Over the years, Caterham have had various oil partners, and therefore the recommended fluids / oils have changed over time.
I recommend using known suppliers to avoid fake automotive components.
Engine Oil
For the Duratec engine Caterham recommends a 5w-50 oil.
- Motul Sport 5w-50 Ester Synthetic
- Millers Oils XF LongLife 5w-50 Fully Synthetic (Formerly XFS)
- Comma Motorsport 5w-50 Fully Synthetic
Oil Filter
Caterham now brand their own oil filter, but previously they supplied Fram and UFI filters. There are plenty of oil filter cross-references which allow you to look up alternatives from different brands, for example: https://www.oilfilter-crossreference.com/
- Caterham 380E0003A
- FRAM PH2874
- UFI 23.118.00
Differential Oil
Recommended differential oil by Caterham:
- Motul GEAR Competition 75W-140 Racing Fully Synthetic Car Gearbox & Limited Slip Diff (LSD) Oil
Caterham use Road and Race Transmission in Kent (https://www.rrtransmissions.com) for differential rebuilds and other gearbox services. They have developed their own differential oil designed to reduce LSD noise:
- RRT LS90 GL5
Caterham 420 Workshop Manual 