Time to replace the glow plugs
 

I have a 99 f250 psd 4x4 and it has over 244000 miles on it with the original glow plugs in it. After spending a year in chicago I realize that they are not working as good as they use to so I would like to replace them. I am just curious if anyone has any tips or recommendations on this process?

PaysonPSD has a good little write up on it I believe. Biggest thing IMO is use Motorcraft only, made in Beru, Ireland. Alot of us has seen issues with others like Autolites.

Do you possibly have a link for the write up?

HEY! Check your Glow Plug Relay first and make sure its working!

Welcome to guzzle's Stancor GPR replacement Mod Web Page

I just recently replaced the glow plug relay because it completely stopped working.

i dont know much about glow plugs other than they are a externally solid metal object that is heated by electrical resistance, so i am wondering if they go bad due to the internal resistance dropping off, or do they stop transmitting there heat from "gunk" build up on them? i guess in short term can the glow plugs be scotch brited off, because my glow plugs work for sure most of the, i just have to let it sit longer than if they were brand new and they seem simple enough to clean off, has this been done?

sorry if thread jack but thought it was a pertenant question to be asked before one spent $8+ on them

i mean after all if i can remove them clean them off so they transmit there heat better and get another 25k+ out of them i think it would be time well spent

Here's a GP write-up from tdpower (2nd post). Have not done my GP's yet but looks pretty simple?

Hope my linking skills still work.

https://www.ford-trucks.com/forums/8...que-specs.html

Still looking for PaysonPsd write-up.


....Tom

They are basically a very small oven element.
They get hot enough to glow red hot and burn any deposits right off of them when they are working properly.
If they are not heating up, the only recourse is to replace them.

Here is another post with pics:

https://www.ford-trucks.com/forums/9...-pictures.html

I'm not trying to be a smarty pants but how I see it, once you spend the 3 plus hours in labor pulling and replacing the valve covers and all the stuff in the way of the glow plugs, you might as well spend the $8 and replace them. A new set can last you a good 100k - 200k miles. But stick with the Motorcraft ZD-11's.

Glow plugs go bad one of two ways that I know of. They heat cycle and after a certain number of cycles, the coil inside parts making the resistance go to infinity which means, no current will flow. That is why you can 'ohm' them out to find bad ones. The coil has a minute amount of resistance when it is a complete circuit, but a broken circuit won't transmit current. The second way a glow plug can go bad is that it was made with inferior parts, and when the coil heats, there is a certain amount of elongation/distortion of the coil. If it is made with a low grade metal, the coil will touch the main body and short out. Then you have no glow plugs. I guess I kind of think of it as a filament light bulb. The coil is similar to the filament sort of.

Make sure to get motorcraft ones. Non motorcraft ones fail due the coil being subpar, or they can swell and have the tip break off in cylinder.