I know this will ruffle feathers but I am not a fan of R&R the glow plugs just to see if they are stuck or not. My philosophy is this...don't touch them until they need replacement then replace only the one(s) that need it. It's unclear to me that time/mileage is the deciding factor in whether they are seized or not. In other words...I'm not convinced that a glow plug will not be stuck after, say, 2 years but will somehow get stuck after 4 or more. So I don't see the point in taking them out and putting old ones back unless you are convinced that time is a factor.

I'd leave well enough alone. R&R of old ones seems an un-necessary risk of encountering a seized plug or two now that you may not need to deal with for years. To those of you who would say this is just living in denial, I guess I'd say all of car maintenance is staving off the inevitable...but I just don't see looking for trouble here.

When I bought my '98 I changed all the GPs as PM...in hindsight that was very risky and if I had known then what I know now I would not have done it. Mine were all originals and came out without too much trouble after 7+ years so it probably wouldn't have mattered if I had left them in there another year or two or as long as it would have taken for one to fail. Now I know the ones in there have 2 years on them, and I don't plan on touching them until it is absolutley necessary...even then I only plan on replacing them as they go out...not all 6 at once again.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz