We had planned to head to my wife's parents' house bright & early yesterday for Christmas, and I had cleaned up & gassed up the X5 for the hour drive. Got the family and loot all loaded up X5 with plenty of time for us to get there for the Christmas morning church service, but about 3 blocks from home, I look down at the instrument cluster & see the temp gauge pegged to the right. Crap. So we turned around & went back home, transferred everything from the X5 to the e32 and headed out again. Didn't lose much time, but I was stressing out about the thing all day yesterday.
We haven't had the X5 for very long, but I've never seen the temp gauge move past the 12 o'clock position. In fact, on Monday I ended up sitting in it with the engine idling for about 15-20 minutes waiting for a car wash, and the temp gauge was right about the 10:30 position the entire time. We also drove it around a bit that night, about 20 minutes total, and the temp gauge stayed where it should be for that. Yesterday morning it was plenty cold out -- about 0°F -- but it had been parked in the garage overnight, with the heat on all night (to make sure the doors & locks dried out properly after the cold-weather wash), so it was a balmy 60°F in the garage. I left the engine idling about five minutes while we loaded up, so the total running time before I noticed the temp gauge was well under 10 minutes.
I'm thinking/hoping the problem is something simple like the thermostat, or maybe even a misbehaving temp gauge... Any thoughts on that? I haven't had the time to take a closer look at anything; we got back late last night and I'm back at work now, but will definitely break out the Bentley and my meager troubleshooting skills when I get home.
One other thing really had me worried, at least until I did some asking around earlier today; when I checked the oil at the gas station on Monday it was quite low, so I picked up a couple quarts of synthetic 5w30, and it took both of them to get back to the full line. The inside of the oil filler cap had some white/yellow pasty crap on it too. My first thought with that in mind on top of the overheating was "head gasket" so I checked the coolant too; level was fine, and showed no signs of contamination. The pasty stuff is likely just the result of some condensation in there, as it's been quite cold lately, and my wife does a lot of short trips with the X5. Then I found
this thread about the oil separator; makes perfect sense that that thing would be acting up & causing high oil consumption, and is due for replacement.