Seat Formentor Diesel Engine Warm Up Issue

Interesting issue! I had something similar happen with my old Volvo V60. The symptoms sound very familiar: engine taking forever to warm up, and eventually a check engine light. In my case, it turned out to be a problem with the active grille shutters. Basically, they're supposed to open and close to regulate airflow and help the engine warm up quickly, especially in colder weather. When they get stuck closed, you get restricted airflow and the engine struggles to reach operating temperature. Have you checked the fuse for the active grille shutter system? That was the culprit in my case.

That's really helpful to know! I hadn't even considered the active grille shutters. Where exactly is the fuse located? And is it something I can check myself, or would I need special tools or knowledge?

Happy to help. On the Volvo, the fuse was located in the main fuse box under the hood. Your Formentor should have a similar setup. The owner's manual should have a diagram showing the location of each fuse. You can usually pull the fuse out with a small fuse puller (often included in the fuse box) and visually inspect it. If the little wire inside the fuse is broken, it's blown. While it's technically something you could check yourself, I'd recommend taking it to a trusted workshop. Modern cars are complex, and fiddling with electrical systems can sometimes cause more problems than it solves. Plus, they can properly diagnose the issue and make sure everything is working correctly. They'll probably check for any error codes stored in the engine control unit (ECU) as well.

Took it to the workshop, and you were spot on! The fuse for the active grille shutter was defective. They replaced it, and now everything's running smoothly. Engine heats up normally, no more warning lights, and the temperature readings are correct. Cost me 52€, which is a relief. Thanks a bunch for your help!