Leslie said:
So, the fact that this bottle of, Havoline SAE 20W-50 says API SL, doesn't mean much?
Well, Yes and No. API does mean that it’s wet and slippery, but API Sm is the weakest oil service rating in the industry today. API SM fails to meet the minimum requirement of most vehicles on the road in America today. SAE 20/30/40/etc, 10W-40, 20W-50 or even 15W-40 is a lower quality base stock than most 5W-30 and any 5W-20 products.
Every common brand makes a product that is ACEA A3/B3 approved. But, 90+% of the products made by each of those brands fails to meet ACEA A3/B3. That said, an API oil might give enough for a 50 horse Series. I don’t know what they asked for OE in the 50s?
Engines are designed with valve trains that complement crank bearing clearance, etc. Thicker oil increases the shear forces in bearings and journals at high speeds. An engine with a high shear force valve train that is expected to operate at high speed will tend to require a thicker oil to protect that valve train. But, it must also have crankshaft clearances that accommodate that oil or bearing problems will result. The thicker oil may also require modifications to pistons, rings and even connecting rods or oilers to insure appropriate oil flow for cooling and flushing of the piston & rings.
I n my opinion brand and weight mean very little compared to service ratings, of which there are 14 ACEA service ratings, a few pertinent API service ratings, two pertinent ILSAC ratings and at least a dozen proprietary service ratings that are generically important (and dozens that are less significant).
http://www.infineum.com/information...ar Engine Test Category For API SM - 2008.pdf
Here is a chart from 2007 that says what is needed for API, compare that with ACEA requirements. Or even Ford.
http://www.infineum.com/information/acea2007_gasolineanddiesel.pdf
http://www.ilma.org/resources/ford_2004_my.pdf
What you will find is that: The ASTM sequence IIIE is run 64 hours for API approval but must be run 128 hours for the Ford proprietary rating.
The ASTM sequence IIIF is run 80 hours for API approval but must be run 160 hours for the Ford proprietary rating.
Here is an example of the huge spread API offers.
BMW and Toyota Prius (depending on year and model) both require 5W-30, but there is no 5W-30 product that is approved for both. Any 5W-30 that is approved for the BMW
is not appropriate for the Toyota. Any 5W-30 that is appropriate for the Toyota is not approved for the BMW. But, both are API 5-30.
Once we understand the ratings a little better, we can identify the deception.
ILSAC, the GM ratings and several others include catalyst compatibility, O2 sensor compatibility and fuel efficiency requirements. When oil bears the statement: "Meets/exceeds engine protection requirements of ILSAC/etc" instead of” Meets all requirements of ILSAC/etc" it is a red flag that the other requirements were not met.
A product data sheet will often show the Sulfated ASH, Phosphorous and Sulfur (SAPS) content that are Catalyst/O2 compatibility requirements of ILSAC, GM, Ford, Chrysler, etc. And the API donut includes a specific spot that will show energy conservation requirements (or be empty when the product fails).
So, the labeling only succeeds in misleading us if we don't understand enough about the rating systems.
Since the OEMS all copy the ILSAC or ACEA SAPS limits, we don't have to memorize a different catalyst standard for each car.
ACEA has a whole bunch of different ratings that are either new or still used during a transition period, but they all follow a rating system that makes them easy enough to understand/remember.
The OEMS also follow patterns. Any VW ABC.01 rating is simply an improvement of a VW ABC.00/ABC. Any ford oil rating starts with WSS-M2C, so only the last three digits and suffix are significant. And they still follow patterns.
Most American OEM ratings simply duplicate API and ILSAC. And the Engine protection portion of ILSAC always duplicates API. So, the current GM 6094M is nothing more than the current ILSAC rating! But, the GM 4718M is the current ILSAC rating plus some much more stringent engine protection sequences. GM has been using the same rating number each year, but it is automatically updated as ILSAC and API change.
So, it is complicated, but not as complicated as it sounds on the surface and it is manageable.