Renault Spider low heating output

Interesting. I had a similar issue with my old Saab 9-3. The heater was blowing cold air and there was an error code relating to the cooling system. Did you check for any coolant leaks around the valve or hoses? That could also contribute to low heating performance.

Thanks for the suggestion! I haven't noticed any visible coolant leaks, but I'll double-check more thoroughly. Where was the leak located on your Saab, if you don't mind me asking?

On my Saab, the leak was actually pretty subtle and hard to spot at first. It was a slow weep from the valve itself, evaporating before it hit the ground. Given the error code and your low heat, and especially because you can't find a leak, I'd honestly suggest having a workshop take a look. It could save you a lot of time and frustration.

Appreciate the advice! I checked again for leaks but still found nothing. I'll take it to a workshop and get it checked out. Turns out it was the water valve and after the replacement I had to pay 95€ Thanks again!