P00B7: Engine Coolant Flow Insufficient / Low
Severity: medium
What it means: The engine computer sees coolant flow or temperature behavior that looks like the coolant is not circulating enough—often a sticking thermostat, weak water pump, air in the system, or a related sensor.
Safe to drive? Short trips only if the temperature gauge stays normal. If the gauge climbs or a low-coolant warning appears, pull over and shut it down.
Common symptoms
- Check-engine light with P00B7
- Low coolant warning
- Temperature gauge rising
- Sweet coolant smell or visible leak near the water pump/thermostat
Likely causes, ranked
- Thermostat stuck partially closed or housing leakShop
- Water pump failing or leakingShop
- Air pocket / incorrect coolant level after serviceDIY or shop
- Coolant temperature or flow sensor faultShop
Vehicle-specific notes
- :
DIY or shop?
Checking level and looking for leaks is DIY. Pump and thermostat jobs are usually shop work on transverse engines.
Vehicle notes
- Audi Q5 2.0T: owners often see coolant loss from the water pump/thermostat area along with flow-related codes. See the related Q5 water-pump answer.
Sources
Safety / mechanic note
Driving while overheating can warp the head or destroy the engine. Verify with a mechanic.