Changing spark plugs on a Northstar

[fixitagain1]

Hey I also have a 99 seville with the same problem....gonna start swapping plugs tomorrow fingers crossed thats whats wrong ...quick question for you about resetting / getting engine error codes off the car....how????

[Ranger]

See the "sticky" in the Tech Tips section.

[nigelb]

the FSM says that the motor can go for 100k miles before the plugs need changing, thats by using the recommended OE plugs.
the fact that GM would say their plugs can last 100k miles is good enough reason for using them.
would bosch stand behind such a claim?

[jimfulco]

My AC platinums died with only 70K or so (they came in a used engine). I put some basic everyday Champions in and they work fine.

Using a magnetic spark plug socket makes the whole job a whole lot easier. I paid excess bucks for one off a famous-brand tool truck, but you can get one for <$10 from one of the mail-order joints if you don't mind the wait.

[Dadillac]

I paid $5 for my spark plug socket, and it works great for the N*. I got it from www.harborfreight.com. It is an extended socket that is about 5 or 6 inches long. To retrieve it from the spark plug hole, just use a pair of needle nose pliers. The socket and the holes are the same depth.

Don

[jh225]

Originally Posted by Dadillac

I paid $5 for my spark plug socket, and it works great for the N*. I got it from www.harborfreight.com. It is an extended socket that is about 5 or 6 inches long. To retrieve it from the spark plug hole, just use a pair of needle nose pliers. The socket and the holes are the same depth.

Don

Don't use a needle nose pliers or any other pliers, why risk cracking the plug or scuffing the head?

Changing plugs on a N* is simple.

Just loosen all the plugs with a plug socket, and leave the plugs in the holes. Then take a 12" piece of 3/8 fuel line, stick it into the plug hole, over the plug, push it on a little bit and pull the plug out.

Installation is reverse of above.

This is actually the way I change all plugs in any car. No chance to screw anything up, and you can easily get the threads started without crossthreading.

[Dadillac]

Originally Posted by jh225

Don't use a needle nose pliers or any other pliers, why risk cracking the plug or scuffing the head?

Changing plugs on a N* is simple.

Just loosen all the plugs with a plug socket, and leave the plugs in the holes. Then take a 12" piece of 3/8 fuel line, stick it into the plug hole, over the plug, push it on a little bit and pull the plug out.

Installation is reverse of above.

This is actually the way I change all plugs in any car. No chance to screw anything up, and you can easily get the threads started without crossthreading.

No chance of breaking the plug or scuffing the head. The socket is even with the top of the head, and you only need a little pull to get the spark plug out of the rubber insert in the socket. It is faster than using a rubber hose. But thanks for the input.

Don

[Rafterd]

Well I have always been the guy that dances with the girl who brought me.
While working on the STS I will use AC Delco. If working on my Ford Diesel Piuck up, I use Motocraft. My wifes Dodge Diesel Pick up gets Mopar. That is the parts they come with and seem to last the longest.
My 2 cents
Bill

[willseville]

I read some posts here, and I agree completely about original parts for replacements.

So I just bought original plugs AC 41-902 here in France for my 1992 Seville 4.9L, And I don't know what is the gap...

Is it possible for somebody to give it me ? I searched in the books , and I have no shop manual, I will order one !

Thank you !

[muzizman02]

ya don't use bosch the ac or champs plugs cost too for this car and work very well.leave the bosch plugs for the bmw's and such

[willseville]

Muzizman02,

I agree, my Cadillac I purchased last 16th october, is going to run only with original parts !

Is somebody here able to give me the gap for my new plugs I have to change tomorrow.
It is written on the box, like you know " set the gap with vehicle specification"

It is the first time for me, and I don't want to brake something...

Thanks !

[submariner409]

willseville,............the spark plug gap is .050".

Perhaps someone with a 4.9 can give you more details........look in the other engine forums, as 4.9 is next one down from N*.

[Ranger]

Originally Posted by willseville

I read some posts here, and I agree completely about original parts for replacements.

So I just bought original plugs AC 41-902 here in France for my 1992 Seville 4.9L, And I don't know what is the gap...

Is it possible for somebody to give it me ? I searched in the books , and I have no shop manual, I will order one !

Thank you !

Plug gap is .060
Northstar is .050

[willseville]

You are great !

Thank you so much to you, Submariner409, and Ranger !
Tomorrow afternoon I am going to change it, and just after, when hot, oil and oil filter, I bought a "PF 58 " AC oil filter.

A bientôt !
Will.

PS : sorry for my mistake : "I don't want to "break" something", sometimes I write like I hear.

[willseville]

One more time great thanks to you !

I have changed my plugs this afternoon, my Cadillac runs very well, idle is very good now, there was waves before, even on the road, at 80 km/h for example.

You are going to understand because the car did not run well before, I never have seen that in my life :
The last plugs AC had ... 1.55 instead of 0.60 !!! mounted from the box to the engine.

I wait for my air filter, and gas filter, and I will look the ignition cap, wires are good.
And the evening, it is 6.20 PM here, my car gives its power, with a very nice V8 "music", smooth and very comfortable to drive.
I am very glad.

It was very funny to place the plugs under the windscreen engine side, I was on a carpet, on my engine

It is easy to do, with good tools, I am a quiet guy, one hour to do that job.