: Cannot remove spark plugs



bwgerho
03-05-11, 07:39 PM
2000 Cadillac Eldo, Northstar
I doubt the plugs have ever been changed - only 67,000 miles on the car. I read the shop manual (Helm Inc) about spark plug replacement - followed instructions. I remove the parts necessary to where I can get a socket over the spark plugs and should be able to remove them. I cannot get the plugs to loosen - the wrench seats on the plug, I attempt turning with a ratchet handle and I cannot budge them - no movement at all. I tried all 4 plugs on one side with the same results. I tried liquid wrench - did nothing. The shop manual shows plugs tighten to only 15 ft lb so they should not be tight at all.
Now, I know this is an aluminum engine, and I know aluminum expands twice as fast as steel. The ambient temperature was around 45 degrees F. How about if I have the engine at least warm such that the aluminum is expanded relative to the steel. This should help.
Anyone run into this problem and find a solution??

Ranger
03-05-11, 09:42 PM
Never heard of that before. Give them a short burst from an impact wrench if you have one. Trying it with the engine hot can't hurt either.

N*Caddy
03-06-11, 01:47 AM
Actually with the engine warm the spark plugs should be even more tight. think about the aluminum expands the same in all directions, including closing the hole around the spark plugs... But yeah they should not be that tight, maybe you need a longer ratchet. I would try that first before the impact gun. If you have a small pipe to slide it on the ratchet should help. Also at 67K the spark plugs are only about 2/3 of the way...you should be fine another 33K on the same plugs.

ternstes
03-06-11, 08:17 AM
I would do it with the engine cold. Six-point socket, long-handled ratchet and crack them loose. Even though they are only tightened to 15 ft-lb, it will take more force than that to loosen them.

Submariner409
03-06-11, 10:28 AM
:sneaky:............and you turn the wrench counterclockwise.

N*Caddy
03-06-11, 11:05 AM
............and you turn the wrench counterclockwise.


:histeric:

bwgerho
03-06-11, 01:05 PM
Yes, I have a 6 point spark plug socket with the rubber to protect the ceramic insulator.
Yes, Righty tighty, lefty loosey
Does anyone have experience using a "cheater" on aluminum heads. I know I have a handle long enough to remove something, but I fear removing the aluminum threads along with the plug. The steel plug will be fine, but the cast aluminum head is far weaker and I may twist the threads out of the casting.
As to expansion, if you heat a plate with a hole in it, the diameter grows.

Thanks in advance for experience/ideas

Regards bwgerho

ternstes
03-06-11, 01:57 PM
How long is your ratchet? Get some pb blaster or what not down the hole to loosen up any corrosion that may have formed. Let it sit for a bit and go at it. Sometimes slapping the end of the ratchet handle can apply a bit of extra force.

Ranger
03-06-11, 02:15 PM
Yes, I have a 6 point spark plug socket with the rubber to protect the ceramic insulator.
Yes, Righty tighty, lefty loosey
Does anyone have experience using a "cheater" on aluminum heads. I know I have a handle long enough to remove something, but I fear removing the aluminum threads along with the plug. The steel plug will be fine, but the cast aluminum head is far weaker and I may twist the threads out of the casting.
As to expansion, if you heat a plate with a hole in it, the diameter grows.

Thanks in advance for experience/ideas

Regards bwgerho

What is the difference? It's gonna take X amount of torque to break them loose. It matters not how you apply that force. A cheater bar only give you the ability to apply that force.

Submariner409
03-06-11, 02:28 PM
Some of the Ford 4.6's have a similar plug removal problem. Their solution is - cold - attempt to initially break the plug loose. Then apply a right fair amount of a penetrant such as PB Blaster and let it sit for an hour. (You're on their clock now). Now try to work the plug. Still stiff ???? More penetrant, go back to Square 1.

tateos
03-07-11, 01:06 PM
It's prudent to be concerned about threads in the aluminum cylinder block, but I don't think I remember ever reading here about anyone that had a problem with that with the N* engines. Use a breaker bar if necessary. I do also agree that it's a good idea to at least remove and inspect and perhaps re-install the same spark plugs before 100K miles have passed - before they get too locked in there.
It has been my practice to remove and either re-install or replace spark plugs after 50-60K miles.

I always apply a little anti-seize compound to the spark plug threads, then thread them by hand only (with the socket and extension) until fully seated. The anti-seize will usually catch anything it encounters in the threads. If I encounter any resistance or grittiness, due to debris in the threads, I stop, remove the plug, wipe the threads clean and start over. I only torque down and permanently install the plugs when I can fully seat them with only hand power.

N*Caddy
03-08-11, 07:44 AM
Be careful and applying force progressively until they brake loose. Although is not common as in Ford, I have seen 2 people here with thread issues on the spark plugs. Eventually they will brake loose with a small knock sound.

BTW, that rubber inside the spark plug socket is not as much for protection as for grabbing the plug.

ewill3rd
03-08-11, 07:49 AM
Once they break loose they will come right out, no amount of worrying is going to keep them from pulling the threads if they are going to.
I'd use a breaker bar or cheater on a ratchet and just bit the bullet and take them out.
They will come our or pull the threads but if you want to change them then you have to change them.
It's like ripping off a bandage, just do it.

Spraying something in the holes before you get them loose will do nothing, and anything you pour down there is going right in the cylinder as soon as they come loose, so be very careful. These have a pretty small combustion chamber and liquids don't compress.

stoveguyy
03-08-11, 11:11 AM
heating a cylindrical object will increase the bore size. use an impact and hope the threads don't shred. use your new plug to verify the socket size. for peace of mind.

bwgerho
03-30-11, 09:33 PM
Thanks to all: plugs are changed; below is what worked. Special thanks to Submariner409 - the tip of soaking really helped.
1. Warm the engine
2. While the engine is hot, spray BP blaster in each spark plug hole until you see liquid surrounding the plug.
3. Allow the system to set for several hours (4 or more)
4. Use a spark plug socked and a 3/8 breaker bar, apply torque until you feel the plug move 1/8 to 1/4 turn, tighten to re-seat the plug, loosen until you feel resistance (say 1/2 turn), tighten - this works the BP into the threads thereby saving the threads in the heads. DO NOT REMOVE PLUG WITH BP LIQUID STILL IN THE PLUG HOLE.
5. Use a long eyedropper - disposable plastic one used here - to remove BP liquid from hole. Finish removing liquid by stuffing a piece of paper towel down hole to soak any remaining liquid.
6. Remove plug, install new one with anti-sieze on plug threads and seat.
7 Do one bank at a time and park the car on a hill to minimize amount of BP Blaster in each hole. Park uphill for the front, and downhill for the rear.
End result was replaced plugs with no stripped threads.
Thanks again.

stoveguyy
03-31-11, 12:10 PM
park on a hill? its a 90deg vee motor so each bank is 45deg from vertical. to level the heads, you need to park on a 45deg hill? what, the side of mount everest?