Peugeot 508 Coolant Loss

I've had similar coolant issues with my 508! It's a pain. Checked for visible leaks around the radiator, hoses, or water pump? Any coolant in your oil (milky residue on the dipstick)? Radiator cap sealing properly? A bad cap can cause coolant loss.

Thanks for the quick reply! I haven't seen obvious leaks, but I'll take a closer look around the water pump and hoses. The oil seems fine, no milky residue. How can I tell if the radiator cap is sealing correctly? Is there a way to test it?

Without proper testing equipment, it's tricky to be 100% sure about the cap. If it looks damaged or doesn't feel like it's making a tight seal, it's worth replacing. After chasing my tail for weeks, I took it to a workshop. They pressure-tested the system and found a tiny leak I couldn't spot. Cost me 52€. Saved me a lot of headache. Could be air pockets as well.

Thanks for the advice! I'll double-check the cap and look for tiny leaks again. If I can't find anything, I'll probably take it to a shop for a pressure test, like you suggested. I appreciate the help!