Originally Posted By: Doug Hillary
Hi,
IMHO the key to successfully using HDEOs in petrol engines is to ensure that they have dual diesel/petrol engine Quality ratings - API or ACEA or both - (a "mixed fleet" lubricant in the Commercial World) and a suitable viscosity
Some facts
1 - Porsche mandated HDEOs for their first engines (1950s - 356) and onwards to the 911/912 Series. They were the Factory fill
2 - Porsche maintained a "dual rated" lubricant requirement (PCMO) up until factory filling with a synthetic lubricant in 1992
3 - Variability in "M","S", "C" etc. series of engine lubricants in 1950-1960s caused me to do considerable research and testing on the use of HDEOs in petrol engines in this period. This was with excellent results in a wide variety of engine families - especially in Europe
4 - All VW and BMC engine families of the time performed best on an HDEO
5 - The minimum standard I used for many years in selecting HDEOs was the CAT Series 3 (and supplements) specification along with the MIL ratings and those from DB (I worked for Caltex-Chevron in Europe during this period)
6 - I have used HDEOs in many of my engines for over 50 years - always with excellent results
7 - I have used synthetic HDEOs in all of my Porsche engines and still do - and they are very widely used in the Porsche community (especially 8 - I use synthetic HDEOs at extended OCIs in a wide variety of friend's and family's engines that range from Toyota, Mazda etc thru GM and Ford to MB and Porsche
9 - The most professional Service Provider in this area (Australian Tropics) uses an HDEO exclusively as his service fill lubricant (Castrol RX Super) and has done so for a decade or two. Engines under warranty or with specific needs get what they require of course. He is BMW Factory trained and very well qualified. The range of vehicles maintained by him and his staff include Ferraris, Rollers, Maseratis, Porsches along with a wide spread of your average vehicles
10 - Many Porsche Service Providers use a 15W-40 HDEO in all
When using an HDEO in any petrol engine care must be given to the engine's lubricant requirement, the lubricant's specification as alluded to above, and to the viscosity requirements in relationship to the expected ambient temperature range of operation
As I stated earlier, Commercially available diesel engine lubricants (Commercial lubricants) that are not dual rated should NOT be used in petrol engines as excessive wear may be an outcome. This wear will most likely occur in the ring/piston/bore area
Pretty much says it all