Synthetic or Not? OIL

<div class='quotetop'>QUOTE(molgrips @ Nov 19 2006, 11:52 AM) [snapback]351701[/snapback]</div>

Most people would call the 0w40 weight oil a heavier oil than the 5w30. The 0w40 has lower viscosity at wintertime cold engine temperatures and will allow for easier cold starts with less wear. Most of the time though, when the engine and oil are at operating temperatures, the 0w40 oil has higher viscosity and higher HTHS measurements, offering reduced fuel economy but greater engine protection and oil longevity.

Can you tell us what oil viscosity and specification Toyota recommends in the UK?

 

<div class='quotetop'>QUOTE(LongRun @ Nov 20 2006, 12:20 AM) [snapback]351983[/snapback]</div>

He's posting from the UK. In Europe, most car manufacturers recommend higher viscosity oils than they recommend for the same cars sold in the USA. In the USA lower viscosity oils help the cars do better with the CAFE standards. In Europe the higher viscosity oils protect the engines better and longer. This works well with the longer engine oil change intervals, smaller engines, and often more aggressive driving.

I imagine that if Toyota recommended a 9,000 mile change interval in the US as they do in the UK, many US owners would change the oil every 3,000 - 5,000 miles according to the recommendation of the guy paid to change the oil anyways. Perhaps Toyota recommends a 5w30 here because they figure its easier to recommend the optimal viscosity for our habitual oil change frequency than it is to get us to switch to the optimal viscosity for a new optimal oil change frequency?

The European ACEA oil specifications (written by car makers) are also more demanding than the American API specifications (written by oil companies). The ACEA standards are mulitiered and some oils meeting them are available in the US.

Can anyone share what oil Toyota recommends for the Prius in other countries?

 

Thicker oil may not always protect better. Thicker oil might be better for long intervals with conventional oil because that oil will shear down with extended use. I have seen no proof that 5w-20 oil is an inferior oil, based on viscosity. We will never solve that question because too many people have their own ideas, but lab results show that 5w-20 is working well. Police departments with their Ford Crown Vic's running 5w-20, with lots of idling time and generally tough conditions are doing just fine. These are large V8's with very tough conditions that are suffering no lubrication related failures, even up to 200k miles in service. Several departments are using MotorCraft 5w-20, a so called semi-synthetic and changing at 7.5 to 10k miles with good results.

I would like to hear from any Prius owners that are using 5w-20 oil.

 

Synthetic oil is one way to lessen, however slightly, one's use of petroleum. I avoid Mobil 1 because Exxon/Mobil is probably the most irresponsible (oil) company on the planet and THAT is a tough contest.
I saw this thread response from Bob Allen two years ago after I just changed my oil and switched to Mobile 1 synthetic oil.

My questions to those in the know:

1) Is there a responsible oil company that has a better environmental record than the others?
2) Is there any problem switching synthetics, Mobile 1 to Amsoil or Royal Purple?

 

O weight might give better mpg's