when is it time to replace glow plugs

[shoctor]

This may seem like a dumb question but how would you know when to replace your glow plugs is it by mileage, time, time to start? Also how bad is the replacement and how does the end of the glow plug break off? I am curious about this as when you go to take these off are they prone to breakage when backing out etc etc. I searched the other forums and have not seen a great answer to this other than people warn about breakage and your screwed if itfalls into the block. Some insigt would be great as well. Lastly if you drop off at a mechanic (diesel) to do replacement do they usually warn against this or when it breaks off do they call you and say oh by the way the glow plugs were 72 and an hour of labor plus $1500 to remove he head when the plug broke off into the head.

Shane

[1987IDI]

My owners manual says to replace them once a year. Replace them when its gets harder to start at cold temps.

The owners manual also says that there is no need to plug your truck in at night until the outside temp reaches 0 deg F. So your glow plugs should be able to start the truck into the teens or single digits on its own.

I start plugging mine it at 30F just because its nice, but i started the truck last year at 5F without plugging it in.

When you change glow plugs, get each piston to the top of its stroke before you pull one out. That way if it brakes off it will stay in the pre-chamber and you can remove the injector and try to get it out.

Take them out slow and straight and chances are you will have no problems, its just a nice safety net.