Infiniti M Diesel: Overheating + Engine Light Mystery Solved

Hi there! I had some experience with a similar issue on my 2012 Infiniti Q70 diesel (I'm a hobby mechanic with some basic experience). Had the exact same symptoms engine light and overheating problems. Turned out it was the radiator shutter wiring harness that was worn out behind the front bumper. Got it fixed at my local Infiniti specialist for about 215€. Really common issue with these models! What's your mileage and have you noticed any other warning lights or unusual behavior? Could help pinpoint if it's the same problem I had. Tip: Don't wait too long to get it checked these cooling issues can get worse pretty quickly.

Thanks for your reply! I'm at 190608 KM and just had my service last month. Yeah, no other warning lights showing up, just the engine light and temperature gauge running higher than usual. Good call on the radiator shutter wiring I'll definitely get that checked out. Did you notice any particular sounds or behavior before you got it fixed? Really appreciate the tip about not waiting too long planning to take it to my mechanic this week just to be safe.

Hey again! Yeah, now that you mention it, I remember before I got the wiring fixed, my car was making this subtle electric whirring noise from the front when starting up kind of different from the normal startup sound. The temperature would usually creep up about 10-15 minutes into driving, especially in stop-and-go traffic. Just a heads up from my experience when I first noticed it on my Q70, I tried to save some money by having a regular mechanic look at it, but they couldn't properly diagnose the wiring issue. Ended up having to go to the Infiniti specialist anyway. Since you're at 190K km (mine was around 170K when it happened), it's right in that range where these issues typically show up. One quick check you can do before heading to the mechanic try listening for that whirring sound when you first start the car in the morning. If you hear it, it's probably the same issue I had with the radiator shutter. Keep me posted on what your mechanic finds! Really curious if it's the same problem.

Thanks so much for all the detailed info! You know what, I just went out to check and I think I can hear that whirring sound you mentioned it's definitely different from the usual startup noise. Really glad you mentioned the specialist thing too was actually thinking about taking it to my regular mechanic, but I'll book it with the Infiniti specialist instead. Rather spend a bit more and get it fixed right the first time. Will definitely keep you posted once I get it checked out next week. Really appreciate all your help and advice on this!