https://www.opieoils.co.uk/t-car-engine ... ained.aspx
SAE 60 is in fact 24cst viscosity at 100°C!
This is 33% thicker than an SAE 50, 70% thicker than an SAE 40 and over 100% thicker than an SAE 30!
So, what's the problem with this thickness?
Well, this is measured at 100°C and at lower temps (70-90°C) all oils are thicker than at 100°C so the problem is compounded to some extent. The downsides of such a thick oil (when not specified) are as follows:
Additional friction, heat and wear.
A reduction of BHP at the wheels
Lower fuel efficiency
The thicker the oil is the more friction and drag and the more power the engine needs to move it around the engine which inevitably translates to less at the wheels.
So, when do we spec a thicker oil?
We sometimes recommend a 10w-50 engine oil, but only in these circumstances:
If the car is heavily modified and heat/oil temperatures are excessive.
If the car is used on track and heat/oil temperatures are excessive.
If it's required by the handbook.
Our criteria for this is based on oil temps as an SAE 40 semi-synthetic can handle around 110°C for limited periods whereas a proper synthetic SAE 40 can handle 120-130°C for prolonged periods due to its thermal stability.
- 2002 Toyota Caldina GT-Four N-spec
- 2004 Toyota MR2 SMT PGP
- 2006 Toyota Rav4
- 2004 Toyota MR2 SMT PGP
- 2006 Toyota Rav4