Is there a change in plug gap?
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
Is there a change in plug gap?
I have been running the NGK iridium's 55ix since I bought the C5 new iin 99. The first set changed at 40,000 miles had lost 2 pucks. The gap in the owners manual was .060 and the replacement set were .060. Today I bought a new set of plugs but bought the AC Delco 41-110's which is the New delco part for the 99 C5. However they were gapped at .040. These are iridium plugs also and not to be hand set.
So what' the scoop. I installed them at the preset .040 vs trying to bend/open them to .060. The first thing I noticed was the engine was noticably smoother. This might just be replacing the worn NGK's which still were at .060 after 50,000 miles of driving.
So the question... What should the gap be for 99 C5.. .060 as in owners manual or .040 as in the new GM part ?
Thanks vettdvr
So what' the scoop. I installed them at the preset .040 vs trying to bend/open them to .060. The first thing I noticed was the engine was noticably smoother. This might just be replacing the worn NGK's which still were at .060 after 50,000 miles of driving.
So the question... What should the gap be for 99 C5.. .060 as in owners manual or .040 as in the new GM part ?
Thanks vettdvr
Tech Contributor
Joined: Jan 2007
Posts: 19,475
Likes: 1,171
From: Dyer, IN
I have been running the NGK iridium's 55ix since I bought the C5 new iin 99. The first set changed at 40,000 miles had lost 2 pucks. The gap in the owners manual was .060 and the replacement set were .060. Today I bought a new set of plugs but bought the AC Delco 41-110's which is the New delco part for the 99 C5. However they were gapped at .040. These are iridium plugs also and not to be hand set.
So what' the scoop. I installed them at the preset .040 vs trying to bend/open them to .060. The first thing I noticed was the engine was noticably smoother. This might just be replacing the worn NGK's which still were at .060 after 50,000 miles of driving.
So the question... What should the gap be for 99 C5.. .060 as in owners manual or .040 as in the new GM part ?
Thanks vettdvr
So what' the scoop. I installed them at the preset .040 vs trying to bend/open them to .060. The first thing I noticed was the engine was noticably smoother. This might just be replacing the worn NGK's which still were at .060 after 50,000 miles of driving.
So the question... What should the gap be for 99 C5.. .060 as in owners manual or .040 as in the new GM part ?
Thanks vettdvr
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
A most gracious thank you for your help.!
And posting of the tech service bulletin.
Tech Contributor
Joined: Jan 2007
Posts: 19,475
Likes: 1,171
From: Dyer, IN
Actually I did a search in the forum's but didn't search the tech bulletins. I can't list how many times under plug type / plug search items came up. I read quite a few and saw nothing specific on the gap.
A most gracious thank you for your help.!
And posting of the tech service bulletin.
A most gracious thank you for your help.!
And posting of the tech service bulletin.
