What is the reason for Volvo displaying low coolant when braking?
4 Answers
Volvo displays low coolant when braking because: when the brake is pressed, the coolant will swing back and forth, and if the coolant level is slightly low, it will drop below the standard position, triggering a vehicle alert. Taking the 2021 Volvo S90 as an example, it belongs to the mid-to-large-sized car category, with body dimensions of: length 5090mm, width 1879mm, height 1450mm, wheelbase 3061mm, and a fuel tank capacity of 55L. The 2021 Volvo S90 features a double-wishbone independent front suspension and a multi-link independent rear suspension. It is equipped with a 2.0L turbocharged engine, delivering a maximum horsepower of 250PS, maximum power of 184kW, and maximum torque of 350Nm, paired with an 8-speed automatic transmission.
I noticed my Volvo keeps popping up a 'low coolant' warning whenever I hit the brakes, which is quite odd. As a driver with over 30 years of experience, I suspect a few possible causes: First, there might be an actual coolant leak, such as from an aging radiator or cracked hoses. When the fluid level drops to a critical point, the car's movement during braking makes it easier for the sensor to detect the abnormality. Second, it could be an electrical issue—older Volvos sometimes have faulty circuit boards, and the current fluctuation when braking might interfere with the coolant sensor's signal. Third, the cooling system itself could have buildup or blockages; it might function normally during regular driving, but increased engine load during hard braking causes temperature fluctuations that trigger the warning. I recommend pulling over immediately to check the coolant level. If it's low, top it up with the same type of antifreeze, and schedule a professional inspection to identify leaks or electrical faults. Don’t delay too long, or you risk engine overheating and severe damage.
As a new car owner, my Volvo has been driven for less than a year, and every time I step on the brake, the low coolant warning pops up, which makes me a bit nervous. Possible causes include the coolant level being genuinely low, as I usually don't pay attention to checking it, causing the car to display a warning when braking due to vibration; or it could be a sensor false alarm, as I've heard modern car electronic systems are overly sensitive, and braking actions can interfere with the signals; another possibility is loose cooling system pipes, where leaks may expand during deceleration. I tried opening the hood to check the coolant reservoir's scale line myself—it's located in the transparent container at the front left of the engine. If the fluid level is below the minimum line, it needs to be topped up. If no leaks are found, it's best to visit the 4S shop to scan for computer fault codes—never tamper with it yourself, safety first. This issue is quite annoying, but I learned a trick from online videos: regularly check the coolant color visually—pink indicates it's normal, while brown means trouble.
Having repaired cars for over 20 years, I've encountered many Volvo owners complaining about the coolant low warning flashing when braking. There are several common factors: the sensor's awkward position makes it prone to false alarms due to vibration during braking; the coolant level drops too quickly, possibly due to a minor radiator leak or unsealed connections; or it could be a software glitch in the vehicle's computer, especially in newer hybrid models where braking activates the regenerative braking system, interfering with the coolant monitoring circuit. I recommend first unplugging the coolant sensor connector to clean any oxide buildup at the interface—if the warning stops, it indicates an electronic issue. If not, check if the coolant tank pressure is dropping; use a UV light to easily spot leaks by tracing water marks. It's best not to delay—try replacing a new fuse to prevent the entire system from locking up and damaging the engine. Addressing it promptly saves both hassle and money.
