size and circumference made it pretty necessary for Uwell to change things up. The new listing is as follows:

  • 2ohm Dual SS904L Coil – rated for 70-80W
  • 4ohm Dual SS904L Coil – rated for 60-70W
  • 25ohm SS304 UN1 Coil – rated for 55-65W
  • 23ohm FeCrAl UN2 Coil – rated for 60-70W
  • Double Helix Mesh Coil

Yeah, options aren’t going to be a problem here. My test model came with a pair of the dual SS904L coils, rated at 0.2 and 0.4 ohms, respectively. There isn’t much that separates them in the specs, and there’s little that separates them performance-wise either. Thankfully, both performed equally well, with 8-9 day longevity under regular use, and rich, deep flavor throughout the experience.

In looking at this entire list of coil options, you have to wonder why Uwell makes so many different varieties, when the specs are so similar at the end of the day. I try not to overthink it, especially when the coils are so flavorful and potent, but it doesn’t seem like they’re looking to open the Crown 4 to a wider audience, even if this flavor performance just screams for an MTL derivative.

In the near future, I’ll be putting the rest of those coil types to the test, and will update this review if anything noteworthy happens along the way. I’m particularly intrigued by the one Kanthal/FeCrAl option, considering Uwell seems to prefer stainless steel for most of their offerings.

Another observation was the narrow stock drip tip, which certainly helps to concentrate flavor, but does limit vapor production a bit. I imagine most of the Crown enthusiasts out there are flavor-first vapers, but the Crown 4 is a slightly different breed, and perhaps a wider-bore tip might have opened up the doors to new audiences along the way.

Bottom Line

The Uwell Crown 4 is a damn fine way for me to open our 2019 review year. While it might not be as groundbreaking as previous entries were in the grand scheme of the vaping industry, it’s a nice step toward bringing the company’s staunch design a little closer to its competitors. The Crown series has always been about “no nonsense” vaping, but this is a nice half-step toward boosting the series’ appeal to flavor fiends and cloud junkies alike.

While we have 360+ days to decide if the Crown 4 is worthy of a best-of list at the end of the year, this is certainly a flavorful, enjoyable tank with some nifty features to help separate it from competing products. If you’re looking for flavor without the hassle, the Crown 4 is a great sub-ohm tank that we hope will grow into something even better.

Score: A-