Posted by Gerry Tandberg on October 13, 1997 at 17:16:38:
In Reply to: Re: Dumb Questions posted by patrick on October 12, 1997 at 20:38:45:
Gerry...I agree with Patrick's comments. Great common sense answer's, especially those regarding detergent/non-detergent oil. I’m NOT a lubrication engineer, but my father was, so here’s my two cents worth.
Non detergent oils have no place in road vehicles. By all means use a multigrade motor oil, but only if you are reasonably sure the your engine is clean of gross residue (sludge). The result of previous poor maintenance (extended drain intervals), the use of non-detergent or poor detergent oil may have left large quantities of sludge deposits all over your engine. Any attempt to remove this sludge with diesel fuel, ATF, or any commercial cleaning additive w/o a tear down will result in everything washing to the sump of the oil pan. That is where the oil pickup is located. Enough sludge in the pan will plug the screen of the oil pickup resulting in oil starvation.
Living example; 1980 V8 station wagon with 100,000 miles. The original owner changed oil as recommended by the manufacture, every 6000 miles. (Poor interpertation on owners part) He used a leading brand of 10-30 oil advertised by a "famous golf pro". Later he sold to someone who preferred a different (superor) brand of 10-30 motor oil. After an oil change, and less than 2000 miles on a cross country trip, the engine seized. After dismantelement we found the oil pickup was solidly plugged with sludge. The engine internals were heavely sludged. The superior brand of 10-30 oil had been doing its job. No way of knowing how long this engine would have lasted if oil advertised by "famous golf pro" had continued to be used. Some would blame the superior oil as the culprit. What do you think? Moral of story is start with good detergent oil in new, rebuilt, or clean engines, change every 3000 miles, and stay away from oil advertised by "famous golf pro’s". I’ve got more examples but this was a classic.
A good grade of oil has many properties and does many things, i.e.; exhibits low pour characteristic, low carbon residue, good oiliness, high film strength, high resistance to oxidation, anti corrosion, anti foam, high dispersion, high detergent, and holds dirty particles in suspension. (Thats so you can drain the ugly stuff out) The majority of the oils available to us have these features...some better than others. Racing oils are for racing and have better oiliness and film strength characteristics, but less detergent additives. Racers change oil VERY frequenly. Use common sense here.
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