Hi I just received Motorcraft spark plugs for my car and I am considering doing them myself to save money. However, I have never changed spark plugs myself and I know from the forums that removing and installing spark plugs on these cars can easily cross the threads, have spark plugs blow out later, etc. I do have the correct Haynes repair manual and I am trying to get the confidence to do them on my own. But am worried that I will mess something up or have them blow out. How finicky are the spark plugs to remove & install? Does anyone have any tips or tricks for this procedure?
spark plug question
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bbf2530
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Hi 04TC. According to the vehicle and how accessible the plugs are, it is a simple job, if you take your time.
They will not "blow out" if they are tightened down correctly. And it is very difficult to cross-thread them if you start them by hand, take your time and use a minimum of care.
Here are a few hints from my shade-tree mechanic days:
-Make sure you have the correct plugs and the plugs are properly gapped for your vehicle. Do not assume they are gapped properly. The specs are usually listed in the maintenance section of the Owners Manual.
-Make sure you have all the correct tools before beginning. Ratchet, extension/extensions, correct size spark plug socket, anti-sieze (if called for) etc.
-After moving/removing any components necessary to gain access to all the plugs, carefully blow out/clean the spark plug wells before beginning to remove any plugs.
-Fully seat the socket on the plug. Keep the socket straight, so as to avoid breaking off the insulator.
-Remove and replace one plug at a time, replacing the spark plug wire before going on to the next plug (don't want to mix up wires).
-Start threading in the new plug by hand. Use the socket and an extension only if necessary for access, but use your hand (not the ratchet/socket wrench) to turn it in. Install it by hand until the plug is threaded down hand snug. This will avoid cross-threading.
-Tighten down to the recommend torque specification. When I was younger, I simply tightened it down tight, but not Magilla Gorilla tight. However, with aluminum blocks and other modern engine factors, purchasing a torque wrench is always a good investment.
-Again, remove one plug at a time, replace the wire, then move on to the next plug and repeat.
Those are just few tips off the top of my head. I am sure I missed something and others will jump in with their own advice and recommendations. Also, you can also probably find some good How-to videos by Googling, "How to change 2004 Lincoln Town Car spark plugs". If there is nothing, just make the Google search phrase a little less specific.
Let us know how you make out and good luck.
dave42
Senior Member
Those are all great tips for any car. Since '04 is I think one of the years with a few holes having only a few threads, I would really stress the torque wrench part. On our TC's I think some of the plugs are a little hard to get to, and various extensions, wobble sockets and/or U-joint might be needed. Might need more than one type of 7mm wrench or driver to reach all the coil screws, too. New boots are inexpensive and a good idea to replace those as well. Some folks like to use certain kinds of grease on the springs as well.
Something I'm wondering about, partially because of the minimal threads issue (mine is '03), if plugs have been in a really long time, would adding some Kroil or other penetrating oil into the well a day earlier help them to break loose?
Something I'm wondering about, partially because of the minimal threads issue (mine is '03), if plugs have been in a really long time, would adding some Kroil or other penetrating oil into the well a day earlier help them to break loose?
wolf_walker
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Assuming nobody has left you a nasty surprise in there, it's pretty easy all in all. You do need the right tools, and a spark plug socket that will hold the plug in (or one of the other ways to do that) and an air compressor to blow crap out of the plug well is a good idea. Absolutely torque wrench them.
My 04 had one failed and ill repaired I discovered on a sunday evening right after I bought it, I re-ill repaired it and next time the head will have to come off I imagine. They are a trouble spot on these things, but not the worst offenders.
My 04 had one failed and ill repaired I discovered on a sunday evening right after I bought it, I re-ill repaired it and next time the head will have to come off I imagine. They are a trouble spot on these things, but not the worst offenders.
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Thanks for all the suggestions guys.
@wolf_walker does that mean if I mess up the spark plug removal/install the heads will have to come off when I next have to replace the plugs?
@dave42 Yes, penetrating oil especially if whoever did them last didn't put grease/anti seize on the plugs
@wolf_walker does that mean if I mess up the spark plug removal/install the heads will have to come off when I next have to replace the plugs?
@dave42 Yes, penetrating oil especially if whoever did them last didn't put grease/anti seize on the plugs
Corsart
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I'll be contarian here, and state the obvious: if you have to ask, you probably shouldn't try it. There's a lot that can go wrong if you lack the experience. My suggestion is to have a friend with that experience join you and watch him do it, so next time, you will confident in your own abilities. I'm not one who thinks car mechanics is intuitive.
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Ok thanks for the viewpoint.
dave42
Senior Member
Well, I wonder if they put anti-seize on at the factory? Yes, I must confess, my car has the original plugs at 196K miles. I have had a new set of Motorcrafts in the trunk for the last 50K miles. Life and a bad back got in the way. A friend was going to help me over a year ago, then Covid hit. Anyways, I'll get to it eventually!
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Corsart
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196K on a set of plugs? do us a favor, when you take them out, measure the gap, and let us know along with a pic.Well, I wonder if they put anti-seize on at the factory? Yes, I must confess, my car has the original plugs at 196K miles. I have had a new set of Motorcrafts in the trunk for the last 50K miles. Life and a bad back got in the way. A friend was going to help me over a year ago, then Covid hit. Anyways, I'll get to it eventually!
The plugs typically have a thin coat of anti seize on the threads applied when the plugs themselves are made. After 200k miles it's anyone's guess. There's no harm in a squirt of anti seize and an overnight for sure.
Vladimir2112
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Take your time! Don't use the flexible extensions! Those you have to put pressure on to make them flex making it very easy to cross thread. Use standard universal joints to get your socket and your extension straight down in the hole. You don't have to keep that kind of tension on them so you get the feel when the plug is threading in. Gives you that feel in your hands. I use the trick with courser threads. Once your sockets in place to tighten. Back the plug up a bit with a little pressure and you'll feel the plug drop back down as it hits the correct spot. It lets you feel in your hands that it's all going good. Make sure you have a vacuum to clear out the holes you don't want any debris in your cylinders. It's really not that hard. But you have to go in confident. Watch some YouTube videos. A-1 Auto has the best I think. They often do Grand Marquis and Crown vics. And the Ford trucks that use the same motor. It would be the exact same process
wolf_walker
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There are several ways to repair a bad thread in-place, some better than others. Ford has an approved procedure it was common enough to happen on some of these motors. It's a moron design, even the "better" ones like ours. I say that about mine since it's already been improperly repaired once, isn't likely the correct repair will be viable. But I expect the new set in there to last as long as I want to drive the car, so it's probably fine.
I recently replaced the plugs on my '04. Plug socket, elbow, extension and go slow. Dialectric grease just a dab on the boot opening. Do one at a time. The two closest to the firewall are the most difficult but not too bad. I used motorcraft plugs and they were properly gapped but verify as someone has said.
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Ballyhoo
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Changing them is extremely easy. Make sure to use a spark plug socket (rubber insert to grip the plug) and not the standard type since the plugs are down in a hole. Once out, simply drop a new one in. They will center with no problem. I changed them, and the coils, in mine at 107,000. The hardest one to do is the back driver's side where you'll need a 7mm wrench with the injector close and fuel rail not quite allowing an extension to clear squarely on the bolt. But I did all eight in under an hour. On a side note, install them with a standard socket so the spark plug type won't separate from the extension and remain in the hole. Yeah it happened, had to take it back out and reinstall again.
2003_TC_Executive
Junior Member
Guilty, my 03 has 193k and I can find nothing in the carfax report or folder of receipts from the previous owner that shows they have been replaced. Thankfully the did replace the intake around 110k.Well, I wonder if they put anti-seize on at the factory? Yes, I must confess, my car has the original plugs at 196K miles. I have had a new set of Motorcrafts in the trunk for the last 50K miles. Life and a bad back got in the way. A friend was going to help me over a year ago, then Covid hit. Anyways, I'll get to it eventually!
Vladimir2112
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Mine were changed at 67 K . On a 1998 That was shown to have sat for 6 years . I drove it a bit then changed them.Its a great way to check on your engines health. Even if pulling and checking your plugs and reinstalling because you find them to be good still. You could tell a lot from a plug. Changing my plugs I found the spark plug boot had dry oil and debris. I'm driving it and I'll check back on it to see if I need to actually change the valve cover or not. I didn't see a trail of oil coming from that cover.
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