spark plug question
Thread Starter
Burning Brakes
Joined: Nov 2001
Posts: 1,163
Likes: 19
From: Not far from COTA
spark plug question
I just started changing the plugs/wires in my 2003 Z06
Took out AC 41-974, #12563707.
But, Chevy dealer sold me AC 41-985, #12571164
Anyone know what the difference is?
Can I use them without problem?
Car isn’t driven hard on a regular basis
Took out AC 41-974, #12563707.
But, Chevy dealer sold me AC 41-985, #12571164
Anyone know what the difference is?
Can I use them without problem?
Car isn’t driven hard on a regular basis
Safety Car
Joined: Jan 2001
Posts: 4,385
Likes: 689
From: Boise ID
The 41-985 is now what GM calls for. The gap also changed from .060 to .040. Below is from the service manual.
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.
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.
Thread Starter
Burning Brakes
Joined: Nov 2001
Posts: 1,163
Likes: 19
From: Not far from COTA
wow, thanks for the great answer
looks like my parts guy gave me the right stuff
would have been the first time he had messed up if they were wrong
I'd forgotten how helpful this forum is
been focusing on Miata stuff for the last year or so and haven't been on the forum much
looks like my parts guy gave me the right stuff
would have been the first time he had messed up if they were wrong
I'd forgotten how helpful this forum is
been focusing on Miata stuff for the last year or so and haven't been on the forum much
Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
Since we're on plugs. I bought my C5 new in 99 and it came with NGKTR55IX from the factory. At 30K miles I replaced them and installed the same plug. I drove 30K the first year. Just wondering is this still the recommended plug for the 99 C5? Thanks vettdvr
Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
My only concern with this plug is I pulled all 8 at 30,000 miles and found the iridium tip missing from 2 of the plugs. Where did it go?
Through the cylinder, valve, exhaust or burned off? I am concerned about material failure in the NGK. Granted this was back in 99 and they may have improved. It would be interesting to see what experience others have with this plug. Due to the failure of the tip is why I was wondering if there was a AC? plug
Doesn't mean the NGK's are bad I have a set running now. But still concerned about the failure.
Through the cylinder, valve, exhaust or burned off? I am concerned about material failure in the NGK. Granted this was back in 99 and they may have improved. It would be interesting to see what experience others have with this plug. Due to the failure of the tip is why I was wondering if there was a AC? plug
Doesn't mean the NGK's are bad I have a set running now. But still concerned about the failure.
Safety Car
Joined: Nov 2000
Posts: 4,419
Likes: 6
From: Arroyo Grande CA
To my knowlwedge all OEM plugs thru at least 2000, maybe longer, were Platinum plugs. These are the ones that may have had the Platinum pads missing from across the electrode. Gm changed to Iridium plugs around 2003?
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
And GM wasn't using NGK as OEM either. They were Denso.
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