650NutKase

I believe the actual ignition coils are the same. The difference is in the boots. The black boot is longer than the brown.

Not all 08 MODEL years have brown boots. If the engine build date is before 10/07, then they use the old style, black boots.

Mulestang

I believe the revised cylinder heads have different COPs. According to RockAuto:
Motorcraft DG511 w/Black Boots {#3L3Z12029BA}
Motorcraft DG521 w/Brown Boots {#8L3Z12029A}


My boots were dirty, and it was hard to tell the color. Someone on here told me to go by the coil, and they were spot on.

techrep

iTrader: (1)

^^^this^^^

650NutKase

what exactly is different between the two coils? Is it just form factor?

tuflehundon

I know one is longer than the other. I'm not 100% sure which is longer though. Haven't seen the 2 side by side to know. They redesigned the heads mid 08 model year.

techrep

iTrader: (1)

The new heads started showing up in the first part of Sept.07 with the first engine build date of 10/09/07... so any 08 5.4 sold prior to that date will defiantly not have the new heads.

Mulestang

One boot may be longer than the other, but I don't see a physical difference between the two coils. By the look of things on eBay and RockAuto, the brown boot looks longer.

Martian

Isn't the bolt hole in the coil itself in a different place on the new design?

Mulestang

Another question: Since I'm re-using the COPs, is there any trick to removing the old spring and installing the new ones (at the COP end)? Does it pull off with the old boot? Probably self-explanatory, just wondering if there are any tips/tricks.

Martian

Not really, it just sort of pops into the coil. Treat it like a screw and screw it out / in to take advantage of its shape and get it in the coil tightly when you put the new one in there.