HOW TO: CHANGING SPARK PLUGS 99-04

code3GT · 04-19-2006, 12:22 AM

This write up was done by mself52...

If you guys are like me when you look at the engine when your about to change the spark plugs it looks very intimidating and looks hard... but in reality its very simple and takes bout an hour to 90 mins to change them with the right tools and a little direction... so i figured id do a write up for you guys....

to start with you DO NOT have to remove the fuel rail.... the only thing that you need to remove is the air intake from the throttle body...this is so you can get to the number 3 plug that is right under it...

tools needed include:
1) 5/8" spark plug socket
2) 6" extension
3) 9/32" socket
4) small tube of anti seize

now here is a picture with what you will actually be removing

you remove that small 9/32" bolt and that allows you to pull the coil from the plug hole it might be stuck good so just wiggle it around and pull but it will pop out...the only plug that you need to unhook the harness from the coil is on the number 4 plug which is on the passenger side at the back next to the firewall....its too much of an angle to bend the coil and get it back in without unhooking the harness...

after removing the coil this is what it looks like

and this is where the spark plug is

now before removing the spark plug if you look inside the hole there will be alot of debris that you should blow out with either canned air or a air compressor....

now that the plug is out take your new plug and put a few dabs of anti seize on the threads and smear it on all the threads... then wipe the excess off with a towel... now put the new plug in... hand tighten it and then snug it but DO NOT over tighten it because this is aluminum and will strip if you try and torque it too much... just snug it and then a slight bit tighter

now put the end of the coil back in the hole and wiggle it around while pressing down untill it is back in place and the bolt hole should line up and you put the bolt back in....

repeat on all plugs....

TIPS:
if you remove any of the fuel injector harness please becareful there is a little red gasket inside each plug so if it falls out make sure you put it back in before moving on.... and on the number 4 plug do yourself a favor and remove the coil plug and the fuel injector plug to give you room and so that when you goto put the coil back in over the plug you can manevuer it back in....

hope this helps and good luck

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mteberle · 10-26-2011, 12:37 PM

Do you have to remove the fuel rails to get to the other plugs?

cliffyk · 10-26-2011, 01:17 PM

Quote:

Originally Posted by mteberle

Do you have to remove the fuel rails to get to the other plugs?

Paragraph two from the above post:

Quote:

to start with you DO NOT have to remove the fuel rail.... the only thing that you need to remove is the air intake from the throttle body...this is so you can get to the number 3 plug that is right under it...

[emphasis added]

Also, as you may have noticed this is an 5-year old "how-to", "...just snug it and then a slight bit tighter." is about the worst advice one could give for an engine known to spit out improperly installed plugs resulting in $100 to $800 repairs.

Get a 1/4" drive torque wrench and torque the plugs to 11-13 lbft. If you absolutely have to make them hand tight plus another 1/16th of a turn...

mteberle · 10-27-2011, 12:50 AM

Sorry, I got to looking at the pictures and missed that line. I do have a torque wrench and will definitely use it.

I would like to be able to monitor my cylinder head temperature. I've seen thermocouples designed for this purpose that look like a ring lug which fits over the spark plug threads. Could such a device be used on this engine? My concern is that with the lead wires coming up out of the hole that the coil wouldn't fit. I don't really want to spend $40 on one and then it not work.

Thanks,

Mike

caaraa · 10-27-2011, 03:00 AM

Thanks guys,good site.

cliffyk · 10-27-2011, 10:08 AM

Quote:

Originally Posted by mteberle

Sorry, I got to looking at the pictures and missed that line. I do have a torque wrench and will definitely use it.

I would like to be able to monitor my cylinder head temperature. I've seen thermocouples designed for this purpose that look like a ring lug which fits over the spark plug threads. Could such a device be used on this engine? My concern is that with the lead wires coming up out of the hole that the coil wouldn't fit. I don't really want to spend $40 on one and then it not work.

Thanks,

Mike

That sort of thermocouple ring sensor should NEVER be used with tapered seat plugs, making the wiring issue moot...

kingrukus · 04-23-2012, 01:26 AM

is it advisable to use anti-sieze? the reason I ask is because it will probably mess-up the torque readings on my torque wrench when tightening, ultimately allowing me to over-torque.

JC316 · 04-23-2012, 02:12 AM

Quote:

Originally Posted by kingrukus

is it advisable to use anti-sieze? the reason I ask is because it will probably mess-up the torque readings on my torque wrench when tightening, ultimately allowing me to over-torque.

Oh yeah, anti sieze is a must on any spark plug. And LOL at torque wrench. I know a lot of people use them, but on spark plugs, I just crank em down till they are tight.

trailor · 04-23-2012, 01:42 PM

anti-seize, while not discouraged, is not recommended by Ford. there is no need for it if you torque them down to spec....

cliffyk · 04-23-2012, 06:41 PM

If I did not have a proper torque wrench (a situation I cannot envision), and given the many years I have been doing this sort of work, like JC316 I too would likely torque them based upon "feel". However I would not recommend, or support such a recommendation, being made to anyone else.

It would be quite unwise to not torque the plugs on these engines for at least a couple of reasons; the use of tapered seat plugs in plug bores with minimal threading, and that it is almost commonplace for our engines to spit out plugs that were like not torqued properly or installed in bores damaged by over-torquing in the past.

Ford's engineers decided to recess the plug bores and leave only 5-6 threads remaining at the bottom of the bore. I am certain this was done because of the extended service life of the platinum plugs chosen for OEM fitting--100k miles. Anti-seize would not survive that long, and a 3/4" reach plug in a fully threaded bore would certainly seize up over that period, 6 to 8 years or more of "normal" driving in the US.

Under normal service intervals the plugs in our cars would only be changed once (at 100k), maybe twice (at 200k) over the entire life of the vehicle. It's only we "enthusiasts" that change them about as often as our underwear--I changed mine 3 to 4 times a day, over a period of a week and a half, last summer when doing field tests for a COP and plug vendor.

Get a 1/4" drive torque wrench, an 8" extension, a 1/4" to 3/8" adapter, and a decent plug socket (Google "extended spark plug socket").

Since last fall I have been using a torque limiting plug socket: