These diesels also have a turbo on them too, which sucks in a TON of air. It also raises intake temperatures since the exhaust is swirling arouind right next to it--hence the need for intercoolers.

Is it possible to split the two - air induction and battery cooling?

The battery cooler duct was missing when I got the car, but I just bought one that I plan to install soon. You can't really split them using the stock battery duct.

Sucking hot air in from the engine compartment rather than cool air from the front of the car is probably not the best thing. I may end up going back to the USA lights if it ends up being too much modification/trouble.

I am actually glad I have the sock on there; there is a lot of cotton debris on it that it kept from getting inside the air cleaner housing.

I just made a 2 hour trip and the car really heats up on the long hills. And when it gets hot it really loses power. It's probably all that hot air getting sucked in.

I know what you mean. The cottonwoods are going crazy right now up here. It looks like snow in some places.

Well, I understand now why my Euro install works fine with the air intake assembled normally.

I should have remembered this originally but I guess memory fades with age.

Gotta go back to how I ended up with Euros in the first place.....In November of 07 I was rear ended whilst heading down I 85 in Atlanta and got shoved into the rear of the car in front of me (BTW, that car sped away never to be seen again). Anyway, my passenger side headlight was crushed pretty good and I happened to come upon the Euros right about then so I made the switch.

Upon installation I realized that the mount area for the right light had been bent and in order to get the light to look flush with the top of the hood I used several washers and longer screws to mount the unit. Never really gave it a second thought until this thread got me wondering. So I took a close look the other day and now see that those washers stand the light assembly about 1/4" off of the face of the mounting area. What would normally be effectively sealed actually offers a pretty decent total area for air to flow into the intake pipe.

I can see where the normal attachment would seem to restrict air intake and potentially cause the issue described by Squiggle Dog. With the assembly mounted tight to the frame there wouldn't be much space for proper air flow. I wonder how others have done it or if gasser W116 with Euros have a different method for air flow?

Ah, it is all starting to make sense now! Here is a 1979 300SD listed on craigslist with Euro lights. We can see that the intake hose is disconnected from the intake port and points straight forward. The gasser models use an air cleaner on top of the engine that apparently sucks in hot air from under the hood--the diesels really seem to need the cold air intake.