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Have 2002 Deville DHS. By about 4000 on the odometer, noticed ping and knock. Lifters and cam sensor replaced and carbon cleaning done. Has consistently returned at between every 4,000 to 6,000 miles, and temporaily alleviated by another round of carbon cleaning. Using mainline regular gas and driving lots of highway miles (48,000+). After six months and a variety of explanations from Cadillac customer service (bad gas, switch to higher octane, it ain't so bad live with it), they now say the ping and knock is normal for the engine (because of undersized pistons starting in 2001) for first two minutes after cold start, and that it will not cause damage. No matter that mine pings/knocks without regard to time or temperature, and that the pinging/knocking disappear (at least to my ears) after carbon cleaning.

What's your experience with the problem and solution? I've always thought pinging bad, smooth and quiet good. Don't really look forward to pulling the cover and running the cleaner through five to six times a year. :bighead:
 

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'05 Expedition
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Yeah, I think I'd be pissed off, too.

I'm looking at 2001 & 2002 DeVilles as the #2 possibility for my next car. (of course, a '96 Fleetwood is my preference)

You've succeeded in scaring the crap out of me. I'll be listening very closely when I test drive one.
 

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The noise THEY are talking about IS normal. It's just piston noise that DOES disappear as the pistons swell and go from their oblong shape to a true round shape. The "ping" or detonation issue you speak of is a very real problem with the Northstars. We had the same problem with our cars and found that the lowest octane we could run was 89, or basically "Plus". Regular would NOT run properly and consistently caused detonation and carbon depositing which just aggrevated the detonation issue. We adopted a regular Top Engine Cleaning (carbon removal), and went back to Premium gas. Problem solved.
 

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Come to think of it, a few weeks ago when I was at a Cadillac dealership, one of the first things the Cadillac salesman told me was that you DO NOT run premium in a Northstar. It's specifically designed to run on 87 octane, and running anything higher might void the warranty.

LMAO! What an idiot!

See also, Sal's thread about what gas to run in his new Brougham...
 

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'05 Expedition
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I've finally resigned myself to the fact that I know more about cars in general than just about any car salesman.

And after all the research I've done in the past year, I know more about the Northstar system than Cadillac salesmen do.
 
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