2002 Tahoe LT, 5.3 (non Flex) Spark Plug Change

joechevy2 · July 17, 2012

Hi,

I have an old question that I need some clarification on.

.

I have just bought a set of Delco Iridium Professional Plugs (41-110) as replacements for the original plugs in Tahoe.The plugs I am replacing are the originals and they have 93,000 miles on them. I removed one plug and found the part number is --> AC Delco 12567759 / NGK PZTR5A-15.

Here is my question. I measured the gap on the original plug I removed and it was .060. The label on the radiator cowl under the hood specifies .060 gap. The GM shop manual specifies .060 gap. The plugs that I bought are gaped to .040. A note on the side of the box says "SET GAP PER VEHICLE SPECIFICATION (exceptions may apply)" My understanding is that there is a TSB saying to use the 41-110 plugs on my Tahoe gaped to .040. I am also aware the some reports say not to change the gap on iridium plugs.

Should I install the plugs as they stand at .040 or should I regap them to .060.

If I leave them at .040, will it impact my California Smog results?

Thank you for help. Sorry to rehash this since I see may posts and answers on this, but none were very recent. I decide to post to see if anyone had an newer information.

Regards

Joe

00Silverado4x4 · July 17, 2012

From my understanding GM has changed the gap required to .040". I guess GM decided the new plugs don't need the bigger gap. DO NOT regap those plugs, they don't take kindly to being adjusted, plus if you do and one of them messed up your out on your bum. Personally I would just install the plugs with the smaller gap and be done. If anything your smog check should come back better than ever with new plugs.

***DISCLAIMER***

This post contains no factual (provable) data, merely personal opinion from one GM nut to whomever may read this post.

***DISCLAIMER OVER***

txab · July 17, 2012

.040 is the new gap as suggested by GM. See the TSB shown below.

#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.

--------------------------------------------------------------------------------

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).

--------------------------------------------------------------------------------

• 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

nGAbear · July 17, 2012

My 01 Suburban falls under the same bulletin. I replaced the old .06 with .04 gaps and it is purring just fine.

I didn't replace them with NGKs and I should have... That's my only complaint.

00Silverado4x4 · July 17, 2012

.040 is the new gap as suggested by GM. See the TSB shown below.

#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.

--------------------------------------------------------------------------------

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).

--------------------------------------------------------------------------------

• 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

© 2008 General Motors Corporation. All rights reserved.

That's what I said....lol

joechevy2 · July 17, 2012

Everyone...Thank You for the feedback. I know what to do now.

Best Regards to All...Joe

Why do wish you used NGK?....Did the Delco's fall short?

My 01 Suburban falls under the same bulletin. I replaced the old .06 with .04 gaps and it is purring just fine.

I didn't replace them with NGKs and I should have... That's my only complaint.

XRMAN · July 20, 2012

I went back to NGK like the stock ones in my None Flex 2002 5.3 and I got 14.7 MPG running 89 Octane. was only getting 13.2 at best. Now that is none Highway driving.....

Chris · July 20, 2012

The new gaps are ca compliant. I just had my truck smogged with the new gaps

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nGAbear · July 20, 2012

Mine had the NGKs prior to my changing them. I wish I would have replaced them with NGKs (only with the new gap) so as to not introduce an additional variable and to better determine how she runs with the new gaps.