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.
RELATED:
StoreDot closes in on U.S. market entry with launch of R&D campus in California
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.
Tesla just gave what is perhaps its biggest signal yet that the launch of the Cybercab, its autonomous ride-hailing-geared car, is imminent.
The Cybercab has been spotted outside of Gigafactory Texas in massive numbers over the past few days, with hundreds of units being stored on property just days after the vehicle received a Certificate of Conformity from the EPA.
Today, things were a bit different.
Cybercabs spotted on Giga Texas property today had an addition: a Cybercab decal on the side, reminiscent of the “Robotaxi” ones that were placed on Model Ys just as the company launched its ride-sharing platform about a year ago.
Giga Texas drone operator Joe Tegtmeyer noticed the change today:
Tesla Cybercabs are now getting “Cybercab” logos on the side of them!
Tesla did the same with Model Ys that were given “Robotaxi” logos: https://t.co/DanANtw1m7 pic.twitter.com/FqOhH0S9Ks
— TESLARATI (@Teslarati) June 19, 2026
Tesla could be signaling that the Cybercab is preparing to enter the Robotaxi fleet in the coming weeks or months with this move. It seems more symbolic than anything; Tesla is ready to throw Cybercabs in the ride-hailing platform just as it did with Model Ys last year.
The addition of the Certificate of Conformity awarded to the Cybercab is another major factor working to Tesla’s advantage. The company now has permission from the EPA to allow the vehicle to operate on public roads and enter the chain of commerce. It’s officially street legal.
Tesla Cybercab specs revealed: range, curb weight, range ratings, and more
The big question that remains is whether Tesla will be able to operate the car without a safety monitor, especially considering it plans to put the car out there without a steering wheel or pedals. With the Cybercab only having a seating capacity of two, it is hard to believe Tesla will even consider putting a Safety Monitor in the car.
It did recently self-certify as Level 4 and has the ability to operate driverless vehicles in the State of Texas under a law that took effect on May 28. You can read more about that here:
Tesla’s Robotaxi dreams just took a massive step toward reality
We’d imagine Cybercabs will be on the roads as soon as July, but August will likely be a better estimate of when the car will be entered into the Cybercab fleet. It all depends at where Tesla is, as they’ve truly prioritized safety with the rollout of the Robotaxi platform.
Elon Musk has publicly questioned Moody’s credit assessments following the rating agency’s decision to assign SpaceX a Baa1 investment-grade rating, two notches above Tesla’s Baa3. The comments came amid discussions comparing the two companies’ financial profiles.
SpaceX earned its first-time Baa1 rating with a stable outlook from Moody’s. The agency highlighted the company’s leadership in orbital launches, the growing recurring revenue from its Starlink satellite network, strong vertical integration, U.S. government contracts, and emerging opportunities in AI infrastructure.
These factors were cited as supporting robust cash flows, margin expansion, and financial flexibility.
Musk responded directly: “Tesla’s credit rating is ridiculously low tbh,” and added, “Yeah, makes no sense. Tesla has over $40B in cash, no debt, and is consistently profitable!” His remarks underscored Tesla’s balance sheet strength and profitability at a time when many traditional automakers continue to report losses in the shift to electric vehicles.
Yeah, makes no sense.
Tesla has over $40B in cash, no debt and is consistently profitable!
— Elon Musk (@elonmusk) June 19, 2026
Tesla maintains a leading position in the global EV market, with diversification into energy and storage, battery technology, and robotics through projects like Optimus. Recent financial updates show the company generated positive free cash flow of $1.4 billion in Q1 2026, supported by operating cash flow of $3.9 billion. Cash and short-term investments stood at approximately $44.7 billion.
Moody’s has affirmed Tesla’s Baa3 issuer rating with a stable outlook in periodic reviews, acknowledging the company’s EV leadership, technology strengths, including AI for autonomous vehicles, solid profitability, and strong liquidity.
Tesla (TSLA) scores Baa3 Moody’s rating for ‘stable’ outlook
However, the agency has also noted challenges in the automotive segment and expectations for margin pressures.
Musk’s critique highlights a common debate about how traditional rating methodologies apply to high-growth, capital-intensive technology companies. SpaceX benefits from long-term government-backed contracts and diversified, recurring revenue streams, while Tesla’s valuation reflects heavy investment in future technologies such as autonomy and robotics.
Both ratings remain investment-grade, yet the one-notch difference has fueled online discussion about potential inconsistencies in evaluating innovative firms.
The exchange comes as SpaceX explores financing options following its recent valuation milestones, while Tesla continues executing on its multi-year roadmap. Musk’s pointed response serves as a reminder that credit ratings, though influential for borrowing costs, represent one lens through which markets assess corporate strength—and that company leaders often view their financial positions through the lens of long-term innovation and cash generation rather than short-term risk metrics alone.
A new report from Reuters claims that a transport authority in Sweden is pushing back against the approval of Tesla’s Full Self-Driving suite because it will travel over speed limits.
The report says the Swedish Transport Administration (TRV) recommends the European Union votes against FSD’s approval. TRV believes it should not be approved until Tesla disables FSD’s ability to speed.
TRV sent a letter to the European Union’s Technical Committee on Motor Vehicles (TCMV), which is set to meet on June 30 to discuss the potential approval of the Tesla FSD suite in the country. Tesla, which has received various approvals in Europe over the past two months, has not provided a comment.
Teslas operating on FSD do travel over the speed limit, depending on the Speed Profile that is chosen. Drivers have the ability to disengage FSD at any point; Tesla specifically states that those supervising the suite are responsible for its actions.
Let’s cut to the chase: humans operating any vehicle speed almost daily in the United States. Realistically, speed limits in the U.S. are more frequently treated as speed minimums. However, other countries are different, and driving behaviors are less aggressive.
TRV believes that “allowing automated systems to systematically exceed legal speed limits…risks undermining both the legal framework and the expected safety benefits of vehicle automation,” the report stated. It’s surprising that Tesla has not received this claim from other countries previously.
This could be a good argument to bring Max Speed back, the setting that previously allowed the driver to choose the absolute fastest the car would travel.
This would still put the responsibility of supervision in the hands of the driver. It would allow the driver to choose whether the car would travel over the speed limit or not, acknowledging that they set the speed, and if they get pulled over, there would be no ability to argue it.
However, it does not seem as if this is something Tesla will do, especially considering many U.S. drivers have requested the feature in an effort to eliminate speeding or at least tone it down. The company has not shown any interest in bringing it back.
Tesla has approvals for FSD in Europe in Estonia, Lithuania, Denmark, the Netherlands, and Belgium.
Tesla gives its biggest signal yet that Cybercab launch is imminent
Elon Musk challenges Tesla credit rating from Moody’s after SpaceX gets a higher one
