Hey there! I had a similar issue with my 2006 Mazda BT-50. I wouldn't consider myself a car expert, but I'd say I have some experience. In my case, the electric auxiliary heater was defective and it was causing overheating. I took it to my local garage and they helped me out. Ended up costing about 350 Euro to replace it and fix the issue. To help you better, can you share if you've noticed any other symptoms? Do the issues persist even after refilling the coolant? It could also be a leak, so any information would be useful. Hang in there! I know car troubles can be annoying, but you'll sort it out. Cheers!

Hey, thanks for your quick response! Appreciate the insight. So, the symptoms persist even after refilling the coolant. There's a weird noise coming from the engine as well, so maybe a leak could be part of the problem, not sure. By the way, my BT is on 147530 KMs. I got it serviced recently, but this issue popped up out of nowhere after that. Do you think this heating issue can turn into a serious problem if I leave it unattended for a while? Thanks again for your help!

Howdy! Sorry to hear the troubles persist. Considering the noise from the engine and the persistent heating issue even after refilling the coolant, I reckon there might indeed be a leak somewhere. In my experience, disregarding such an issue can potentially lead to serious engine damage due to overheating, so getting it checked out sooner would be a smart move. In the worst-case scenario, the engine block could literally crack due to overheating, which would be a quite costly fix. Considering that your BT is already high in mileage, I suggest having a thorough check in your local garage. In my case, the mechanic identified the faulty PTC heater using some sort of diagnostic code reader. You can also ask them to check on any coolant leaks and, if there are any, to perform a pressure test to pinpoint the exact location. Hang tough and get it sorted ASAP. I wish you the best! Cheers!

you're a lifesaver! The consequences sound more serious than I thought. I'll take my BT to the local garage first thing tomorrow. They've been good in the past, so fingers crossed they'll figure this one out too. And yes, they do have a diagnostic code reader, so should be able to get to the bottom of it. Thanks a bunch for your advice and for sharing your own experience. It really helps me to understand what might be going on. I’ll be sure to get back to you with an update. Cheers!