I have been using mineral motor oil in my Nissan 350Z for the past 2 years. I just switched over to semi-synthetic oil. Is there any concern in switching over from mineral to synthetic oil after this period of time? Can I switch back to mineral oil?

I don't forsee any problems, you can go back to mineral oil but if I were you, I would take full advantage of enhanced protection offered by good synthetics.

quote:

Originally posted by Danz:
You might check ou this site...it's Nissa recomending synthetic oil.

http://www.nissan.com.sg/service/plans.cfm?go=fasflo

@Nissan350Z: can you send this one to National Customer Affairs and see what comes as their reply now?

General Motors is now recommending fuel additives. Just a few years ago they said they don't recommend them and even said they would harm your engine.

Here it is straight from the horse's mouth

"Additives: To provide cleaner air, all gasolines in the United States are now required to contain additives that will help prevent engine and fuel system deposits from forming, allowing your emission control system to work properly. In most cases, you should not have to add anything to your fuel. However, some gasolines contain only minimum amount of additive required to meet U.S. Environmental Protection Agency regulations. To help keep fuel injectors and intake valves clean, or if your vehicle experiences problems due to dirty injectors or valves, look for gasoline that is advertised as TOP TIER Detergent Gasoline. Also, your GM dealer has additives that will help correct and prevent most deposit related problems.

Gasolines containing oxygenates, such as ethers and ethanol, and reformulated gasolines may be available in your area. General Motors recommends that you use these gasolines if they comply with the specifications described earlier. However, E85 (85% ethanol) and other fuels containing more than 10% ethanol must not be used in vehicles that were not designed for those fuels."

quote:

Originally posted by AlanCambel:
General Motors is now recommending fuel additives."...

You are not mixing fuel and oil additives?

quote:

Originally posted by Djordan:

quote:

Originally posted by AlanCambel:
General Motors is now recommending fuel additives."...

You are not mixing fuel and oil additives?

The point I was trying to make was that OEM manufactures often times don't recommend things because they don't have extensive testing themselves. To cover themselves they will often say "The use of additional engine oil additives, in and of themselves, will not automatically void an engine warranty. But we do not endorse the use of any oil additive" They say this because they don't want to spend $500,000 to test if an additive has passed the oil warranty test. They also don't wont their cars to last any longer than they are engineered for. There is a conflict of interest here.

In this case GM's cars are not running well due to low quality fuel. GM now has a reason to recommend a product because they are recieving customer complaints regarding engine performance. GM in the past said they do not endorse fuel additives . Fuel quality has been poor for years (toptiergas.com). So what they recommend is not ALWAYS the best for your car.

Most of the time it probably is.

At least it's a good thing GM start working on the enormous amount of CO2 the US releases into our sky!