Auto-Rx Customers Questions & Answers

You may have noticed that there is a page on the http://www.auto-rx.com/ website entitled Choosing a Motor Oil for Use with Auto-Rx.  Simply put we recommend you use an inexpensive conventional motor oil during your cleaning applications for two reasons.  One it saves you money and two it allows Auto-Rx^® Plus to work more effectively. 

Let's discuss for a moment the various motor specifications.  Twenty years ago, choosing the oil for your car was simple. All you needed to know was the viscosity 5W-30 or 10W-30, for example, and you could get a few bottles at the local auto parts store. But this simplicity is starting to go away.

General Motors' transition to a new oil specification for all its 2011 and newer vehicles brought new attention to the issue of manufacturer oil specifications. GM isn't the first to require such a specification, but its move signals a change in the car-maintenance landscape.

The oil inside a modern engine might look just like it did a decade ago, but it actually is far more advanced. The American Petroleum Institute (API) and the International Lubricants Standardization and Approval Committee ( ILSAC) have set the standards for oil for the past 65 years and have changed the specifications roughly every five years. Oil needs to change to meet increasing emissions regulations, offer better protection against sludge and improve fuel economy.

The API and ILSAC standards are the baseline, automakers are free to improve upon the standards as long as they meet the minimum requirements. This manufacturer standard is more common among the German automakers, thanks to more stringent European oil specifications. Rather than have numerous blends for different regions, each automaker created one specification for its vehicles. They have brought those standards to the U.S., as Audi, BMW, Mercedes-Benz and Volkswagen all have their own oil formulations.

Most American and Japanese automakers have tended to stick with the API guidelines. This means that they recommend any oil with the API "starburst" or "donut" symbol on its label.  GM distanced itself from the API guidelines with the introduction of Dexos. According to GM, the Dexos oil specification will decrease harmful piston deposits by up to 28 percent and improve fuel efficiency by up to 0.3 percent compared to the older ILSAC GF-4 specifications.

GM licenses the Dexos certification to motor oil manufacturers that can then choose to offer a full-synthetic variation, as long as it meets the requirements.

As manufacturer oil specifications become more common, the auto industry moves farther away from conventional oil and toward synthetic blends or fully synthetic oil. While these newer oils offer better protection and longer intervals between oil changes, they also have a higher price tag.

Not all cars require a manufacturer-specified oil. They do have a recommended viscosity, such as 0W-20, however. Check the owner's manual for any mention of a required brand or specification. If the manual doesn't name one you are free to shop around for the best deal on motor oil.  Just make sure it's the correct viscosity.

Auto-Rx^® Plus is compatible with all 4-stroke motor oils. However, for the best results, conventional motor oils work best. The normal cleaning and rinse phases of an Auto-Rx^® Plus cleaning application are only for a relatively short duration of 3,000 miles. In nearly all cases, conventional oil will provide the same level of lubrication as would an expensive full-synthetic motor oil for such a short duration. Auto-Rx^® Plus is more active in simple conventional oils.

If you would prefer to run Auto-Rx^® Plus with a full-synthetic or semi-synthetic oil, then merely increase the cleaning time to 4,500 miles.  If you are using Auto-Rx^® Plus to solve a rotary seal leak in a motor, using conventional oil is a must for both the cleaning and rinsing phases.  For heavily sludged motors, we also highly recommend running conventional oil for cleaning and rinsing. We recommend that you do not run oils badged as high mileage for the best cleaning and rinse results in heavily soiled motors or those with seal leak issues.

What oil brands do we recommend?  Unless you want to use a major oil brand the house brands of retailers such as Walmart, AutoZone, Oreilly, NAPA, etc. are an excellent choice for Auto-Rx^® Plus applications.
Some name brand names oil to consider are:

• Shell Rotella T
• Castrol GTX
• Pennzoil in the yellow bottle
• Pennzoil (Group III) Platinum
• Mobil Super 5000
• Conoco Phillips
• Trop Arctic

Our Advice? Dont waste money on expensive oil designed to run longer intervals. Auto-Rx^® Plus generally works best with the least expensive motor oil available. Choose an oil in the proper weight and viscosity that meets the manufacturer's specifications.   (Reference source for motor oil trends: Edmunds.com)