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Castrol B 373 Racing Mineral Car Gearbox Oil

Castrol B 373 Racing Mineral Car Gearbox Oil


Castrol B 373 Racing Gear Oil - 1 Litre

1 Litre


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  • Description
  • Specifications
  • Technical Info
  • Shipping Explained

Castrol B 373 Racing Mineral Car Gearbox Oil

Castrol B373 is a mineral based extreme pressure gear oil which combines limited slip performance with excellent load carrying ability. 

Castrol B 373 is particularly suitable for use in limited slip final drives in competition vehicles.


PDF Downloads:

Download the Technical PDFDownload the Safety PDF


  • Specifications
    • SAE 90
    • API GL-6

Technical Information:

SAE Viscosity Rating: SAE 90
Relative Density @ 15º C: 0.910
Viscosity @ 40º C cSt: 202
Viscosity @ 100º C cSt: 17.8
Viscosity Index: 95 (min)
Flash Point (open) º C 270
Pour Point º C -12
Phosphorous, % wt : 0.26%


SHIPPING IS FREE* for orders of £75 and over , regardless of the weight of your order.
We've tried to keep all other shipping costs as low as we can.

Carriage starts at just £0.95 (inc VAT) for small items, with our most common courier rate set at £5.99 for orders of 5kg (enough for 5 litres of oil).

  • *Free shipping is available for UK Royal Mail, UPS Access Point™ (click & collect) and standard UK courier services (not express / priority / islands).
  • Courier surcharges mean we are unable to offer free "to the door" courier shipping from us in Cornwall up to Highlands / Grampian in Scotland - and because we send a lot of liquids, not every courier option is available to us. UPS Access Point™ (click & collect) is available as a free shipping option across Scotland, Wales and England, wherever there is a UPS Access Point™ Location.
  • Carriage charges are based on weight - please see our table of carriage costs for full details (although adding an item to your cart and viewing the calculated carriage is often easier!).
  • Priority shipping is also available.

How long will it take to get my order?

We give an estimate of delivery dates as you shop and in your basket. The vast majority of items are held in stock and dispatched from our UK warehouse and we'll do all we can to get your order to you as quickly as possible.

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