For 97-04 C5`s GM recommends 2 types of plugs:
1. AC Delco Iridium part # 41-985
2. AC Delco Rapid Fire part# 12

By mistake I`ve installed AC Delco Platinum part # 41-993.
Since 99 GM does not use platinums in Corvettes.

I have an 98 and after installation car runs great, however, I thought gas mileage was affected (can`t verify it accurately thou).
What is to expect from these plugs?...loss of performance, loss of gas mileage or?...is this somehow going to have consequences on the life of the engine, parts?

I`m thinking to pulling them out on Monday and shelling another $230 in parts and labor

What would you do?

 

You need to find a forum member in your area to help you with the plug change. I'm sure someone would be willing to help you out if you supply beer and pizza!

 

I`m willing to pay just to regain my sanity

 

Im at Camp Pendleton, CA how far away are you? Just PM me if your not to far we will set something up.

 

Im a lil` far from you, thanx anyways!

 

ttt

 

I went on to Jegs and ordered the Iridium plugs and MSD plug wires for a 2000 Corvette I have had absolutly no problems with a mild agressive set up.

 

Ok, first of all, GM does not recommend both platinum and iridium plugs for C5's for some years now. If you go to the dealership part counter, you will get iridiums as replacements. Since your year C5 did come from the factory with platinum plugs, there is absolutely no reason, that they will in any way harm your engine, or reduce it's life in any way. You have a stock car, so performance is not a concern.

In the words of Forrest Gump...."that's all I have to say about that"

 

Dude... Just leave them in there.. you will be fine.. All a spark plug does is produce a spark, leading to a controled explosion in the combustion chamber. Its ridiculous to even get worried over such a thing.

 

Agreed, however every plug has a certain heat range....the problem in my case is NOT that the plug is platinum and is not iridium but because the plug I have in my car is NOT used in this type of engine......ac delco webside has a list of GM engines that fit this plug ( part # 41-993 the one I have installed in my car ) and C5 corvette is NOT in there!
For the part 91-985( Iridiums) C5 IS ON THE LIST!
Isn`t there a reason why c5`s and are most compatible only with few plugs?.....
In may case Yes PERFORMANCE IS A CONCERN ....I want my car to perform as good as manufacturer desingn it to perform in stock form

 

Great......change them out to iridiums

 

ttt

 

I think the pucks were falling off the platinums

 

thanx for helping

 

leave them in, get couple tools, a chilton manual at library and LEARN to change yourself or go to autozone or friend to show/help you change unless you are just rolling in $$$$$$$
only rich or dumb people pay to have plugs changed on any car ever made in my opinion, sorry if I offend you...but the bottom line is it is up to you to do what makes you sleep at night. happy motoring after you make your choice.

 

ttt

 

Try finding the heat range for the different plugs then. If it's the same or within one range then you'll be OK. Don' t worry so much about them being the listed part or not.

Just to know, what vehicles use that plug?

Peter

 

That plug is used in a lot of Chevy`s engines but NOT the C5. AC Delco has that list on their website

 

The ACDelco Spark Plug Identification Table
Prefix and suffix letters are used to identify a specific type plus the numbers relate to thread size and heat range. For example, the R45TS spark plug shown is:

R = Resistor
4 = 14 mm Thread
5 = Heat Range
T = Taper Seat
S = Extended Tip
Plug Identification Table Prefix Identification Code Description
B Series Gap
C Commercial
CS Chain Saw
F Fine Line 14 mm 5/8" Hex
M Marine
LM Lawn Mower type
R Resistor
S Shielded (5/8-24 thread)
V Surface Gap
Prefixes are sometimes combined e.g., VB, CR

Numbering
1st number denotes THREAD SIZE
2nd number denotes HEAT RANGE
In the early 1990s, an all-numeric, identification code was developed to ensure that the proper spark plug would be selected for replacement in specific engine applications. The numeric code does not in any way correspond to the heat range of the spark plug. Therefore, selection of a spark plug with a different code number is not recommended. The heat ranges may be drastically different between two different plugs, and engine damage or poor performance may result. See your local installer or retailer for details.

The prefix “41” stands for the manufacturer’s product line (e.g., 41 = spark plug)
Numbers after the prefix indicate the type of spark plug and also the specific application:

100 – 199 = Iridium
600 – 699 = Resistor
800 – 999 = Double Platinum

from AC Delco web site....so if engine damage is something that could happen from an incorrect plug I`m taking them out tomorow morning and replace it with stock iridiums!

 

Ttt