Site Traffic Information and Cookies

We use cookies (and equivalent technologies) to collect and analyse information on our site's performance and to enable the site to function. Cookies also allow us and third parties to tailor the ads you see when you visit our site and other 3rd party websites in the same online network, including social networks. By clicking 'Agree', you agree to these uses of cookies. If you do not agree or if you would like more information, you can manage your cookie preferences opposite.

Manage cookie preferences

IT'S MORE THAN JUST OIL. IT'S LIQUID ENGINEERING.

  1. Home
  2. CAR ENGINE OIL & FLUIDS
  3. ENGINE OILS
  4. MOTOR OIL VISCOSITY GRADES
  5. 15W-40

15W-40

15W-40 is a very common viscosity grade for diesel engine oil. GTX Diesel is a 15W-40 diesel engine oil formulated to help extend engine life.

THE RIGHT 15W-40 OIL FOR YOUR ENGINE

If you need a 15W-40 diesel oil, Castrol® GTX® Diesel helps extend engine life, protecting against the wear and tear of severe weather, rough roads and heavy tows. As a 15W-40 viscosity grade, it flows like a 15 weight oil from start up in Winter, but provides the protection of a 40 weight once the engine reaches full operating temperature.  

 

When your owner's manual calls for 15W-40 diesel oil, Castrol® GTX® Diesel has the ability to extend your diesel engine's life in a variety of applications and duty cycles. It provides superior protection, conforms to the strict requirements of PC-11 engine oil technology and can be used in diesel engines where API CK-4, CJ-4 and below is required.

Castrol GTX Diesel 15W-40

Castrol GTX Diesel 15W-40 is designed for today’s diesel car and provides extra protection against diesel engine problems, like soot and harsh deposits, that diesel engine faces every day.
Castrol MAGNATEC DIESEL 15w-40

Castrol MAGNATEC DIESEL 15w-40

Castrol MAGNATEC DIESEL contains dedicated diesel technology and breakthrough DUALOCK molecules that cling to critical engine parts and lock together forming an impenetrable force field of protection that dramatically reduces both warm up* and stop-start wear by 50%**.
^Global average from 50 cities, Castrol Stop-Start Index 2014
*Tested versus the sequence IV A API SN wear limit.
**Tested versus the CEC OM646LA ACEA wear limits.