Recommended spark plugs for 2006 Ford 4.0 V6

mercury
mountaineer

#1

I am going to be changing my spark plugs hopefully in the next month, as routine maintenance. I would like to hear any advice on the best plugs to use. Rock auto has Motorcraft SP412, Advance has that one and a special order F1000361106MTR, Autozone the SP412. And of course they all have other brands. Not looking to save money ($2 vs $6 each is not an issue). Any good/bad experience? Thanks!


#2

I would stick with the OEM plugs. I’ve never had problems with OEM plugs. But I had some issues with aftermarket plugs in the past, my 1992 T-Bird SC (back in high school) did not like Bosch Platinums, but did fine with OEM Motorcrafts. With that said, I’ve found that Autolite plugs tend to work well with Fords, and most Japanese cars tend to do well with Denso plugs, my Mom’s Benz does well with Bosch plugs (it uses 16 of them). But if you stick the OEM brand, it’s going to work.


#3

What @FoDaddy said - OEM, nothing to be gained with anything else.


#4

Denso and NGK are the OEM spark plug manufacturers for most/all Japanese manufacturers. In fact my 05 4Runner came from the factory with Denso on one bank and NGK on the other.

I’m pretty sure Motorcraft is the OEM manufacturer for Ford. Either buy them at Ford or any place that sells Motorcraft plugs. Usually the auto parts store will sell then at least 50% cheaper then the dealer.


#5

Definitely stick with the OEM Motorcraft plugs. I’ve done that with our Focus and haven’t had any problems with them at all.


#6

Make mine another vote to stick with OEM plugs and specs.
No other brand, no trifurcated magic electrodes, no laser-fire lightning-blast plugs, no trickery, no gimmickry. Just good old fashioned OEM replacement.


#7

To further clarify - OEM plugs does not mean ONLY plugs from the dealer. Some people actually believe that OEM is DEALER. Anywhere you can buy Motorcraft plugs is considered OEM.


#8

Thanks - I will go with the SP412. I do like using OEM when possible. As they say, dance with the one that brung ya.


#9

I’m not 100% certain, but I think Autolite is/was the OEM plug manufacturer for Ford

As far as other brands, I’ve noticed that those Bosch 4-electrode platinum plugs often don’t work so well for older cars that weren’t designed with such plugs in mind

Some cars came factory with those plugs, and for them I suppose it makes sense. But not necessarily for others

Personally, I always install exactly the plugs that are listed in the owner’s manual or factory service manual


#10

It looks like they used to be. From the wikipedia page:

“In 1961, seeking to enter the profitable aftermarket auto parts business, the Ford Motor Company acquired the Autolite tradename, an Ohio spark plug factory, a Michigan battery facility, limited distribution rights, and the services of several employees.[2] Autolite products became standard original factory equipment in Ford vehicles. A federal antitrust lawsuit was filed against Ford, which dragged on through the remainder of the 1960s, and Ford was forced to sell its Autolite-related assets to the Bendix Corporation by 1973.”


#11

Ironically, the Motorcraft are the least expensive-always good news. I did use Motorcraft oil and filter when I changed it a couple weeks ago.
I am hoping to have all the 100K maintenance items done by spring. I bought it at 140K, but it had no maintenance record, so I am going on the assumption that some items may have been overlooked.


#12

I love the saying!


#13

On my Ford truck I have always used MotorCraft plugs. On my Corolla I’ve always used NGK. Those are the same brand that were installed at the factory when the car was built, and never had any plug problems. As the car reaches a certain vintage sometimes the oem part number is no longer made, but they make another part number that is equivalent. The parts stores do the cross reference for you, as long as you request the correct oem brand.

Note that buying the oem brand at a general purpose parts store may not always yield the oem plug. Sometimes the manufacturers have different quality parts lines, and to get the actual oem part you have to ask for it, and it will cost a little more. Sometimes the only local source for the actual oem part is the dealership. This didn’t used to be the case, but the manufacturers are aware that diy parts buyers are very cost conscious, so to hold their market share they need to sell a less expensive line, which they try to make appear on the box to be the same as what the manufacturer of the car uses.

On my VW Rabbit, I switched around, using different brands as a sort of experiment to see if I could detect a difference. I seemed to get the best result using Champion for that car, and had some minor problems with Autolite and Bosch brands, but nothing serious. As I recall the problem w/the Bosch and Autolite is I had to replace them in fewer miles than the Champions, otherwise I’d start getting some pinging & misfires & hard starts.


#14

I learned years ago that the exact part number of the plugs installed at the factory on my Scion cannot be purchased. Toyota has assigned a very specific last number to “lock” the plug configuration in on the specification control number preventing any changes at the NGK factory. The exact number that the car came with can only be purchased by Toyota. The consumer can buy one exactly like the one Toyota installed, but the last alpha designator will be different. The one on the plugs the car came with are a “special”. It isn’t a problem as long as the customer realizes why the variation between the NGK recommended OEM replacement part number differs slightly from the one he pulls out of the engine.

In short, the NGK listing accessed by the parts store will tell the customer exactly what plug is required, but if the customer is changing the plugs for the first time a slight variation should not raise red flags, although it should always be double checked.


#15

Remove and install the plugs gently. You do not want to damage any threads and don’t get ham-fisted when tightening them up.

I always use a foot long piece of stiff vacuum hose to install them. The hose is fitted over the upper end of the plug and the plug is screwed in as far as possible with the hose before reverting to a socket. That will prevent cross-threading a plug.


#16

+1 on using OEM plugs. My former Honda got a set of really nice Bosch plugs. Kept trying to unscrew them! I had to re-tighten them periodically. Automotive transplant rejection! Switched back to NGK’s and that problem went away.


#17

All good advice - many thanks. George, I’ll be going to the next town over (Advance has them in stock; our local Autozone does not) this weekend and I’ll make sure they look authentic.


#18

As always, OK4450 has offered good advice. I personally recommend the use of a torque wrench for installing the plugs. Pros like OK4450 have installed thousands of plugs over the years and can pretty much tell when the torque is appropriate, but I don’t believe a newbie can do so. I believe a torque wrench is the way to go.


#19

I’ll borrow one for this. I did like @ok4450’s tip too.