OlGeezer

I've got a 1999 GT 4.6L 5 Speed.

I'm about to undertake changing the spark plugs for the first time. I am NOT a mechanic, but I follow instructions. Unfortunately, the picture in my Chilton manual is of a dual overhead cam engine and looks nothing like mine.

Is there a procedure available (hopefully with pictures) that will help me do this right and not remove the fuel injectors by mistake?

Thank you,

FlamingoGT

https://mustangforums.com/forum/4-6l...s-99-04-a.html

MustangMan00

it may be a daunting task, but its very simple, just remove the intake at the throttle body and that's all you need to take off other than the coil packs

1998Slow 'Stang

I know how people feel about posting hear-say, but, I've HEARD that changing plugs with the engine hot, or even warm, just about multiplies the chance of the plug taking the threads in the head with it. I believe I heard that here in fact, I just choose the safe route and do it first thing in the morning after the car has sat all night.

Just my .02, and, if I'm wrong on this someone please do correct me.

cliffyk

There is no such caution in the shop manual, and there would be if Ford's engineers felt it needed--however it is good practice to not change them on either an extremely hot or extremely cold engine. There is a TSB for the '05+ 4.6L that says to change them with the engine at "room temperature, however I could not find any such bulletin for the earlier engines.

I have swapped plugs (and COPs) literally 2 and 3 times a day while doing field trials for an aftermarket manufacturer with no ill effect, in each instance I let the engine cool to "warm" (140°F or so) before swapping the plugs.

I DO use a torque wrench to tighten them each and every time, and would not recommend that anyone not do so; especially a "newbie". HF has a nice 1/4" drive clicker that is often on sale.

While you are there pick up this extra deep spark plug socket, it greatly minimizes the possibility of the socket getting cocked on the plug--which can also create problems--and lines things up very well when installing the new plugs...

1998Slow 'Stang

Thanks for settin' me straight on that one Cliff. I've been wondering about that myself for a while now.

craigjschr

could i use a 3/8 drive torque wrench or is it to big and also what is the recommended amount of torque. also should i stick with ford plugs

medsav

as you can get, but i just changed mine out last week.. with a 10 inch extention and a swivel spark plug socket.... didnt have to take anything off but the cold air intake filter.....

cliffyk

A 3/8" drive wrench is OK, but I really recommend using a 1/4" drive wrench as it will be more accurate. 11-13 lbft is in the lower 25% of a typical 3/8" drive wrench's range, it's in the upper 30% of a typical 1/4" unit's range.

As to plugs I can only offer my position--I run Champion plugs in most every vehicle we own or have owned, stk# 3401 single platinums¹ in my '03 GT.

Champion has been making spark plugs for over 100 years, if there were some better way to make them they would have figured it out a long time ago...


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¹ - Actually I have the same plug in a double platinum flavour (stk# 7963) in there right now as I was testing some aftermarket COPs that fired with a reverse polarity.

brownlinemetalworks.com

I agree with Cliff. For that amount of torque, I think you would be better off with a 1/4" drive wrench.