Pulled a 7.3 Powerstroke glow plug and found the tip was a different length than I expected

I was doing a full glow plug change on a 2002 F-350 that came into the shop last Thursday. Grabbed a new set, part number ZD-11, and went to work. When I pulled the old ones, I measured one and the heated tip was a full 3mm shorter than the new plug. Checked the old box in the truck's glove box and they were the wrong spec, installed by the previous owner. Has anyone else run into a truck running on mismatched plugs for who knows how long?

3 comments

3 Comments

susan_brown801mo ago

Remember my buddy's truck with three different brands?

julia8111mo ago

Wow, that's a big difference... 3mm is no joke. Actually, @susan_brown80, that reminds me, your buddy's mix of brands is one thing, but running plugs that are physically shorter means they weren't even reaching the combustion chamber right. It's amazing it ran at all on cold starts.

the_brooke17d ago

Man, that's wild! I saw the same thing on a 6.0 last month, but it was only about 2mm off. The crazy part is the truck ran okay in the summer, but come winter it was a total no-start until we figured it out. How bad were the cold starts on that thing?