GMC Sierra 1500 How often should I change my spark plug wires?

[Brenden Burnham]

I had one spark plug go bad and just replaced the one.  All is good but plan on changing the other 7 spark plugs.  Right now runs very good nice clean idle but do you feel I should change all the wires while I am at it?  I am sure most will say yes but is there a good reason to do so?  Do you all notice the wires failing at all?

[shakenfake]

I would just replace them all if you have never done it before. They just age and go through hot and cold cycles causing them to wear out. Just a wear item.

[Brenden Burnham]

6 minutes ago, shakenfake said:

I would just replace them all if you have never done it before. They just age and go through hot and cold cycles causing them to wear out. Just a wear item.

Thanks and yeah I agree.  

[Jworks]

I think the manual says after 100k.  I didn't change my plugs and wires until 135k and I didn't notice any change in mileage, so $ spent, and no benefit for me.  Since you had a plug go bad I'd probably change the others like you're planning to do.  I don't know (based on my experience) whether I'd do the wires again since I noticed no difference at all in mileage.  How many miles you got on the wires?  Do they "feel" good [not hard]?  You can change wires out later if you wish.  I'd say since you're engine is still running fine go by how many miles are on them and how they "feel".

[KARNUT]

When my 04 Z-71 was approaching 100K miles I asked a friend who happened to own a auto shop about changing my plugs. Knowing I drive about 50K miles a year he said if the light comes on change them. At 150k my son got the truck we did the transmission and antifreeze according to the manual. At 180K we traded it in same plugs. The only vehicle I put plugs in the last 5 years was my 92 Chevy truck after having it 12 years. I’m amazed at the advancement in the auto industry as far as oil, plugs, wires etc. My newest vehicle is approaching 7 years old. No flushes or fancy additives or anything done early for (longevity). I run my tire pressure for comfort. My oil at normal change intervals. Rotate my tires every 10K miles and never done an alignment. My brakes go close to 100K miles as well as my tires. Some people on here sure waste lots of money or are slaves to their vehicles. If a vehicle requires special maintenance to reach 150-200K it’s normal life, it’s a automotive failure.

[shakenfake]

Now that right there is the truest statement I have ever read on this damn site

[Brenden Burnham]

2 hours ago, Jworks said:

I think the manual says after 100k.  I didn't change my plugs and wires until 135k and I didn't notice any change in mileage, so $ spent, and no benefit for me.  Since you had a plug go bad I'd probably change the others like you're planning to do.  I don't know (based on my experience) whether I'd do the wires again since I noticed no difference at all in mileage.  How many miles you got on the wires?  Do they "feel" good [not hard]?  You can change wires out later if you wish.  I'd say since you're engine is still running fine go by how many miles are on them and how they "feel".

Not sure purchased the truck(2000 Sierra 1500) about 6 months ago.  The one plug that went bad after looking at the tip had broke and was for sure corroded so figure is a good idea to do all and due to the bad condition of the bad plug assume has not been done for a VERY long time.  

[Brenden Burnham]

2 hours ago, KARNUT said:

When my 04 Z-71 was approaching 100K miles I asked a friend who happened to own a auto shop about changing my plugs. Knowing I drive about 50K miles a year he said if the light comes on change them. At 150k my son got the truck we did the transmission and antifreeze according to the manual. At 180K we traded it in same plugs. The only vehicle I put plugs in the last 5 years was my 92 Chevy truck after having it 12 years. I’m amazed at the advancement in the auto industry as far as oil, plugs, wires etc. My newest vehicle is approaching 7 years old. No flushes or fancy additives or anything done early for (longevity). I run my tire pressure for comfort. My oil at normal change intervals. Rotate my tires every 10K miles and never done an alignment. My brakes go close to 100K miles as well as my tires. Some people on here sure waste lots of money or are slaves to their vehicles. If a vehicle requires special maintenance to reach 150-200K it’s normal life, it’s a automotive failure.

Very well said.  My truck does have a LOT of miles(270,000) and not knowing exactly was done prior I am a little on the cautious side so really if I am doing something I think my thinking is right go the extra mile assuming it wasnt done at least in a VERY long time.  I am very keen on keeping up with the fluids, oil change, etc on a vehicle especially one that has a lot of miles.  Recently had to replace bad idler pulley(bearings locked up)(causing damaged belt), and the recent EGR Valve that had gone bad.  The truck drives very good.

[KARNUT]

34 minutes ago, Brenden Burnham said:

Very well said.  My truck does have a LOT of miles(270,000) and not knowing exactly was done prior I am a little on the cautious side so really if I am doing something I think my thinking is right go the extra mile assuming it wasnt done at least in a VERY long time.  I am very keen on keeping up with the fluids, oil change, etc on a vehicle especially one that has a lot of miles.  Recently had to replace bad idler pulley(bearings locked up)(causing damaged belt), and the recent EGR Valve that had gone bad.  The truck drives very good.

My Avalanche is going on two years with me at 172K miles on it. It’s perfect for me.

[Supreme Pizza]

Just by default, when I buy a vehicle - I replace the spark plugs, wires, PCV air filter, fuel filter, run some injector cleaner, etc. This ensures that all the basic reliability items are in order, and also allows me to do any future diagnostics more easily. Once that's done, I will probably never have to replace the plugs again. I usually don't put more than maybe 75K miles on a rig before I upgrade to a newer model. Another reason that I do this is because sometimes the previous owner had installed the wrong plugs or other parts. The most recent vehicle that I bought did not require this stuff though. The previous owner had left receipts for $11,400 worth of automotive repair receipts in the glove box that were less than 2 years old. They dumped that much money into the rig, and then an AFM lifter failed. I wound up buying the rig for $2,950 and fixed it for a few hundred bucks and some elbow grease. Yahoo. Anyway, all that stuff aside, I would replace all the spark plugs if you have never done it before. If the plugs are fairly new, I would pull one or two of the other plugs to check the condition and make sure they are the correct type. If the other plugs are the correct type and in good condition then I would ...... Probably replace them anyway - because I like replacing spark plugs on my rigs. But if money is an issue at all - only replace them if there is a good reason to do so.

 

   

[Brenden Burnham]

23 hours ago, Supreme Pizza said:

Just by default, when I buy a vehicle - I replace the spark plugs, wires, PCV air filter, fuel filter, run some injector cleaner, etc. This ensures that all the basic reliability items are in order, and also allows me to do any future diagnostics more easily. Once that's done, I will probably never have to replace the plugs again. I usually don't put more than maybe 75K miles on a rig before I upgrade to a newer model. Another reason that I do this is because sometimes the previous owner had installed the wrong plugs or other parts. The most recent vehicle that I bought did not require this stuff though. The previous owner had left receipts for $11,400 worth of automotive repair receipts in the glove box that were less than 2 years old. They dumped that much money into the rig, and then an AFM lifter failed. I wound up buying the rig for $2,950 and fixed it for a few hundred bucks and some elbow grease. Yahoo. Anyway, all that stuff aside, I would replace all the spark plugs if you have never done it before. If the plugs are fairly new, I would pull one or two of the other plugs to check the condition and make sure they are the correct type. If the other plugs are the correct type and in good condition then I would ...... Probably replace them anyway - because I like replacing spark plugs on my rigs. But if money is an issue at all - only replace them if there is a good reason to do so.

 

   

It is funny that you showed a pic if that plug as I ran into the same thing just now after replacing number 6 it had broke, luckily was still able to remove.  Crisis adverted.  Am glad I replaced the plugs the old ones were pretty bad and they were iridium and gapped at .060.  As you may be aware the bulletin came out later that they had changed it to be .040 gap.  

 

What sucks is the wires I got even though showed was suppose to fit my GMC they were about .5 inches too short.  "ACDelco Wireset 9748GG"  Those showing suppose to be able to fit but nope.  Anyway reused the old ones as after inspection all seem good and well they are also ACDelco wires.  Idle does seem smoother with the new plugs am sure the old plugs and also the .6 gap had to do with the not as smooth idle.  

 

 

Edited December 16, 2021 by Brenden Burnham

[Brenden Burnham]

And I ended up going with the Bosch Platinum Spark Plug 6704 which are pre-gapped.  They are pre-gapped to .040 in case any are wondering. 

Edited December 16, 2021 by Brenden Burnham

[txab]

Gaps were .060 changed to .040, the correct way to show the measurement

[txab]

Just now, Brenden Burnham said:

And I ended up going with the Bosch Platinum Spark Plug 6704 which are pre-gapped.  They are pre-gapped to .4 in case any are wondering. 

You may end up regretting that choice later on, hopefully not. Bosch and a few other aftermarket plugs haven't always performed well. AC Delco, NGK, or Denso. All are OEM

[Brenden Burnham]

1 minute ago, txab said:

Gaps were .060 changed to .040, the correct way to show the measurement

Yes and the old plugs were .060 and the new ones pre-gapped to .040(Sorry left out a 0 in previous post).