Automotive chemical manufacturer Prestone is currently developing a low-conductivity electric vehicle (EV) coolant that scientists hope can increase EV efficiency.
While ethylene glycol is used in both gas vehicles and EVs, including Teslas, Prestone has increased its research and development budget for learning about less conductive cooling fluids over the past year, as detailed in a report from Automotive News on Friday. Prestone EV Director Tom Corrigan says that that won’t be the case in the future, as the company seeks to develop its own.
“Essentially, EVs are borrowing the internal combustion engine fluid,” Corrigan said. “We are going to see a shift in that in the next one to two years.”
The company has been testing its low-conductivity EV coolants in Ford Mustang Mach-E vehicles at its tech center in Danbury, Connecticut, in recent months. While initial offerings are roughly two years away and will still include ethylene glycol bases, Corrigan also says that petroleum-based dielectric coolants could replace the chemistry in future years.
Coolant types may also be dependent on battery chemistries, with lithium-iron phosphate (LFP), solid-state, and nickel manganese cobalt batteries likely all requiring different coolant makeups. Tesla writes on its website that its cooling systems currently use a phosphate and nitrate-free ethylene glycol-based coolant.
Ethylene glycol can ionize over time when it interacts with metals, plastics, and other necessary engine materials. As the coolant gains electrons, the overall efficiency of a battery-electric vehicle (BEV) is decreased. In addition, the coolant chemistry is expected to shift because of safety, as a BEV-friendly replacement for the corrosion inhibitors used in ICE coolants.
“Those ionize in the fluid and carry an electrical charge. If you have an issue where high-conductivity coolant contacts high-voltage electronics or the battery, it can lead to fire,” Corrigan explains. “So what we are working on is low-conductivity coolant.”
Scientists evaluate the electrical conductivity of coolants using a unit called microsiemens, which measures the conductivity per centimeter. In gas cars, experts expect to see between 3,000 and 5,000 microsiemens per centimeter, considered highly conductive, though it doesn’t negatively interact with gas vehicles in the same way it does for BEVs.
Instead, BEV makers are asking Prestone to develop a coolant with just 100 microsiemens per centimeter, while other fuel cell vehicles may require coolant conductivity levels of just 0.5 to 1.5 microsiemens, according to Corrigan.
“Every bit of increased conductivity is a loss of efficiency in the fuel cell. You’ve got to make the fluid very pure,” he notes.
Along with adding to the company’s R&D budget, Prestone added an additional five scientists and engineers in the department developing coolants for BEVs and fuel cells.
“We see where the future is going with EV coolants, and we want to be ready when the manufacturers are ready,” Corrigan says.
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What are your thoughts? Let me know at zach@teslarati.com, find me on X at @zacharyvisconti, or send us tips at tips@teslarati.com.
News
Tesla Robotaxi Safety Monitor seems to doze off during Bay Area ride
We won’t try to blame the camera person for the incident, because it clearly is not their fault. But it seems somewhat interesting that they did not try to wake the driver up and potentially contact Tesla immediately to alert them of the situation.
A Tesla Robotaxi Safety Monitor appeared to doze off during a ride in the California Bay Area, almost ironically proving the need for autonomous vehicles.
The instance was captured on camera and posted to Reddit in the r/sanfrancisco subreddit by u/ohmichael. They wrote that they have used Tesla’s ride-hailing service in the Bay Area in the past and had pleasant experiences.
However, this one was slightly different. They wrote:
“I took a Tesla Robotaxi in SF just over a week ago. I have used the service a few times before and it has always been great. I actually felt safer than in a regular rideshare.
This time was different. The safety driver literally fell asleep at least three times during the ride. Each time the car’s pay attention safety alert went off and the beeping is what woke him back up.
I reported it through the app to the Robotaxi support team and told them I had videos, but I never got a response.
I held off on posting anything because I wanted to give Tesla a chance to respond privately. It has been more than a week now and this feels like a serious issue for other riders too.
Has anyone else seen this happen?”
My Tesla Robotaxi “safety” driver fell asleep
byu/ohmichael insanfrancisco
The driver eventually woke up after prompts from the vehicle, but it is pretty alarming to see someone like this while they’re ultimately responsible for what happens with the ride.
We won’t try to blame the camera person for the incident, because it clearly is not their fault. But it seems somewhat interesting that they did not try to wake the driver up and potentially contact Tesla immediately to alert them of the situation.
They should have probably left the vehicle immediately.
Tesla’s ride-hailing service in the Bay Area differs from the one that is currently active in Austin, Texas, due to local regulations. In Austin, there is no Safety Monitor in the driver’s seat unless the route requires the highway.
Tesla plans to remove the Safety Monitors in Austin by the end of the year.
Tesla has officially opened Robotaxi access to everyone and everyone, but there is one catch: you have to have an iPhone.
Tesla’s Robotaxi service in Austin and its ride-hailing service in the Bay Area were both officially launched to the public today, giving anyone using the iOS platform the ability to simply download the app and utilize it for a ride in either of those locations.
It has been in operation for several months: it launched in Austin in late June and in the Bay Area about a month later. In Austin, there is nobody in the driver’s seat unless the route takes you on the freeway.
In the Bay Area, there is someone in the driver’s seat at all times.
The platform was initially launched to those who were specifically invited to Austin to try it out.
Tesla confirms Robotaxi is heading to five new cities in the U.S.
Slowly, Tesla launched the platform to more people, hoping to expand the number of rides and get more valuable data on its performance in both regions to help local regulatory agencies relax some of the constraints that were placed on it.
Additionally, Tesla had its own in-house restrictions, like the presence of Safety Monitors in the vehicles. However, CEO Elon Musk has maintained that these monitors were present for safety reasons specifically, but revealed the plan was to remove them by the end of the year.
Now, Tesla is opening up Robotaxi to anyone who wants to try it, as many people reported today that they were able to access the app and immediately fetch a ride if they were in the area.
We also confirmed it ourselves, as it was shown that we could grab a ride in the Bay Area if we wanted to:
🚨 Tesla Robotaxi ride-hailing Service in Austin and the Bay Area has opened up for anyone on iOS
Go download the app and, if you’re in the area, hail a ride from Robotaxi pic.twitter.com/1CgzG0xk1J
— TESLARATI (@Teslarati) November 18, 2025
The launch of a more public Robotaxi network that allows anyone to access it seems to be a serious move of confidence by Tesla, as it is no longer confining the service to influencers who are handpicked by the company.
In the coming weeks, we expect Tesla to then rid these vehicles of the Safety Monitors as Musk predicted. If it can come through on that by the end of the year, the six-month period where Tesla went from launching Robotaxi to enabling driverless rides is incredibly impressive.
News
Tesla analyst sees Full Self-Driving adoption rates skyrocketing: here’s why
“You’ll see increased adoption as people are exposed to it. I’ve been behind the wheel of several of these and the different iterations of FSD, and it is getting better and better. It’s something when people experience it, they will be much more comfortable utilizing FSD and paying for it.”
Tesla analyst Stephen Gengaro of Stifel sees Full Self-Driving adoption rates skyrocketing, and he believes more and more people will commit to paying for the full suite or the subscription service after they try it.
Full Self-Driving is Tesla’s Level 2 advanced driver assistance suite (ADAS), and is one of the most robust on the market. Over time, the suite gets better as the company accumulates data from every mile driven by its fleet of vehicles, which has swelled to over five million cars sold.
The suite features a variety of advanced driving techniques that many others cannot do. It is not your typical Traffic-Aware Cruise Control (TACC) and Lane Keeping ADAS system. Instead, it can handle nearly every possible driving scenario out there.
It still requires the driver to pay attention and ultimately assume responsibility for the vehicle, but their hands are not required to be on the steering wheel.
It is overwhelmingly impressive, and as a personal user of the FSD suite on a daily basis, I have my complaints, but overall, there are very few things it does incorrectly.
Tesla Full Self-Driving (Supervised) v14.1.7 real-world drive and review
Gengaro, who increased his Tesla price target to $508 yesterday, said in an interview with CNBC that adoption rates of FSD will increase over the coming years as more people try it for themselves.
At first, it is tough to feel comfortable with your car literally driving you around. Then, it becomes second nature.
Gengaro said:
“You’ll see increased adoption as people are exposed to it. I’ve been behind the wheel of several of these and the different iterations of FSD, and it is getting better and better. It’s something when people experience it, they will be much more comfortable utilizing FSD and paying for it.”
Tesla Full Self-Driving take rates also have to increase as part of CEO Elon Musk’s recently approved compensation package, as one tranche requires ten million active subscriptions in order to win that portion of the package.
The company also said in the Q3 2025 Earnings Call in October that only 12 percent of the current ownership fleet are paid customers of Full Self-Driving, something the company wants to increase considerably moving forward.
Tesla Robotaxi Safety Monitor seems to doze off during Bay Area ride
Tesla opens Robotaxi access to everyone — but there’s one catch
