Hi Everyone,
I did a little research on the
coils and I've found that most of the different brands of
coils for sale on
Amazon have one or two reviews that state that the
coils are slightly longer, but the cover is able to be put back on with a tighter fit. So, I may keep the
coils I bought, but will still call
Parts Galaxy when they open on Tuesday, I'll report back once I've spoken to them. I also found this really helpful review on
Amazon. Being a new Tbird owner, I feel the more I know about the
coil issue the better and the review below really sheds some light on why the
coils fail and what measures can be taken to prevent them from failing again. An ounce of prevention is always worth a pound of cure. When I take my Tbird to get the
coils installed, I plan on printing the below review and taking it with me to the mechanic so he can read the tips outlined below, so that I can maximize the time and mileage before I have to deal with this issue again.
Hope the below info is helpful!
3.0 out of 5 starsWork great, but caution, the connector sits higher than
OEM coils
By
Ibuyalothere on January 16, 2017
Verified Purchase
I bought these along with a set of Bosch Platinum +4
spark plugs to replace a different brand of replacement
coils that were starting to fail and causes misfires after a litle over three years and only about 10,000 miles on my 2003 Thunderbird. It currently has a little over 107,000 miles on it. The old
coils (bought on
Amazon) started to have misfires about a year ago. The Jaguar designed AJ-V8 engines used on the 2002-2005 Thunderbird and 2000-2006 Lincoln LS are notorius for misfire issues and rough running due to failing/failed
coils. The
coil misfires are often only a symptom of the problem. The root causes of the misfire issue are many, as are the solutions. I got about three years, although only about 10,000 miles, out of these
coils before they started to fail. Having said that, I have learned a lot about the causes of the
coil failures in these engines and how to keep them running as they should and I will share much of what I learned here.
First, before I get into solving misfire issues with these engines, let me talk about these
coils. Be advised, that the electrical connector on these
coils stand up a little above the top of the
coil. This causes some issues with putting the
coil covers back on as the connectors hit the top of the
coil cover. You can bolt the cover down over the top fo the
coils since it is plastic and will flex, but iIam not sure how water tight the coild covers will be after yo do that (see more about moisture below). I decided not to return the
coils and flexed the coild covers over them. One week later, the misfires are gone. Only time will tell how long these last. I bought them proimarily because they are supposed to have alifetie warranty. We'll see. Now on to what I hav learned about keeping engine issues at bay with the AJ-V8 engine...
If you start to have misfires/rough idling/rough running, it is "most likely" although not exclusively, the
coils (as long as you have kept up with other routine engine maintenance and repairs). Once one
coil starts to go bad, they will all start going so it is best to replace all eight at the same time. While you are at it, you should also replace the
spark plugs, since misfires can cause the
plugs to foul and new
coils will not fix that problem once the
plugs are fouled. I also recommend using Bosch Platinum +4
plugs (Bosch #4419) or equivalent as these
plugs resist fouling and misfires due to their design. They cost more than the
OEM plug, but it is is cheap insurance to help alleviate/minimize the misfire issue. These
plugs are a nice upgrade over the stock plug style. Do not overtighten the
plugs, you can strip out the threads as these engines are all aluminum. The torque spec on the
plugs is 18-20 foot-pounds of torque. Bosch also does not recommend the use of anti-seize compund as the plug threads have a special plating that resists the threads seizing in the bore over time.
When you change the
coils and
plugs, look carefully into the plug bores for evidence of oil and/or moisture. If you have oil in the bores, you need to replace the
valve cover gaskets. Leaking
valve cover gaskets are a known issue in these engines, especially the early years of these engines. Use the
Fel-Pro gasket set (available on
Amazon) as their design won't leak when properly installed. Follow the installation instructions exactly. Do not over tighten the valve covers when installing them. Use a torque wrench. I replaced my old gaskets with the
Fel-Pro gaskets and they have not leaked a drop of oil in over four years.
If you find moisture/water in the plug bores, you need to replace your
coil covers. Leaking
coil covers are also a know issue with these engines, especially in the early years (~2000-2003). The newer versions have an improved, thicker gasket and don't leak. These must be ordered from Ford. Do not over tighten the
coil covers! The torque spec is 44 inch-pounds.
The design of these
coils do not seem to lend themselves to long-term reliability, so sooner or later (usually sooner) they are going to start to fail. In general, these so-called "dry
coils" are less reliable than the good old oil filled
coils that were used before
electronic ignition systems. This
coil desing in particular seems to be very susceptible to failure due to moisture and the symptoms of them beginning to fail starts with misfiring from a "weak" spark. Moisture is the enemy in these engines, and the
coil covers seem to be a double-edged sword. The purpose of the covers is to keep moisture out, but they can also lock moisture in - which is a bad thing. These engines operate normally between 220-230 degrees Farenheit, above the boiling temperature of water. High moisture on metal combined with high heat causes corrosion/oxidation. Oxidation causes an increase in resistance in conductors. Increased resistance reduces the
coil voltage getting to the
plugs, and the reduced voltage causes weak spark or no spark, which in turn causes misfires. So, the solution is to keep moisture out of the plug bores in the first place, and second, to minimize the chances of corrosion/oxidation if mooisture gets under the
coil covers and into the plug bores.
When installing your new
plugs and
coils, first clean all electrical contacts with electrical contact cleaner, make sure they are completely dry, and then apply a thin coating of dielectric silicone tuneup grease to all electrical surfaces. Use a Q-tip to apply the grease, but make sure to not leave any cotton from the swab behind. Also apply
dielectric grease to the sealing area between the
coil and the rubber boot, and also on the
spark plug insulator where the rubber
coil boot goes over the plug.
Dielectric grease will not interfere with the transmission of electricity between the metal surfaces, but it will protect them from corrosion. This will increase the life of your
coils. Anectdotally, from reading many, many user stories over the past four years, and trying to solve all of my own issues with this engine, it seems as though the increased resistance from corrosion/oxidation in the mating surfaces between the
coil and the plug seems to cause premature failure of the
coils.