Changing Spark Plugs on Northstar?
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 22
Northstar Engines and System Technical Discussion Discussion, Changing Spark Plugs on Northstar? in Cadillac Engine Technical Discussion; hi all this is my 1st post on these forums. well anyway, my father has an 1994 cadillac deville concours, ...
  1. #1
    caddybrougham87 is offline Cadillac Owners Member
    Join Date
    Sep 2004
    Posts
    18

    Question Changing Spark Plugs on Northstar?

    hi all this is my 1st post on these forums. well anyway, my father has an 1994 cadillac deville concours, and the spark plugs need to be replaced. he tried doing the job, but couldnt and broke a wrench in the process. i was wondering if someone could give directions or a step by step process on how to change the spark plugs for this northstar engine. also we are going to change the wires if anyone knows how to go about that, that would also be great. thanks

    Paul

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    foo
    foo is offline Cadillac Owners Fanatic
    Join Date
    Oct 2003
    Posts
    102

    Re: Changing Spark Plugs on Northstar?

    It's real easy with a socket extension and a socket wrench with flexible head. The plugs are really in there tight though, if you can get an air impact to get them out it would be better but I got mine out ok without it

  4. #3
    Roswell256's Avatar
    Roswell256 is offline Cadillac Owners Fanatic
    Join Date
    Feb 2004
    Location
    Quantico, VA
    Age
    32
    Posts
    285

    Re: Changing Spark Plugs on Northstar?

    I have a 94 Concours and have replaced my wires and taken out my plugs

    The easiest way that I've found to do this is to take the coil pack off the top of the engine.

    When you look at the engine standing in front of it. The coil packs are to the back left. you can't miss them as its where all the plug wires terminate. There should be 3 screws if I'm correct. One on each side and one on the back. After unpluggin the two wires on the left and the two wires on the right, unscrew it and set it up on top of your enfine. Now pull the plugs in the back. Replace the plugs and then one by one. Pull the wire off of it. Match it to the same length one on the new set and replace the wire. Once you have the back done you can go ahead and put the coil pack back on if you'd like. Just put it on in the reverse order that you took it off.

    Now do the fron. one by one take the wire off, match length, then replace. Its that simple. If you have any problems let us know. We will be glad to help.

  5. #4
    eldorado1 is offline Cadillac Owners Connoisseur
    Join Date
    Feb 2004
    Location
    FL
    Posts
    2,250

    Re: Changing Spark Plugs on Northstar?

    I would highly recommend you NOT using an impact wrench on the spark plugs, unless you like removing the heads, and retapping the plug holes for larger plugs. If you broke a wrench, you must've been using one of them chinese wrenches... they're not in there all that tight, as long as the last person put antiseize on the threads (assuming it was changed after the factory ones)

  6. #5
    ShadowLvr400's Avatar
    ShadowLvr400 is offline Cadillac Owners Connoisseur
    Automobile(s): 1996 Fleetwood
    Join Date
    Oct 2003
    Location
    Central Florida
    Age
    31
    Posts
    2,530

    Re: Changing Spark Plugs on Northstar?

    Removing the coil packs does make getting the rears out a lot easier. If he broke a wrench, the previous person over tightened or didnt anti-seize the plugs when installed. You'll have to figure out a way to get the leverage to break them loose. Additionally, you can spray some WD-40 or other greaser/deruster in there. Next time you start the car, it'll burn the stuff out with a bit of an odd smell, but not overly dangerous. (Just dont pour gallons in.)

  7. #6
    BeelzeBob's Avatar
    BeelzeBob is offline I'm a Cadillac Fanatic!
    Join Date
    Dec 2002
    Location
    Fort Lauderdale, Florida
    Age
    49
    Posts
    9,577

    Re: Changing Spark Plugs on Northstar?

    Use an air impact to knock them out. The shock of the impact is a very effective way of removing the spark plugs in an aluminum head. It will not hurt the threads. You obviously do not want to install the new ones with an impact but taking the old ones out is commonly done with an impact with great success in my part of the woods..... If the threads are damaged with an impact then you would have surely damaged them with a normal socket and rachet....if you get them out at all.

    Never use antiseize on spark plugs. The OEM plugs that GM provides are nickel plated on the shell to prevent seizure and corrosion but they will stick in the head pretty hard. Anti seize can cause severe overtorqueing of the plugs due to the slippery nature of it and it can easily foul the spark plug electrode and porcelean..especially if you every try to start another plug into the hole with antiseize on the female threads in the head.

  8. #7
    eldorado1 is offline Cadillac Owners Connoisseur
    Join Date
    Feb 2004
    Location
    FL
    Posts
    2,250

    Re: Changing Spark Plugs on Northstar?

    Quote Originally Posted by bbob
    Never use antiseize on spark plugs. The OEM plugs that GM provides are nickel plated on the shell to prevent seizure and corrosion but they will stick in the head pretty hard. Anti seize can cause severe overtorqueing of the plugs due to the slippery nature of it and it can easily foul the spark plug electrode and porcelean..especially if you every try to start another plug into the hole with antiseize on the female threads in the head.
    I'm still going to use antiseize on my plugs... Granted, more than likely I'll never replace them again (assuming they last 100k), but I'll make it easy on the next guy

    "Most threads on spark plugs designed for aluminum head applications are precoated to reduce the risk of thread damage. If you’re in the habit of applying a drop of antiseize compound to the plug threads before they go in for added insurance, you might want to reconsider this practice. One vehicle manufacturer warns against this practice because antiseize acts like a lubricant and may allow the plugs to be overtightened—which can damage the threads. Their advice is to reduce the tightening torque on the plugs 40% if you decide to use antiseize on the threads."

  9. #8
    growe3's Avatar
    growe3 is offline Cadillac Owners Enthusiast
    Automobile(s): 1993 STS and 2004 DTS
    Join Date
    Oct 2003
    Location
    Cameron Park, CA
    Posts
    564

    Re: Changing Spark Plugs on Northstar?

    I have not had any trouble removing the spark plugs. They can be tight, but it is not that big a deal.

    I would never use an impact tool on a spark plug. There is no need to do so.
    If the plug is that seized, I would rather rock it loose with a 1/2" drive ratchet, with a little penetrating oil and work it out; rather then "rip" it out with an impact ratchet.

    To make it easy, I just use a 1/2" drive ratchet to crack them loose, then spin them out with my 3/8" drive ratchet.

    To install them just us the 3/8" ratchet.

    If you use a flex joint or better yet a flexible spark plug socket, there is also no need to remove the coil pack.

    -George

  10. #9
    caddybrougham87 is offline Cadillac Owners Member
    Join Date
    Sep 2004
    Posts
    18

    Re: Changing Spark Plugs on Northstar?

    thanks guys, keep the info coming if you got some. so far its been a big help. i will probably attempt to change the plugs and wires this weekend with my father.

  11. #10
    CadiJeff's Avatar
    CadiJeff is offline Cadillac Owners Connoisseur
    Automobile(s): 1981 CoupeDeville, 2 1990 Eldorados, 1994ETC ,1992STS
    Join Date
    Feb 2004
    Location
    Nerk,Ohio
    Age
    34
    Posts
    1,072

    Re: Changing Spark Plugs on Northstar?

    First of all, WELCOME!

    hmmm broken wrench?................your sure this is a northstar and not a 4.9?(they still made those in 94 right?) The n* plugs are easy to change. Just get a plug socket,and an extender, the plugs are right there on top of the heads in the valve covers. It shouldn't take more than 20 min to do. if you are having problems geting to the rear ones try removing the strut tower brace. The wires are even easier just remove the protective plastic wire cover on the drivers side and replace them one at a time. While your at it you might consider replacing the coil packs being a 94 (asuming they are the origional) they are probably starting to wear out.
    good luck

  12. #11
    94CaddyConcours's Avatar
    94CaddyConcours is offline Cadillac Owners Fanatic
    Automobile(s): 1994 CADILLAC DEVILLE CONCOURS, 350ZR
    Join Date
    Jul 2004
    Location
    LONG BEACH KALIFORNIA, HOUSTON
    Posts
    444

    Re: Changing Spark Plugs on Northstar?

    I just changed my spark plug couple month ago. What kind of brand do the majority of Cadillac owner use OEM or Aftermarket.
    -Bill

  13. #12
    eldorado1 is offline Cadillac Owners Connoisseur
    Join Date
    Feb 2004
    Location
    FL
    Posts
    2,250

    Re: Changing Spark Plugs on Northstar?

    Quote Originally Posted by 94CaddyConcours
    I just changed my spark plug couple month ago. What kind of brand do the majority of Cadillac owner use OEM or Aftermarket.
    -Bill
    <shrug> I think I put in autolite double platinums. I don't like Bosch's stupid 4/3/2 prong designs, so I had to have the shop order them :rolleyes2

  14. #13
    caddybrougham87 is offline Cadillac Owners Member
    Join Date
    Sep 2004
    Posts
    18

    Re: Changing Spark Plugs on Northstar?

    great news all, my dad changed the spark plugs and wires today, and he said the car is really purring now. thanks for all your help.

  15. #14
    peteski is offline Cadillac Owners Enthusiast
    Automobile(s): 85 Eldo Biarritz
    Join Date
    Dec 2003
    Location
    Northeast USA
    Posts
    808

    Re: Changing Spark Plugs on Northstar?

    Quote Originally Posted by eldorado1
    <shrug> I think I put in autolite double platinums. :rolleyes2
    I seem to recall recent spark plug thread where Bbob specifically recommended against using Autolite plugsin N* . Search the archive if you are interested.

    But judging from your posts on this thread, you seem to disagree with Bbob in general...

    Do what you like...

    Peteski

  16. #15
    94CaddyConcours's Avatar
    94CaddyConcours is offline Cadillac Owners Fanatic
    Automobile(s): 1994 CADILLAC DEVILLE CONCOURS, 350ZR
    Join Date
    Jul 2004
    Location
    LONG BEACH KALIFORNIA, HOUSTON
    Posts
    444

    Smile Re: Changing Spark Plugs on Northstar?

    What wrong with using autolite?

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting