83 300D 617 turbo.
I need to replace the GPs on this thing. I'm not going to hunt for the bad one, 60 bucks they'll all get done. Two look hard to remove, #1 and #5. Are the GPs hard to remove? Any tricks or tips I should know about them before attempting this change? They have the appearamce of wanting to break off with too much torque applied. Remove them HOT or Cold?

Thanks for any advise.

Replacing the GPs on this car is a bit of a PITA. You can try it without removing anything, but I gave up on that and removed all the injector pipes. That made it much easier. Some plugs might rotate in place and not come out. You have to pull on them while turning them. When the plugs are out crank the engine for a couple seconds to blow out carbon out of the GP holes. If you're anal like I am you'd put the injector pipes back before doing this so that this dust doesn't end up stuck in your injectors. Other people clean their holes differently. Before installing new GPs lubricate the threads with something so that next time they come out easier. Oh, and do all this cold. No reason to have a hot engine for this, unless you want to burn your fingers.

But before you go ahead and replace all your GP's test each one with an ohmmeter through the adapter that supplies current from the relay. Chances are you only have 1 bad GP.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

The five glow plugs can be changed out in about 25 minutes, including cleaning the electrical connectors at each one with a razor blade.
I use a wrench on one and five, and a 1/4 drive ratchet, a 12mm deep socket and 10 inch extension on the others. Once you do it once, they can be done very easily.
Also, If I have to change them in the cold, I ike for the motor to be warmed up so as to help keep my hands warm while working on it.

I would say the time required to change GPs mostly depends on how easily they come out. If they're clean and lubricated you can just loosen them with a wrench, then unscrew them with your hand and be done real fast. My GPs were seized with carbon and it took several days of pain to change all of them.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

On the GP you use a wrench (not a socket) to take out, just loosen the nut, don't remove the wire or the nut. Then after the GP is out of the hole remove the nut and wire. Install in reverse order.

Its easier to do this way and there is much less chance of loosing the nut. Why don't new GP come with a new nut?

P E H

There's also the age-old recommendation to use anti-seize compound on the new glow plugs going back into the head.

There. I've increased my post count by one.



Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Oh, I forgot - a glow plug reamer is very useful in this situation. You clear out all the carbon in the immediate vicinity of your glow plugs. A glow plug without carbon packed all around it will get hotter faster.

Make that a 2-post addition to the count.

Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Pistons both suck and blow.
If the piston is on a downstroke it will draw into the precombustion chamber any loose carbon laying in the glow plug hole.
When a glow plug reamer is used GREASE is specified in the factor shop manual as necessary to be placed in the reamer vanes to catch carbon . I think that when reaming is necessary it is wise to pull the injectors and use a vacuum while the glowplug hole is open to be sure no crud is dropped into the precombustion chamber... because the pintle and small holes in the precombustion chamber must be clean for proper fuel usage.

rmmagow,

It is a lot quicker, less costly and easier to do a resistance check to find the bad GP than replace them all.

P E H

If a glow plug won't come out b/c of carbon build-up, couldn't you take out the associated injector and clean the last 3/4 of the glow plug easily and then be on your way?

Also, PEH, thanks for the previous injection tips about a week ago. The only thing I didn't realize was that by replacing the pressure valve o-rings, that my oil would get fuel in it - about 2 qts!! Luckily, I checked the oil before I started that car. Unfortunately, I had about 200 miles on that sybthetic oil I had just put in - what an expensive flush that turned out to be.
Cya,
Adam

At $8.00 a whack from autozone it was easiest ot replace the all.
I guess i was lucky none were stuck. But i had mine changed out in less than an hour.
If you're hamfisted or have really big hands I can see ths job might be a significant PITA.
Care is needed not to loose the small nuts. I found a needle nose visegrip usefull when the insualors would turn inside the housing.
Carefull tapping with a rubber mallet and 12mm box end wrench helped loosen the glow plugs initially. #1 needed a deep socket and 3/8 drive to loosen.

A fair amount of finnesse is needed to screw the little nuts back on especially on #5.

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Nothing in this world can take the place of persistence. Talent will not; nothing is more common than unsuccessful people with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan "press on" has solved and always will solve the problems of the human race.
Calvin Coolidge (1872 - 1933)

Axlechassis,

See my post about R&R GP nuts.

The last I asked about GP at AutoZone (maybe 6 months ago), they told me they were about $25 each. So I told them I could get them online for half that. What Autozone did you go to?

P E H

1 just bought 5 at my lcl AutoZone for 10.99 each - Bosch - not bad - here in MS

PEH:
I got my gp's at the autozone in santa fe, nm

The only trouble I see with leaving the wires on till you get the glow plugs out is you cant get a socket or box end wrench on them that way. I suppose a line wrench would work if you do it that way.

__________________
Nothing in this world can take the place of persistence. Talent will not; nothing is more common than unsuccessful people with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan "press on" has solved and always will solve the problems of the human race.
Calvin Coolidge (1872 - 1933)

Another post previously suggested doing this job right after doing a bottle of diesel purge. Apparently the diesel purge works its way ever so slightly into the first couple threads and makes removal easier. They do get stuck!! so this might be a wise measure to take just in case.

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"If anyone knows other lessons I need to learn, please tell me. I'm tired of learning them the hard way".
by JerryBro

The Glow Plug Wait: This waiting period is a moment of silence to pay honor to Rudolph Diesel. The longer you own your diesel the more honor you will give him". by SD Blue

My normal daily life; either SNAFUed- Situation Normal... All Fouled Up, or FUBARed- Fouled Up Beyond All Repair

62 UNIMOG Camper w/617 Turbo, 85 300SD daily driver- both powered by blended UCO fuels