Z3M radiator - S52 or S54?

[CorvallisBMW]

Does it matter? Are they the same? Thinking of going 3-row and I know the Z3M is a popular option.

[mtech325]

The S54 has thicker core and the bottom section is a little shorter because it's intended to be used with the s54 oil cooler. It's a direct swap replacement for an e30 late model 6-cylinder radiator/e36 cylinder radiator (at least in the e36). The S52 Z3M radiator shows a different part number, so can't confirm the fitment.

For most street cars it's not as noticeable. I put the S54 radiator in my e36 and honestly haven't noticed much of a difference in temps, but it was essentially the same price as a standard e36 radiator so it was worth a try. It seems to be popular with the track car crowd though. In my 24V e30 I have a standard late model e30/e36 radiator and clearance is pretty tight as is even with a pusher fan mounted up front, so just something to think about with the thicker core of the S54. A friend has the S54 radiator in his M60 e30 and it seems to be working well for his purposes.

Here's the thread where I took some pictures showing the differences:

https://www.bimmerforums.com/forum/showthread.php?1826538-OEM-M3-radiator-vs-OEM-Z3M-S54-radiator/page4

[jpod999]

I have the S54 Behr in my M62 swap and it has worked quite well so far. Drops right in with the M20 mounting cups.

[CorvallisBMW]

Thanks for the info guys! My biggest constraint is thickness; there's so little room in an e30 engine bay with an m30, especially between the distributor cap-radiator and the AC compressor-radiator.

I need to take more measurements, but the e28 535i radiator is very large in square area but also very thin. Essentially my 16" pusher fan only covers about 45% of it. If I go with a radiator that is thicker, yet has a smaller square area, the fan essentially becomes more effective at removing heat, as it would cover more like 65-70% of the square area. Just got to make it fit!