How to Mix Synthetic Oil with Non Synthetic Oil
With the introduction of synthetic oils, synthetic oil blends and various other oil additives heralded with confusing, and sometimes erroneous ad campaigns, it is hard for the average consumer to know what is what in the engine oil world. However, the facts are not nearly as confusing as the misinformation and hype floating about. Synthetic oil is a man-made improvement of standard oil, but the two can be mixed with no ill effects as long as a few common sense measures are taken first.
Things You'll Need:
- Synthetic oil
- Non-synthetic oil
- Purchase the same brand, if possible, and same weight oil in non-synthetic and synthetic. If you plan to do several oil changes, it is probably best to purchase a case of each to save a few cents.
- Drain your oil into a drop pan and replace your oil filter as you normally would for an oil change. Reinstall the drain plug.
- Pour equal amounts of both synthetic and non-synthetic oils into the oil filler neck. You will need to make sure they are both the same weight, as you do not ever want to mix weights (i.e. do not mix a 10w30 standard oil with a 5w20 synthetic oil). If your oil fill cap does not say what weight you should use, check the dipstick. If it is not embossed on the dipstick, check the owner's manual. If all else fails, call your dealer for oil weight specifications.
Tips & Warnings
- Do not worry about mixing the two oils. Synthetic blends that many repair facilities use, and auto parts stores sell in quarts and gallons, are nothing more than a 50/50 mixture of synthetic and non-synthetic oil. It is advisable not to mix brands, but doing so once in awhile will not have any long term ill effects on your vehicle.
- You can change from full standard oil to full synthetic oil and back again with no ill effects on the engine, unless your vehicle's specific owner's manual states you should only run full synthetic. However, this is usually only the case with sports cars, such as Corvettes.