Quote:
|
Originally Posted by FlyLo
Lower weight oils are recommended by manufacturers for the purpose of getting a better CAFE rating, whereas 20/50 has yielded a better experience in engine wear. Note, this is in an area where the temperature NEVER gets below 20 degrees F. His recommendation would be different for colder climes.
|
Yea, but...
Many manufacturers are recommending 5W30 or even 5W20 in large part because of the CAFE (Corporate Average Fuel Economy) ratings. However, Lotus doesn't need to worry about CAFE ratings (our car already exceeds the required standards, and since they only sell one model, it doesn't need a low rating to off set a gas guzzling SUV's poor mileage). Lotus requires 5W40 oil which is already "thicker" than most manufacturers use in their engines.
Modern engines (including ours) are made to much tighter tolerances then in the past, and as a result, don't need "thicker" oil to "fill in the gaps" in the bearings - in fact, they need the proper "thinner" oil to flow properly to all internal parts of the engine. 5W40 is probably the proper "thickness" of oil for our engine for all around use - you might want a bit thicker for serious track use, but that's it.
Just because an Aston Martin service manager decides to use a thicker oil is not a good enough reason to over-ride what Lotus recommends.