by Garrett McKinnon
VehicleMD Staff Writer
Internet article

By now, many people have heard the news. Ford Motor Company, one of the last holdouts of that old standby, the 3,000-mile oil change, recently relented and raised their recommended intervals for the confusing “special” operating conditions to 5,000 miles for all 2007 models. The company also raised its recommendation for “normal” driving (that is, jumping in the car and driving 20-plus miles at highway speeds, and only doing so once or twice per day — something that is decidedly not “normal”) to 7,500 miles.

That little development left only one major automaker that lists 3,000 miles in its service recommendations: Mitsubishi, which recommends 3,000 mile oil changes (but not filter changes, oddly enough) for “severe” driving. (Note that Subaru recommends an initial 3,000-mile “break-in” oil change for some of its 3.0L H6 engines; see sidebar for a complete list of modern oil change intervals.)

The news left us wondering, however, just where and when the old 3,000-mile interval came to pass. Quite a few of us grew up hearing little else, but what did automakers in days of yore really recommend? To find out, we consulted that vast bastion of information. You know, eBay.

More to the point, we searched high and low through the electronic hallways of that vast online auction house for old owners manuals. Very old. Antique, even. What we found surprised us.

Our first owners manual belonged to a 1967 Chevrolet pickup. Forty years ago, Chevrolet recommended an oil change every 60 days or 6,000 miles, whichever came first. Of course, that came with the caveat that vehicles used in “heavy-duty” operation involving “continuous stop-start or prolonged idling” should have oil changes every 2,500 to 3,500 miles. Oil filter changes were recommended every six months or 6,000 miles, unless two-quart elements were used. Those big boys had a recommended replacement interval of 8,000 miles.

An owners manual for 1968 Pontiacs (which included Tempest, Le Mans, GTO, Catalina, Executive, Bonneville, Grand Prix and Firebird models) contained similar intervals, though the 60-day interval had been stretched to four months. In cold temperatures and dusty conditions, Pontiac recommended an oil change every two months or 3,000 miles (though the company noted that operation in a dust storm necessitated an immediate oil and filter change).

The 1971 Chevrolet car owners manual again recommended oil changes every four months or 6,000 miles, while again adding the caveat that in cold weather, dusty conditions or when used for trailer pulling or commercial use that would cause extensive idling, the oil change interval should not exceed two months or 3,000 miles. Interestingly, by 1971 5W-30 motor oil had made an appearance in owners manuals, with Chevrolet recommending the oil for temperatures below 60° F; above that mark the General still recommended 10W-30, 10W-40, 20W-40 or SAE 20W motor oil.

In its 1973 Ford Bronco owners manual, Ford recommended an oil change every four months or 4,000 miles, but cautioned that operation in cold weather, driving short distances, extended idling, or low-speed operation could shorten that interval. Too, Ford wasn’t as certain about that new thin 5W-30, only recommending it for temperatures below freezing.

A Chevrolet truck owners manual from the same year still shows the same four-month/6,000-mile oil change interval for “normal” driving and a two-month/3,000-mile oil change interval for the previously mentioned dusty/cold/short-trip/high-speed/idling conditions. Plus, GM still noted that 5W-20 could be used in temperatures below 20° F.

By 1976, Ford had introduced three separate maintenance schedules: A, B and C. According to an owners manual from a 1976 Pinto (a collector’s item if anyone’s interested), the maintenance schedule that corresponded with a particular vehicle was identified by a decal on glove box door. Schedules A and B called for oil changes every five months or 5,000 miles, and filter changes every other oil change. “Severe Service Operation” for schedules A and B called for oil changes every two-and-a-half months or 2,500 miles, with filter changes every other oil change. Schedule C called for “normal” oil changes every four months or 6,000 miles, with “severe” conditions every two months or 3,000 miles. Oil filter changes were, again, recommended every other oil change. (One guess as to what interval the Pinto recommended.)

A 1977 Chevrolet owners manual recommended oil changes every 7,500 miles or 12 months, with filter changes every second oil change if mileage was the determining factor and every oil change if time was. Clear as mud, right? For vehicles operated in dusty conditions, trailer pulling, extensive idling and short-trip operation in freezing conditions, Chevrolet recommended oil change intervals of three months or 3,000 miles, the first instance we could find of what would eventually become the industry standard (if such a beast ever truly existed). Note that GM also recommended only using API SE engine oil, a far cry from today’s API SM standard.

The 1978 AMC owners manual we acquired (anyone remember the Pacer or Gremlin?) recommended oil changes every five months or 5,000 miles for four-cylinder engines and every seven months or 7,500 miles for six- and eight-cylinder engines. For “short-trip” driving (frequent trips of less than six miles), AMC recommended an oil change (no filter change) at even intervals between regularly scheduled oil and filter changes. Somewhat ironically, the company noted that oil consumption of up to one quart every 1,000 miles was not “excessive.” (Plus, the company, like GM, also recommended a 5W-20 motor oil for temperatures below 0° F.)

The oldest foreign owners manual we came across was for a 1979 Toyota pickup. Toyota called for oil and filter changes every six months or 7,500 miles, though the manual noted, “under severe driving conditions, more frequent maintenance is required.” No word on what those severe driving conditions might have been. Like many other automakers of the period, Toyota also recommended no fewer than eight grades of motor oil: SAE 30 for temperatures above 40° F; SAE 20 for temperatures between 10° F and 60° F; 20W-40 or 20W-50 for temperatures above 10° F; 10W-30, 10W-40 or 10W-50 for temperatures above minus-10° F; and 5W-30 for temperatures below 50° F.

A 1981 Pontiac Grand Prix owners manual recommended oil changes every 12 months or 7,500 miles for “normal service” and every three months or 3,000 miles for “severe service” that included driving in dusty areas, towing a trailer, frequent idling or short trips of four miles or less in freezing weather. Interestingly, the same manual recommended oil changes every 12 months or 5,000 miles (regardless of conditions) for the optional Oldsmobile-built 5.7L V8 diesel (remember those?).

The owners manual for a Datsun 310 compact built the same year recommended oil changes every six months or 7,500 miles, or every three months/3,000 miles in severe conditions defined as short distance driving, extensive idling or driving in dusty conditions. Dust/idling/short trips. A familiar refrain.

Ford touted its 1982 Escort as a “world car,” and the owners manual reflected a European-like oil change interval of 12 months or 7,500 miles (with filter changes every other oil change). The “Schedule B” applied to all vehicles with Ford’s 1.6L four-cylinder engine. For severe conditions that included idling, short trips, dusty conditions, trailer towing, cold temperatures (below 10° F) for more than 60 days and sustained high speed driving in hot weather above 90° F, Ford recommended oil change intervals of three months or 3,000 miles.

An owners manual for 1984 Oldsmobile vehicles again touts GM’s standby of 12 months/7,500 miles “normal” or three months/3,000 miles “severe.” Also, by this time manufacturers had begun limiting oil recommendations, as well. For 1984 Olds vehicles, GM recommended SAE 30 for temperatures above 40° F, 20W-20 for temperatures above 20° F, 15W-40 for temperatures above 10° F, 10W-30 for temperatures above 0° F and 5W-30 for temperatures below 60° F (except in Firenza and Omega models, which could use the thinner oil in temperatures below 100° F).

The 1980s brought us something akin to standardization of oil change intervals. Manuals from a 1986 Ford F-Series pickup, 1987 Mercury Sable, 1987 Pontiac 6000 and 1989 Chevrolet S-10 all recommend what had become a standard (at least for most domestic models) 12-month/7,500-mile or three-month/3,000-mile oil change interval. It is interesting to note that during this time, however, manufacturers began moving to 5W-30, which was the factory fill in both 1987 sedans and the ’89 pickup.

If digging through these piles of owners manuals showed us anything, it is that oil change intervals have never been simple. Different manufacturers have always recommended their own oil change interval, only attempting to match other intervals if they note a perceived disadvantage in the customer service arena. From the monthly intervals most common with vehicles in the 1960s to the willy-nilly days of the 1970s with their myriad interval recommendations to the almost standardized intervals of the late 1980s and beyond, automakers have always chosen their own path. Today, that path seems to involve extending intervals to some combination of 5,000/7,500 miles or beyond. (Although such a tactic doesn’t always work out; remember Toyota and Volkswagen rolling back oil changes to 5,000 miles — regardless of driving conditions — after being burned by oil gelling problems in some of their engines?)

Could the auto industry be returning to a situation similar to the 1970s, when an auto industry “standard” oil change interval was more myth than reality? Only time will tell. Now, anyone know someone who’s in the market for a stack of dusty old owners manuals?