[SpaceSilver.X1]

what is that cooler behind the front bumper? (on the driver's side, indicated by the red arrow in the picture below)


after I've been driving in extremely heavy rain, it creates a lot of steam, especially when it's really cold(35 to 40 degrees, like today) I assume that cooler is cooling something... is it cooling the transmission fluid, engine oil, coolant or perhaps the turbo? the heavy rain left rainwater on it, so that's how steam was created?

edit: found out that it was called the "auxiliary radiator" with part# 17-11-9-847-023. Supposedly provides extra cooling for the coolant. I guess it gets hot and when rain comes into contact it, the water gets evaporated and becomes steam. (also saw a bunch of small bees stuck to it, so I cleaned them off with a small vacuum attachment)

https://www.getbmwparts.com/oem-part...or-17119847023

[richiro]

Originally Posted by SpaceSilver.X1

what is that cooler behind the front bumper? (on the driver's side, indicated by the red arrow in the picture below)


after I've been driving in extremely heavy rain, it creates a lot of steam, especially when it's really cold(35 to 40 degrees, like today) I assume that cooler is cooling something... is it cooling the transmission fluid, engine oil, coolant or perhaps the turbo? the heavy rain left rainwater on it, so that's how steam was created?

Not sure if this correlates but for the m35i that’s where the intercooler is, on both sides.

[BMWZ4]

I believe both the left/right are simply known as Auxiliary Radiators. The intercooler or charge air cooler is actually just below the primary rad...it's about 3' long by 4" or 5" high

I believe that's the config and could be wrong...no doubt someone will correct me if I'm mistaken

[SpaceSilver.X1]

Originally Posted by BMWZ4

I believe both the left/right are simply known as Auxiliary Radiators. The intercooler or charge air cooler is actually just below the primary rad...it's about 3' long by 4" or 5" high

I believe that's the config and could be wrong...no doubt someone will correct me if I'm mistaken

after driving in heavy rain for hours, I pulled into a Costco parking lot. The driver of the car next to me knocked on my window and yelled "you're radiator is busted! look at all that steam!" I looked towards the front left(driver) side that he was pointing at and sure enough there was a plume of steam coming up. I also thought that the radiator must have leaked or something.


I got out and tried to see where all that ridiculous amount of steam was coming from. I saw part of what looked like a radiator/cooler.. not sure what it was supposed to cool, but all the rainwater was being turned into steam. Fortunately, the steam went away after about a minute or so.

Like I said, it was very cold, just a few degrees above freezing. I'll look at it again when the weather clears... it still has not stopped raining and even heavier rain is expected by Tuesday.

[SpaceSilver.X1]

Originally Posted by richiro

Not sure if this correlates but for the m35i that’s where the intercooler is, on both sides.

apparently it's the "auxiliary radiator" for the xDrive28i. It's only on the driver's side.(as indicated by the pictures above)

the xDriver28i has the large intercooler directly below the primary radiator, just behind the center of the front bumper.

interesting to learn the the M35i has two intercoolers... but with so much more power, I guess the extra cooling of the air for the turbo is needed.