Seeking Advice on Overheating Issue and Check Engine Light in 2012 Mazda 3 Diesel

Hey there! I've actually run into a similar issue with my 2010 Mazda 6. I'm by no means a mechanic, but I do enjoy tinkering around with cars in my free time, so I guess you could say I have some experience. In my case, the issue wasn't with the coolant thermostat, but it turned out to be damage to the wiring harness. I took it to my local workshop, where they quickly diagnosed the problem. They repaired the entire wiring harness, not just the damaged section and that cost me around 170 Euro. They were super professional and solved the problem in no time. Could you share more info about your car, like recent repairs or maintenance, how many miles on it, and so on? Might help in getting to the root of your issue quicker!

Hey! Thanks for getting back to me so quickly. It's cool to hear you're into tinkering – I wish I had more time for that. The thing with my Mazda, she's been to the moon and back sort of – clocking in a whopping 267689 KM on odometer. Last tune-up was pretty recent, just got the brakes changed and an oil filter replacement, but nothing too major. I didn't suspect it was the thermostat at first either, I felt like with such a high mileage, it could have been an issue with the engine itself. However, I'll definitely have my mechanic check the wiring harness as well. Your tip is much appreciated! Fingers crossed it doesn't cost me an arm and a leg. Cheers!

Hey there! No worries at all, I'm glad I could help (even if it's just a tiny bit)! 267,689 km, wow, your Mazda has seen a lot, eh? If your mechanic is going to check out the harness, they might also want to check your water pump while they're at it. Given the age and mileage of your car, it could also be causing your overheating issues. On my old 2010 Mazda 6, I ended up needing to replace my water pump at around the same mileage. When it broke, it was a similar story - overheating with the check engine light on. It was somewhat expensive (ran me about 300 Euro), but nowhere near as bad as having to replace the engine! Anyway, hope it's something simpler (and cheaper) for you. But even if it's a pricier fix, remember that she’s an old warrior and deserves to be treated well. Fingers crossed for you and your car! Good luck and keep us posted on how things go. Cheers!

Hey! Appreciate your fast response and even more the concerns. Definitely gives me more to think about. You might be right about the water pump, I hadn't thought about that before. I'll get my mechanic to give it a check. She sure has seen a lot, but she's my old workhorse, and I want to keep her on the road for as long as possible. I gotta say, you've made this whole situation seem a lot less daunting, thanks heaps for the valuable insights. And if it does hit my wallet a bit, like you said, it'd still be cheaper than a new engine! I'll keep you all updated. Here's to hoping for a cheaper fix! Cheers!