Discovery Overheating: Could Bad Aux Pump Be The Culprit?

Hey there! I had a similar issue with my 2010 Range Rover Sport (those British SUVs, right?). I'd say I have some experience working with cars, mostly basic maintenance stuff. The symptoms you're describing sound exactly like what I dealt with. In my case, it turned out to be a loose cable connection to the auxiliary pump, not the pump itself, thankfully! Took it to my regular mechanic who spotted it pretty quickly. The repair was around 170 Euro, mainly for labor and fixing the connection properly. Before you head to the workshop though, what's your coolant level looking like? And are you hearing any unusual sounds from the pump area? Also, what kind of driving conditions did you notice this problem in, city, highway, or both? Would help if you could share more details about any other symptoms you've noticed. These Discovery issues can be tricky, and the more info we have, the better I can help!

Thanks for the detailed response! My coolant level is actually fine, checked it this morning, but I'm hearing this weird whirring noise from the pump area, especially at idle. It's happening both in city driving and on highways. I've maintained my Discovery pretty well (last service was 2 months ago at 123888 KM), but these symptoms only started showing up last week. The temperature gauge started creeping up gradually, not sudden spikes. I'm really hoping it's just a connection issue like yours and not the entire pump! Gonna get it checked tomorrow, but wanted to gather some insights from fellow owners first. The weird thing is that the noise gets louder when the AC is running. Could that be related? Let me know if you experienced anything similar with the AC correlation too! Appreciate your help!

Hey again! that whirring noise with the AC correlation definitely rings a bell, had exactly the same thing with my Range Rover Sport! When you mentioned the AC making it worse, it totally clicked. In my case, even though I initially thought it was just the auxiliary pump connection, it turned out there was a bit more going on. The whirring noise was actually coming from the water pump pulley, it was wobbling slightly because of a worn bearing. The AC compressor being on added extra load to the belt system, which made the noise more noticeable. The gradual temperature increase you're seeing is super similar to what I experienced. Mine started creeping up over about a week before I got it sorted. The fact that your coolant level is good is actually a good sign, means you probably don't have any major leaks. For my Sport, the final fix involved replacing both the water pump and the auxiliary pump (they were both showing wear). Cost me about 800 Euro in total, but honestly, it was worth it for the peace of mind. The funny thing is, once I got it fixed, I realized how much I'd gotten used to that annoying whirring sound! Let us know what your mechanic says tomorrow! Always curious to hear how these things turn out, especially with these finicky British SUVs we love so much.

Thanks so much for sharing your experience! That's really interesting about the water pump pulley, I hadn't even considered that angle. Now that you mention it, the whirring does seem to have a slight wobbling quality to it. I was hoping it would just be a simple fix like your first case, but I'm mentally preparing myself for a bigger repair bill now. You're right though, these British SUVs can be finicky, but I still love my Disco despite its quirks! I've just called my mechanic and managed to get an early morning appointment tomorrow. I'll definitely keep an eye on that pulley situation you mentioned, it makes total sense with the AC correlation. The fact that your symptoms matched mine so closely is actually quite reassuring. At least I know what I might be dealing with. I'll update the thread tomorrow after the mechanic takes a look. Really appreciate you taking the time to share your experience in such detail. It's exactly what I was hoping for when I posted here!