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First Spark Plug Change @ 75K Miles

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I need some advice on a first time plug change on my truck. Aside from busted knuckles, what are the challenges in changing the plugs in a 2002 5.3L Silverado. I'm a little confused on those metal heat shields surrounding the spark plugs. Do you remove them first, before you remove the plug wires? If so, how do you remove them? Are aftermarket wires preferred over the AC/Delco's? Are the correct replacment plugs AC Delco P/N 41-985? Thanks, GT

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The boots might be a bear to get off. I found that if I twisted them some it made it easier to pull the boots off. The metal heat shields come off with them. When you put them back on use some dielectric grease inside the boot for easy removal later on. The stock plug wires work great. No real advantage going aftermarket other than looks.


Here is some info on the plugs.


Spark Plug: Technical Service Bulletins Ignition System - New Spark Plug Type/Gapping

Bulletin No.: 03-06-04-060

Date: October 24, 2003



Information on New Spark Plugs and Gapping


2004 Buick Ranier

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 CMC Sierra

2000-2004 CMC Yukon, Yukon XL

2001-2004 CMC Yukon Denali, Yukon XL Denali

2002-2004 CMC Sierra Denali

2003-2004 CMC 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, LSI, LS6, LQ9, LQ4)

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 inches) when the spark plug is made. 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.

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41-110 replaces 41-985. Use a little anti-sieze on the plug threads. Heat shields pull off with a little effort. You may need to replace wires if you tear them up getting them off. I just changed my wires with the plugs, but I did mine at a higher mileage. Iridium plugs are good to at least 100k miles

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Not hard at all, I changed mine a few years back on my 02 Sierra. I ditched the heat shields and went with a set of Taylor wires that had a much higher heat resistance than stock. Those and the A/C Delco's and you'll be set. No cut or broken knuckles if you take your time. Good luck!

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I think I had to use a U-joint on my ratchet for the rear plug closest to the firewall. After you pull off the wires just slide the heat shield off the old wires and put them on the new ones. I would recommend changing wires. Just seems like the smart thing to do.

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