Spark Plug Gap...

black00chev · June 30, 2008

Just picked up some fresh ACDelco Iridium plugs for the silverado and just curious as to what you guys are gapping them to... On the box it says gap to manufacturer specs but just wondering if you guys are doing anything different with any advantages.

MS3DALE · June 30, 2008

This might help you.....

Service Information 2000 Chevrolet Chevy K Silverado - 4WD | Sierra, Silverado, Suburban, Tahoe, Yukon (VIN C/K) Service Manual | Document ID: 1903277

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#03-06-04-060A: Information on New Spark Plugs and Gapping - (Feb 12, 2007)

Subject: Information on New Spark Plugs and Gapping

Models: 2004 Buick Rainier

2002-2004 Cadillac Escalade, Escalade EXT

2003-2004 Cadillac Escalade ESV

2004 Cadillac CTS-V

1997-2004 Chevrolet Corvette

1998-2002 Chevrolet Camaro

1999-2004 Chevrolet Silverado

2000-2004 Chevrolet Suburban, Tahoe

2002-2004 Chevrolet Avalanche

2003-2004 Chevrolet Express, TrailBlazer

1999-2004 GMC Sierra

2000-2004 GMC Yukon, Yukon XL

2001-2004 GMC Yukon Denali, Yukon XL Denali

2002-2004 GMC Sierra Denali

2003-2004 GMC Envoy XL

1998-2002 Pontiac Firebird

2004 Pontiac GTO

2003-2004 HUMMER H2

with 4.8L, 5.3L, 5.7L or 6.0L V-8 Engine (VINs V, P, T, Z, G, S, N, U -- RPOs LR4, LM4, LM7, L59, LS1, LS6, LQ9, LQ4)

Attention: Please disregard the Set Gap Per Vehicle Specification statement on the side of an ACDelco® Iridium Spark Plug Box. The statement will be removed from the boxes in the future.

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This bulletin is being revised to bring attention to the Set Gap Per Vehicle Specification on the ACDelco® Iridium Spark Plug Boxes. Please discard Corporate Bulletin Number 03-06-04-060 (Section 06 -- Engine/Propulsion System).

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• A new spark plug has been released for use in the above vehicles. The new spark plug has an Iridium tip instead of the current Platinum tip. Due to the different tip design, the gap of the spark plug has also changed.

• The new spark plug, P/N 12571164 with AC Delco P/N 41-985, is gapped to 1.01 mm (0.040 in) when the spark plug is made.

Notice: The spark plug gap is set during manufacturing and should not be changed or damage to the spark plug may result. Any new spark plug found to not be properly gapped should not be used.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

black00chev · June 30, 2008

Hey thanks Rich... So check that they are at .040 and if not don't use, easy enough.

black00chev · June 30, 2008

Also forgot to ask if anyone else wants to chime in... What, if any, spec are you tightening plugs to? Is there a specified torque or just go hand snug then 1/8-1/4 turn?

thanks.

merlin5577 · June 30, 2008

Also forgot to ask if anyone else wants to chime in... What, if any, spec are you tightening plugs to? Is there a specified torque or just go hand snug then 1/8-1/4 turn?

thanks.

I believe the spec is around 18 ft-lbs, but your owners manual will list all the specs.

MS3DALE · June 30, 2008

From the service manual...

"For new aluminum heads tighten the spark plugs to 20 N·m (15 lb ft)."

black00chev · June 30, 2008

well unfortunatly i dont have a 1/4-3/8 adapter for my 1/4" torque wrench so i just ran them down till they bottomed out and took her out for a test drive and she purrs just fine.