The SAE (Society of Automotive Engineers) grade number indicates the viscosity of the engine oil, and thus its ability to lubricate at a given temperature. The lower the SAE grade number, the lighter the oil; the lower the viscosity, the easier it is to crank the engine in cold weather.
The API (American Petroleum Institute) designation indicates the classification of engine oil for use under given operating conditions. Only oils designated for use "Service SH," or latest superceding grade should be used. Oils of the SH type perform a variety of functions inside the engine in addition to the basic function as a lubricant. Through a balanced system of metallic detergents and polymeric dispersants, the oil prevents the formation of high and low temperature deposits, and also keeps sludge and dirt particles in suspension. Acids, particularly sulfuric acid, as well as other byproducts of combustion, are neutralized. Both the SAE grade number and the API designation can be found on the quart of oil.
Oil viscosities should be chosen from those oils recommended for the lowest anticipated temperatures during the oil change interval.
Multi-viscosity oils offer the important advantage of being adaptable to temperature extremes. They allow easy starting at low temperatures, yet give good protection at high speeds and engine temperatures. This is a decided advantage in changeable climates or in long distance touring.
OIL LEVEL CHECK
The engine oil level should be checked at every fuel stop, or once a week, whichever occurs more regularly. The best time to check is when the engine is warm, although checking immediately after the engine has been shut off will result in an inaccurate reading, since it takes a few minutes for all of the oil to drain back down into the crankcase. If the engine is cold, the engine should not be run before the level is checked. The oil level is checked by means of a dipstick, located at the front of the engine compartment:
- If the engine is warm, it should be allowed to sit for a few minutes after being shut off to allow the oil to drain down into the oil pan. The car should be parked on a level surface.
- Pull the dipstick out from its holder, wipe it clean with a rag, and reinsert it firmly. Be sure it is pushed all the way home, or the reading you're about to take will be incorrect.
- Pull the dipstick again and hold it horizontally to prevent the oil from running. The dipstick on the four cylinder engine is marked with "Add" and "Full" lines. The V6 engine dipstick is marked "Add 1 Qt." and "Full." The oil level should be above the "Add" line.
- Reinstall the dipstick.
If oil is needed, it is added through the capped opening in the engine valve cover. One quart of oil will raise the level from "Add" to "Full". Only oils labeled "SH" should be used; select a viscosity that will be compatible with the temperatures expected until the next drain interval. See the "Oil and Fuel Recommendations" information later in this guide if you are not sure what type of oil to use. Check the oil level again after any additions. Be careful not to overfill, which will lead to leakage and seal damage.
CHANGING OIL & FILTER
If you purchased your X-Body car new, the engine oil and filter should be changed at the first 7,500 miles or 12 months (whichever comes first), and every 7,500 miles or 12 months thereafter. You should make it a practice to change the oil filter at every oil change; otherwise, a quart of dirty oil remains in the engine every other time the oil is changed. The change interval should be halved when the car is driven under severe conditions, such as in extremely dusty weather, or when the car is used for trailer towing, prolonged high speed driving, or repeated short trips in freezing weather.
- Drive the car until the engine is at normal operating temperature. A run to the parts store for oil and a filter should accomplish this. If the engine is not hot when the oil is changed, most of the acids and contaminants will remain inside the engine.
- Shut off the engine, and slide a pan of at least six quarts capacity under the oil pan. Throw-away aluminum roasting pans can be used for this.
- Remove the drain plug from the engine oil pan, after wiping the plug area clean. The drain plug is the bolt inserted at an angle into the lowest point of the oil pan.
- The oil from the engine will be HOT. It will probably not be possible to hold onto the drain plug. You may have to let it fall into the pan and fish it out later. Allow all the oil to drain completely. This will take a few minutes.
- Wipe off the drain plug, removing any traces of metal particles. Pay particular attention to the threads. Replace it, and tighten it snugly.
- The oil filter for the V6 engine is right up front, just behind the radiator. The four cylinder oil filter is at the back of the engine. It is impossible to reach from above, and almost as inaccessible from below. It may be easiest to remove the right front wheel and reach through the fender opening to get at the four cylinder oil filter. Use an oil filter strap wrench to loosen the oil filter; these are available at auto parts stores. It is recommended that you purchase one with as thin a strap as possible, to get into tight areas. Place the drain pan on the ground, under the filter. Unscrew and discard the old filter. It will be VERY HOT, so be careful.
- If the oil filter is on so tightly that it collapses under pressure from the wrench, drive a long punch or a nail through it, across the diameter and as close to the base as possible, and use this as a lever to unscrew it. Make sure you are turning it counterclockwise.
- Clean off the oil filter mounting surface with a rag. Apply a thin film of clean engine oil to the filter gasket.
- Screw the filter on by hand until the gasket makes contact. Then tighten it by hand an additional 1 / 2 to 3 / 4 of a turn. Do not overtighten.
- Remove the filler cap on the rocker (valve) cover, after wiping the area clean.
- Add the correct number of quarts of oil specified in the "Capacities" chart. If you don't have an oil can spout, you will need a funnel. Be certain you do not overfill the engine, which can cause serious damage. Replace the cap.
- Check the oil level on the dipstick. It is normal for the level to be a bit above the full mark. Start the engine and allow it to idle for a few minutes.
Check around the filter and drain plug for any leaks.
- Shut off the engine, allow the oil to drain for a minute, and check the oil level.
After completing this job, you will have several quarts of filthy oil to dispose of. The best thing to do with it is to funnel it into old plastic milk containers or bleach bottles. Then, you can pour it into the recycling barrel at the gas station (if you're on good terms with the attendant).