I'm familiar with the use of air intercoolers/charge air coolers to cool the intake charge (usually on turbocharged engines). But this BMW engine seems to use liquid to cool the intake charge. Which liquid is used (water?) and how exactly is it managed? Certainly looks pretty nifty.

enter image description here

  • 1
    It either it shares coolant from the radiator system or it has it own separate water supply....f80.bimmerpost.com/forums/showthread.php?t=983790
    – Moab
    Apr 30, 2016 at 14:17
  • modine.com/web/en/…
    – Moab
    Apr 30, 2016 at 14:18
  • 2
    I'm sure it's the same 50/50 mix as is used in the radiator, but is its own separate system. The coolant in the engine would be too heat soaked to do the job, so from an engineering standpoint you'd want it separate. The reason to use antifreeze in it is for the same reasons you'd use it in your engine: anti-corrosion; anti-boil; anti-freeze. Gives the coolant a much broader range than if it was just water all by itself. Apr 30, 2016 at 21:45
  • 4
    To add to what @Pᴀᴜʟsᴛᴇʀ2 said: If you buy it from the dealership then its made of Unicorn Rainbows. But if you buy it from a regular euro parts store its coolant.
    – race fever
    Apr 30, 2016 at 21:49
  • @timbo It does look nifty. Not so familiar with BMW's but love looking at pics of what's under the hood. May 2, 2016 at 22:51

2 Answers 2


If it's anything like the BMW M4 GTS, it's water. Purely and simply water atomised into the inlet tract.

This link contains more information.


That is coolant running through the charge air cooler (inter cooler). Many engines just use the same coolant and water pump from the normal engine cooling system to circulate the coolant mixture through the charge air cooler. Since we are on the topic of BMW I will note that the N63 V8 uses a separate cooling system and pump for its charge air cooling.

  • The M3 definitely does not inject coolant from the cooling system into the inlet manifold. Feb 6, 2018 at 16:00

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .