No Coolant Level Sensor?? 2001 X5

[DSAviate]

OK, I managed to get my local dealer to reluctantly cough up information on this anomaly . . . and it seems to be the best explanation so far.

X5SND - I agree that anyone with an E53 now-a-days had better be into routine maintenance and vigilant inspections. However, having a warning to advise me that one of my coolant lines just broke or fell off would be a very nice feature. Of course one would probably see white smoke coming from the engine area (daytime), but maybe not . . . it depends on where the fluid escapes. With a catastrophic loss of coolant, the low level sensor would trip several valuable seconds before you would get a red over-temp light . . . assuming you did get an over-temp light now that the temp sensor may be surrounded by air. When trying to save one's engine while moving to the side of the highway, or find some light at night, I'd prefer all the any advance notice I can get. I'm sure you check your oil level frequently as well . . . but the low oil level indicator lamp is a NICE backup that something has just run amuck.

My very helpful parts guy finally realized that I had done a fair amount of research and sought out the 30 year technician for an explanation. The salty tech immediately said, "it's an '01 X5 3.0i, right?" He claimed that there was a certain run of E53s in 2001 that were equipped with the new expansion tank that houses the low coolant sensor, WITH THE LOW COOLANT SENSOR INSTALLED, but, . . . they never wired the sensor because they hadn't yet updated to OBCs to make use of the signal.

He further relayed, that in the years following this production idiosyncrasy, many BMW techs wasted hours and hours looking for the "disconnected" harness to plug back into the sensor. The official word slowly got out that there is no harness to find. He also said that the OBC doesn't miss the signal because it isn't programmed to receive it. My experience has been that if you unplug virtually anything on the truck, especially under the hood, the OBC will not be happy. But how many of us have unconnected sensors and no advisory whatsoever.

So, I have removed my sensor so no one else wastes time looking for a non-existent harness. I will increase frequency of my periodic review of the coolant system and scan the temp meter a little more often.