Why would GM recommend AGAINST platinum spark plugs?

Dear Car Talk | Jul 01, 1995
Dear Tom and Ray:
Harold
TOM: Sure you can, Harold. GM didn't say the platinum tipped plugs would do any harm, they just said that they only recommend their own brand. And of course they only recommend their own brand. They make money when you buy their brand. If they could get away with it, they'd sell you "genuine" GM water for your cooling system and "genuine" GM air for your tires.
RAY: And GM is not alone. Most manufacturers tell you not to use anything but "genuine" or "original" (fill-in-the-blank) parts and fluids. And in general, this is bull-feathers. As long as the parts and fluids you use "meet or exceed OEM (original equipment manufacturer) specifications" for your car, they should be fine. And the packaging on the product should tell you whether that's the case.
TOM: The platinum tipped plugs simply last a lot longer than conventional plugs. And a lot of new cars--all of which are fuel injected--are using them these days. In fact, if you put platinum tipped spark plugs into an '87 Celebrity, I'll bet you 20 bucks the plugs outlast the car by at least 50,000 miles!
Harold
TOM: Sure you can, Harold. GM didn't say the platinum tipped plugs would do any harm, they just said that they only recommend their own brand. And of course they only recommend their own brand. They make money when you buy their brand. If they could get away with it, they'd sell you "genuine" GM water for your cooling system and "genuine" GM air for your tires.
RAY: And GM is not alone. Most manufacturers tell you not to use anything but "genuine" or "original" (fill-in-the-blank) parts and fluids. And in general, this is bull-feathers. As long as the parts and fluids you use "meet or exceed OEM (original equipment manufacturer) specifications" for your car, they should be fine. And the packaging on the product should tell you whether that's the case.
TOM: The platinum tipped plugs simply last a lot longer than conventional plugs. And a lot of new cars--all of which are fuel injected--are using them these days. In fact, if you put platinum tipped spark plugs into an '87 Celebrity, I'll bet you 20 bucks the plugs outlast the car by at least 50,000 miles!
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