2012 BMW X5 engine overheat after driving on highway for about 25 miles.

[zhangzheng0529]

My X5 E70 just passes 60,000 miles last month. However, last Monday, after I drove it on the highway for about 25 miles, it sents out warning that Engine temperature is high. Please continue to drive moderately. But when I pulled over my car and let it cool it down for a couple of minutes, it looked like it's good to go again. So I made it back on the road, but after about 25 miles, the same problems came back and I have to stop again and turn back home. I was a bit baffled at that moment since this was the first time I encountered such a problem and had never experienced this when I drove it locally. <br><br>On the way back, the engine had the same problem on this 25 miles phantom. I had to take it to a local car repair shop. The mechanic told me it's about a bad thermostat on my car because he found a temp difference after testing for the temperatures of two hoses in and out of the thermo.<br><br>So I trusted them and let them replace the thermostat with a new one. They charge me 240+85(inspection) for labor. I don't know if it's a rip-off but it looks expensive for me.<br><br>However, with the new thermo in place, I drove back on the highway and this 25 miles phantom is still there. Problem was not solved at all.<br><br>Yesterday I had to take it back to the shop again. This time mechanic took it on the highway and tested the water pump while he's driving.<br><br>He found the water pump stopped spinning and couldn't running again after he drove around 25 miles. Yet, as long as you pull the car over and restart the engine, it would recover and work as if it's normal for another 25 miles drive.<br><br>He suggested that I have my water pump replaced.<br><br>This time I am a bit suspicious of the mechanic's judgement and expertise 'coz I do not want to see my car still have the problem after I spend another 500+ bucks on a water pump replacement.<br><br>Does anybody know what may have caused this problem except the water pump itself. Could it be the fuse associated with the water pump. Once the fuse is worn out or blown, could the water pump still be working but have a glitch like this? Could it be an electrical issue instead of a mechanical one?<br>Could it be circuit or something else like distribution box whatsoever?<br><br>Thanks very much for your kind response in advance. I appreciate your advice and story sharing. Feel free to weigh in on this and I will be grateful if you could tell me your thoughts and ideas on this based on your expertise and experience.<br><br>Steve 

[pbonsalb]

What engine do you have? You don’t know much about your car so you have no choice but to trust mechanics. Most are trustworthy. Probably if it is an N55, it’s the electric water pump like the mechanic said. Often mechanics replace both the thermostat and water pump at the same time on these motors because they are in the same area and it’s a pain to get to.

[MarcoZandrini]

You need to take your car to a reputable indie shop that specializes in bimmers. Try www.bimrs.org to find a shop in your area. The shop will have all of the proprietary BMW software to properly diagnose the problem.

[White94RX]

Right. You need to find a new mechanic. If he doesn't scan your vehicle for fault codes as the very first step, then he's not doing it right. If you got an overheating message, then there will be a fault stored. I would assume it's for the water pump. But your mechanic should have done this first and not just thrown a thermostat at it.

[zhangzheng0529]

Right. You need to find a new mechanic. If he doesn't scan your vehicle for fault codes as the very first step, then he's not doing it right. If you got an overheating message, then there will be a fault stored. I would assume it's for the water pump. But your mechanic should have done this first and not just thrown a thermostat at it.

Yeah, it's been solved, It's water pump. The mechanic said it was an electrical glitch with one of the 4 gears. He charged me 480 for labor + inspection. I got the thermostat + water pump for nearly 400 bucks on fcp euro. So it costs me little less than 900 $ in total for thermostat + water pump replacement.

Thanks for your kind reply.