How hard is it to change out the plugs in A 07 Crown Victoria? There’s no wires. I’ve been told it takes all day. Is there anything I need to be careful of? Any advice would be gratefully appreciated. Thank you.
First, what car do you have, an 07 or 98?
Second, if you go on over to crownvic.net, they have plenty of tutorials and advice, along with a bunch of very knowledgeable members who know what they’re talking about… not that we don’t!
The most important thing, I guess, is to make sure the plugs are torqued to proper specs. Too little or too much can eventually result in the plugs blowing out of the cylinder head in the future.
I assume it is a 98, it doesn’t seem like it would be time to change the plugs in an 07 yet. Anyway, plugs on the 4.6L V8 in this car are very easy to get to and change. The car has COP (Coil On Plug). Just remove the bolt that holds each coil down and pull the coil and boot out. The plug is down in the well. The head is aluminum, so make sure the engine is completely cool and make sure to put something on the threads of the new plugs.
what they said, especially about going to www.crownvic.net. Please, please tell me that you have a torque wrench and you know how to use it!
I do not remember if this model uses a tapered seat spark plug or a gasketed plug. Many problems develop when spark plugs are overtightened in aluminum heads.
JMHO, but you should avoid the use of a torque wrench as many of those torque specs tend to be a little much. An example
could be a 14 Ft. Lb. spec on a tapered seat plug. That’s just begging for trouble on an aluminum head engine. You can get away with it on a cast iron head engine.
Many 1/2" drive torque wrenches are not very trustworthy at low torque numbers. A precision 1/4" drive torque wrench is accurate but often very pricy. I’ve got one and seldom even use it. Pricy and precision or not, some torque numbers are too high for the application.
To keep yourself out of trouble you should always reinstall new plugs NOT with a socket/extension but a short length of vacuum hose instead. Use a piece about a foot long that will fit snugly onto the end of spark plug.
Another option is to use a piece of tubing about 2" long on the end of a long shank Phillips screwdriver. Attach the plug and that will give a bit of rigidity for installing plugs inside deep plug wells.
With tapered seat plugs screw them in just until they touch and then turn about 1/16 of a turn more. NO more than that.
With gasketed plugs, run them down until they stop and then turn them about 1/4 of a turn more.
If you look up the proper NGK plug on the NGK website, you’ll be able to find the decoding secrets for the plug’s part number. That will tell you what type of plug it is, what seat, what thread size, and what the proper torque is if for steel or aluminum heads. Among other details.
Since the OP has disappeared, FYI, the plugs in this car, 98 or 07, are tapered not with gaskets.
There is no way in the world I would consider applying 10-15 ft. lbs of torque to a taper seat plug in an aluminum head.
That much torque will pull the threads at the very least and eventually, either through mileage or the next few times the plugs are removed, the threads will probably give up and then it’s Heli-Coil time.
Bump snug is about it IMHO.
I always look at the charts for decoding the part number. Relying on my memory would guarantee problems.