Engine overheated. Mechanic said water pump, but come to find water around water

08bimmer335xi · 10-28-2018, 12:52 AM

While I was driving my 2008 BMW 335xi, after about 15 minutes of driving, a yellow light came on telling me to "drive moderately." After about 2 more minutes, the red light came on telling me to shut off my engine and allow to cool. I shut off the engine and the oil temp was just above 160°. I allowed it to cool and drove about 2 miles and it came on again. Had it towed. I took it to a mechanic and was told it was the water pump (mind that the water pump and thermostat were replaced just over a year ago). I haven't replaced them again yet.
I tried to start it again and it wouldn't start; everything came on (accessories, A/C, etc.). Suspected battery so we tried jumping it and it started right up. It then started saying "charge failure," and "airbag malfunction." Went to take the battery out and found that I had a leak in the battery compartment. There was about 2 in of water that had corroded the 2 red wires in the bottom of the box (I have no idea what these wires are called, nor how they connect as they are not connected to anything now).
The battery is still out, but I have no idea where to go from here. Is the water in the battery compartment the root cause of all this, or is there more to it? What should I do/how do I go about fixing the red wires?

Efthreeoh · 10-31-2018, 02:34 PM

The red wires are the main battery cables that end at the junction box and under the hood. The cables in the battery compartment are short and just travel to the cable lugs that pass the electricity through the metal bodywork of the wheel well. Pull the right rear fender wheel well liner out and you'll see the other side of the lugs. Hopefully you just need the new cables from the BST to the lugs.

If you go to realoem.com you can find the battery compartment equipment and see what I'm talking about. Item 4.

https://www.realoem.com/bmw/enUS/sho...diagId=61_1946

10-28-2018, 12:52 AM	#1
08bimmer335xi Registered 0 Rep 1 Posts Drives: 2008 BMW 335xi Join Date: Oct 2018 Location: Provo, UT iTrader: (0)	Engine overheated. Mechanic said water pump, but come to find water around water While I was driving my 2008 BMW 335xi, after about 15 minutes of driving, a yellow light came on telling me to "drive moderately." After about 2 more minutes, the red light came on telling me to shut off my engine and allow to cool. I shut off the engine and the oil temp was just above 160°. I allowed it to cool and drove about 2 miles and it came on again. Had it towed. I took it to a mechanic and was told it was the water pump (mind that the water pump and thermostat were replaced just over a year ago). I haven't replaced them again yet. I tried to start it again and it wouldn't start; everything came on (accessories, A/C, etc.). Suspected battery so we tried jumping it and it started right up. It then started saying "charge failure," and "airbag malfunction." Went to take the battery out and found that I had a leak in the battery compartment. There was about 2 in of water that had corroded the 2 red wires in the bottom of the box (I have no idea what these wires are called, nor how they connect as they are not connected to anything now). The battery is still out, but I have no idea where to go from here. Is the water in the battery compartment the root cause of all this, or is there more to it? What should I do/how do I go about fixing the red wires?
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10-31-2018, 02:34 PM	#2
Efthreeoh General 19032 Rep 19,655 Posts Drives: The E90 + Z4 Coupe & Z3 R'ster Join Date: May 2012 Location: Virginia iTrader: (0)	The red wires are the main battery cables that end at the junction box and under the hood. The cables in the battery compartment are short and just travel to the cable lugs that pass the electricity through the metal bodywork of the wheel well. Pull the right rear fender wheel well liner out and you'll see the other side of the lugs. Hopefully you just need the new cables from the BST to the lugs. If you go to realoem.com you can find the battery compartment equipment and see what I'm talking about. Item 4. https://www.realoem.com/bmw/enUS/sho...diagId=61_1946 Last edited by Efthreeoh; 10-31-2018 at 02:40 PM..
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