That was a good video Much more pertinent for motos, whose whole systems are more exposed to the elements than a four-wheeled vehicle, which is already pretty exposed. At least cars have more airflow blocked by bodywork -- and on a typical motorcycle, two distinct and non-linked systems (although today a lot of motos have ABS and/or linked brakes like Hondas, so could be considered a single system. Still directly sprayed with pressurised water every time your wash your bike... Anyhow... takeaways from a pro wrenching past: not only is DOT3 least of the 3 glycol-based fluids to absorb water, it's cheap too... which is why unless litigation makes your mfr's lawyers uneasy... your car will have DOT3 as OEM most sportbikes are DOT4, esp if they're race replicas (sport ATVs too, ex. Honda TRX400EX or Yamaha 660 / 700R Raptors). Any others, DOT3. probably upgraded in the past 20y to 5.1 tho... but tbh I haven't cared since selling my last moto in the 2010s weren't electronic moisture testers back in my day (late '90s - 2010s), and if so, certainly not for $12. Thinking of getting one for the 5G have not seen a single metric motorcycle use DOT5; it's a pretty unpopular fluid in general ime (think Harleys used it for a while). Not sure what genius decided to name it '5.1' rather than '4.1'... but probably results in a population of shadetrees wondering why their '70s muscle-buckets have dragging brakes and a sticking pedal, from bottles of 5 in it (only good thing about 5, is it won't peel your paint off if spilled) almost as if someone designed 5.1 to be used expressly for non-road-legal racecars, knowing the brakes'll get propa-hot, and svc intervals very short and not missed. DOT3's long svc life before needing swapped, is great for those who buy appliances and just put gas in it for 10+ yrs lastly... only swap to 5.1 in your DOT3 / 4 vehicle, if you plan on a) swapping it as often as your moisture sensor says to, which'll be a lot, and b) if you're actually going to get your brakes hot regularly in that interval. Maybe you cross the Rockies on a particularly infamous pass with a steep grade the other side, commuting to work Sure, get 5.1 in your CX-5 and prepare to get dirty (trusting your brakes that many times to a 20-yo fartcan devotee in the local dealer service dept, makes my skin crawl). Otherwise, just a swap to 4 covers just about any sane situation a diligent driver w/ any sense will encounter, and doesn't shorten the svc interval nearly as much. If I didn't need 5.1 dropping down the stair-steps of James Street in Seattle, pounding on my race-prepper SV650 down to get to the ferry terminal 5x a week, humid arsecrack of summer... you won't need it in your RAV4
