Colorado Low Coolant Check Engine Light

Low coolant can be a tricky one. First thing I'd check is the radiator cap – make sure it's sealing properly. It's like the lid on a pressure cooker; if it's not tight, you lose pressure (or coolant in this case). Also, have you noticed any leaks around the engine or hoses? Sometimes, trapped air pockets can cause issues too, like an air bubble in a plumbing system. Is your cooling fan working correctly? Is the coolant reservoir cap tight?

Thanks for the suggestions. I'll check the radiator cap and hoses for leaks. How would I identify air pockets, and could they really cause such a consistent drop in coolant level?

Air pockets can mimic low coolant symptoms, but they wouldn't usually cause a consistent drop. Think of it like this: the air pocket takes up space, then burps out, leaving a void the system tries to fill. If you're constantly topping off, and still seeing the light, it's likely something else. Given the mileage and the persistent low coolant, it might be worth having a shop pressure test the system to rule out a small head gasket leak. Better safe than sorry, as that could lead to bigger problems down the road.

Alright, thanks for the detailed explanation and the head gasket tip. I took it to a workshop and they found a leak at the thermostat housing. Replaced the gasket, topped off the coolant. Total cost was 52€. No more check engine light!