S85 Performance Oil Cooler
by Radtec
Build Journal: a special series
Getting old doesn't have to be draining.

I bought my M5 in July 2020, by September I was losing half a liter of oil every 1,000 kilometers and my undertray was spoiled in an oddly specific pattern.

The oil cooler was cracked.

I rushed a replacement OE unit for a quick fix. I've sinced swaped to a higher temperature thermostat and revisiting the V10's coolant needs.

In this Special Series, I document the original failure points of the OE unit, my unboxing impressions of this improved oil cooler along with installation notes.

- Matt / @m3_epoustouflant

No more cracks.

Radtec fixed the cracking welds issues by redesigning the oil lines fittings and using TIG welds across the cooler.

No more leaks.

The fittings also fit the larger OEM o-rings. More details in installation notes.

Resilience through increased capacity [...]

Radtec uprated the capacity by 0.25 liters and the cooling core to 60mm.

and improved air flow.

The Radtec cooler is easily distinguished from others by its signature cow using 1050 Commercial Grade aluminum.

It's black, just like OEM.

The finish is powdercoated to last forever.
Get your performance cooler
S85 Performance Oil Cooler
S85 Performance Oil Cooler
S85 Performance Oil Cooler
S85 Performance Oil Cooler
S85 Performance Oil Cooler
S85 Performance Oil Cooler
S85 Performance Oil Cooler
S85 Performance Oil Cooler


S85 Performance Oil Cooler

  • Factory Direct Process
Regular price$720.00


  • Made from 1050 Commercial Grade aluminum
  • Made in the UK
  • Factory plug & play fitment 
  • TIG welded
  • Uprated 60mm core
  • Cowl designed for improved airflow & cooling
  • Powder coated in black for an OEM like finish 
  • 1 year warranty

Installation Notes

The oil cooler fits with OEM hardware. It's a bumper off affair - get ready to spill some oil. Have a jug nearby to replenish or plan a full oil change.

Darren @ radtec
A British supplier to the greats.

Radtec is a well-known name throughout all forms of vintage and classic motor-sport and claims to be the largest manufacturer of bespoke built classic aluminium radiators in Europe.

They've most notably been assigned the OEM contract for Koenisseg.

Cooling is in their family bloodlines: they have been supplying the classic car market for over thirty years.

They've been expanding their BMW M offerings as our cars age. I'm eager to see what more we can bring to market together.

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