99 Sierra 5.3l Spark Plugs

[scott0303]

Guys, Im going to replace my plugs and wires soon. I have 130k miles on the 5.3l which I have owned since about 90k miles. I pulled a plug last week just to see what was in there. It was an ACDelco plug. My guess it was the original. A guy I work with has a 2000 Silverado with the 5.3l. He changed his plugs and was complaining about having to use iridium plugs. Anybody know if the AC plugs that were original to the truck are iridium? I didnt write down a part number but check it again tomorrow. What are guys with same engine putting back in theirs? Thanks

[txab]

Your truck probably came with either platinum or double platinum plugs. You can replace the plugs with whatever you please. Platinum, double platinum or Iridium. All are listed as viable replacements. Each step up the price ladder is an increase in plug life.

[landmine]

I've got an 04 Sierra with the 5.3. I went back with the ac delco iridiums and delco wires. Haven't had a single problem.

[jro909]

+1 for ac delcos

[pistonslap]

Guys, Im going to replace my plugs and wires soon. I have 130k miles on the 5.3l which I have owned since about 90k miles. I pulled a plug last week just to see what was in there. It was an ACDelco plug. My guess it was the original. A guy I work with has a 2000 Silverado with the 5.3l. He changed his plugs and was complaining about having to use iridium plugs. Anybody know if the AC plugs that were original to the truck are iridium? I didnt write down a part number but check it again tomorrow. What are guys with same engine putting back in theirs? Thanks

 

Remember to check what the gap is supposed to be if you decide to use irdium plugs. I can't recall the details,but GM issued a bulletin about changing the Gap when using iridium plugs.

[txab]

.040"

[Black02Silverado]

The gap should be preset by the factory when you buy them. Just check to make sure they are. There is a thread on here about that and if the gap is not set at .040 then you should take them back to the store. You are not suppose to try and regap them.

[brandon_guzzo]

I just did mine in my 2000 silverado. You have Platinum 0.060 in there right now the new ones recommended by GM is Iridium tip pre-gapped at 0.040

[desrtrat]

Subject: Information on New Spark Plugs and Gapping #03-06-04-060 - (10/24/2003)

 

 

 

Models: 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 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)

 

 

 

 

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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 1.01mm (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.

[jon.jensen2]

I have worked on the GM Gen III though VI small blocks for a number of years now and I can personally tell you from GM tech bulletins, training videos, personal experience, and through the experiences of others, you will not go wrong with the AC Delco Iridium plugs. They are a bit pricey, but no service is required for 100,000 miles on those. As far as the plug wires go, that is a different story. While the AC Delco plug wires are factory replacements and will do a perfect job delivering all the volts you need, the Bosch replacement plug wires will also provide an excellent spark and longevity for the price. I currently am running AC Delco Iridiums with Bosch plugs on my truck and I have not had one single issue, misfire, or hickup. Hope this helps you along the way.

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Autolite platinums gaped at .050 here. Runs just fine. If I do it again, I'm going with NGK t55s gaped at.055.