I have received a shocking number of calls in the past month, from new owners installing glow plugs that function once and die.

Everyone needs to be aware:
* The glow plug is NOT solid steel.
* The threaded glow plug wire stud is delicate.
* The electrical stud is directly connected to the heat element.
* If the threaded glow plug electrical stud twists, it will damage or break the heat element.

Please study this picture, before installing new glow plugs...









NGK - Defects - Metal rod glow plugs



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Thanks Hunter . . .ah, the need for some to over tighten things - this should save many people (and glow plugs) head aches. Betcha I have killed a few this way -

That is a great cross section pic Roy !!
It will help members understand how GP's work.
May even help get rid of some of the GP myths that appear from time to time.

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NGK - Defects - Metal rod glow plugs ???????

Are you saying this is a defect in the NGK glow plug design? AFAIK, Bosch, Beru and everyone else who makes glow plugs has a similar design. The problem is overtightening the 8 mm nut as if it were a mechanical fastener. With rust setting in, it spins the center electrode and breaks the continuity of the filament ( same as a burned out glow plug). All that's needed is a good electrical connection, probably less than 1/2 ft lbs is all that's needed on that 8 mm nut. Anti seize will help subsequent removal also.

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When I'm working on delicate items, I move my hand closer to the pivot point on the ratchet or wrench. This lowers the torque and, although more difficult for me, at least I know I won't damage the item.

Probably why they are in such a tight spot too!

Great info!

Excellent picture Roy! I have never understood much about the updated plugs but that helps a lot.

Ah, semantics and the literal interpretation of words... "Defects" is the word used by the website, and Roy copied this accurately. Knife and gunshot wounds to a human body are often described as "defects" in court, but nobody is saying that he victim was 'defective.'

Perhaps a more more familiar word would be "damage." Indeed, the French and German language version of this word translates to "damage."

In any case, several types of damage, or "defect" to glow plugs are displayed and can help in diagnosis of problems, or "defects" in operation.

I use one of these gear wrench adapters without the wrench. similar to your idea about moving to the pivot point.



I use the set of adapter more without the wrench then I do with the wrench. they work great to spin smooth sockets when you have greasy hands (I call them mercedes love hands )

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Reminds me of my Dad's sayings-"If it cannot be tighten with a wrench, or fixed with a hammer...you have an electrical problem."

i've always tightened new gp's to 12 ft/lbs. also ream hole with carbon reamer before installing, and use tiny amount of copper anti-seize on threads (do not use aluminum anti-seize on these ever!!!)

never had any problems with them myself, including changing them on 606 heads.

for new members