Glow Plugs

[MM9135]

I feel that this has been covered before but I was unable to find in the search. I am still learning about diesels.

My question is, should glow plugs be changed at regular intervals like spark plugs or are they the type device that could last for the life of the engine?

I own a 1996 6.5L GMC 3500 with 98,000 miles. The plugs appear to be original. They are working fine and the engine starts right up but I am a PM type person and like to catch a problem before it happens. :D

[DieselDavy]

MM9135,
Where is Georgetown, IN? I'm from Ft. Wayne.
As for Glow plugs, I never change them until they need it. You'll know, rough or uneven starts. I have replaced many over the years, trust me, MANY. But I have not changed a single one since I installed John Kennedy's Fast Glow plugs. Even with shipping, they are right at what I would pay locally for the current ACDelco G60s. They heat up quicker and can tolerate extended glow time. I have a pretty wore out 6.2 I use for a daily driver and I need more than twice the normal time in the winter to get her started. John's Fast Glow plugs have been in her for around 3 years and I've not had one fail yet. I have a set in another GM diesel also. I took out some good ones in that one just to get the Fast type in there. They work great! IF and WHEN you have starting problems, Call John!
Dave

[ucdavis]

If you have the old AC-9 plugs, I would change them out for Kennedy's (I just did that on mine). If you order up some of the old articles (click Join Us, then scroll down & click on each year of reprints to see what articles are included) Jim Bagley did a GP test that is interesting. The AC-9s (and the Lucas & maybe one other) could distort or even have the tip break off in the prechamber. The current AC design & Kennedy's won't do either. AC-11's won't distort/break, but they are not up to extended glow cycles for areas subject to ultra-low temps in winter that Kennedy's are.
Supposedly '95 and later all came w/AC11's, but mine were the older AC-9s. As a minimum, you may want to check what model you've got now.

[MM9135]

Thanks both of you for your input. Yesterday was the first time I had ever laid eyes on a glow plug and I was surprised to see how small they were. That brings up another qusetion. How easy are they to strip out or break off? It seems everything I do to this engine turns out to be a bigger job then the last. Being a van makes for zero clearance in many places. :(

Dieseldave, Georgetown IN is off I64 at the other end of the state from you just west of New Albany and 15 miles from downtown Louisville KY.