Glow Plug Seating

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
In all the years of repairing stripped or stuck glow plugs, I think some improved method for installing properly is in order. Not to take away from what has been said previously for proper torque and use of an anti-seize, being careful to not cross-thread, we still see many gp's that ruined the threads in the cylinder head.

One of the things we think causes thread damage and stuck glow plugs is a poorly seated gp that has exhaust gas blowing soot up into the threads. Over years, the accumulation will cause the threads to deteriorate and the soot will pack into the threads making them very difficult to remove.

In order to properly seat the gp, first, we use a 10 x 1.0 tap to clean the threads of the gp bore. Then with a properly cut 11/32" drill bit RUN BACKWARD, We scrape the carbon from the seating area for the gp. Here is a picture of a modified drill we use.


And another picture showing the matching angle against the glow plug itself, which is a 55 degree angle.


Remember, the drill must be relieved aggressively and can ONLY BE RUN IN REVERSE or you will cut into the seat, damaging it.

When the seat is clean, you will see about an 1/8" circle shined up where the gp contacts. With the gp seat cleaned like that, there should be no leaks and no carbon build-up in the plugs.

As always, we recommend the use of an anti-seize. And we replace gp's when they stop working. We often see people replacing sets. My question is:
When you have a light bulb burn out in your house, do you replace all of the light bulbs? Why not? Because it would be expensive and foolish to replace them all, when you don't know how long they will last. So, what's the difference? Some gp's last 50k, some last 250k.
 
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JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
When you have a light bulb burn out in your house, do you replace all of the light bulbs? Why not? Because it would be expensive and foolish to replace them all, when you don't know how long they will last. So, what's the difference? Some gp's last 50k, some last 250k.
Maybe this makes more sense with the common rail plugs that are expensive because of the dual purpose they have.

ALH glow plugs are not that expensive...even a good brand like Bosch.
If a customer has one burned out and does not know the last time they were changed or knows that they have ~100K on them, I suggest that they change them all.

A faulty glow plug will leave a DTC that must be cleared with VCDS or scanner, etc... Why not start from scratch so that they are not dropping off one by one a few thousand miles apart. It can be a pain to a lot of drivers that don't have the means of clearing codes just to save $15-30 a piece. And, quite often I see mismatched sets of different brands of plugs that heat differently and just degrade the system's operation.
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
Marty,

I guess that's just the VW cheapskate in me talking. I check ohms and match impedance when replacing less than a set. I still think glow plugs and light bulbs stop working at widely varying rates. I agree that changing one or more-than-one is an individual consideration.

Dirtride,

I'm looking at making at custom chamfering tool from drill rod blank. I'll let you know how it comes along.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
I give the customer the option if there is just one that is bad. Because so many times, they come in with the only complaint of "the MIL is on", which of course could be 50 different things. If you replace one plug, and two weeks later, the MIL is on again, the knee jerk reaction to someone that doesn't know any better is "they did not fix my car correctly", even if now it is another plug that has failed.

If there are two or more bad, then we generally sell all four. More common on the ALHs, especially the 2001 and earlier style which due to the way the voltage is handled (ON or OFF) is harder on the plugs anyway.

On holes that are badly carboned up, for whatever reason, I use X66 spray and let it sit, then a soft brass brush on a drill, gets it shiny clean. I also have a thread chaser if necessary, but it rarely is.

The thing that really messes the head up are the use of non-OEM brand plugs, especially Champion, because the angle of the seat is not correct, and they never seal properly. Bosch, Beru, and Bremi all work fine.
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
i like the drill bit idea, below is what i use


modified beru plug with three small "flutes" cut with a dremel... chucked it up and spun it in my drill press while filing the threads so it can free spin in the plug bore



showing the now threadless shank


the two glow plug bore cleaning tools i employ... not shown is a 10x1 tap embedded in a 1/4 drive socket
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
how did you cut the drill bit? How did you verify that the angle was correct, that small of a size is easy to get a 56* or a 53* all the same and not be able to tell. I love jimbot's idea, i would do this over a drillbit custom mode unless it was done in a machine shop on a lathe
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
I like Jimbot's idea too. It's simple enough. Thanks for sharing.

As for getting the angle right, if it's not in the tooling, it's all by eyeball. Test cuts to assure seat cleaning, may require changing the angle slightly.

Seriously, if you were off 4 degrees, I don't think it would make much difference.
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
Walmart
44 caliber gun brush

EDIT:
38 caliber will be closer to glow plug diameter.
 
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Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`


After some consideration, I modified my tooling. Mostly, because drill bits that are 11/32" are more expensive than what is necessary to make this seat cleaner.

Here is the tool I created from drill rod. It's not fancy, doesn't take much time to make and is water-hardened tool steel. The cutter can be attached to a drill and in 5 seconds, it cleans the counterbore very nicely. It's not really a cutter, but deburring tool.
 
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jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI


After some consideration, I modified my tooling. Mostly, because drill bits that are 11/32" are more expensive than what is necessary to make this seat cleaner.

Here is the tool I created from drill rod. It's not fancy, doesn't take much time to make and is water-hardened tool steel. The cutter can be attached to a drill and in 5 seconds, it cleans the counterbore very nicely. It's not really a cutter, but a scraper.
looks good !
 

J.P.

Veteran Member
Joined
Aug 14, 2007
Location
Northern MI
TDI
Black 05 b5.5V/6spd w/274k miles (daily). Silver 02 Golf/5spd w/240k miles (fun 1). Mint Tornado Red 01 Golf/5spd w/440k (ALH still perfect!!!).
Any method to keep the carbon / soot out of the cylinder?

What method do you use to clean the soot / carbon build-up in the bore? Do you do something to prevent any from falling into the cylinder? Or not worry about it as it is soot / carbon.

To keep debris from entering the cylinder I've put an earplug in the bore for cleaning the threads with a back tap, but the opening into the cylinder is much smaller.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
What method do you use to clean the soot / carbon build-up in the bore? Do you do something to prevent any from falling into the cylinder? Or not worry about it as it is soot / carbon.
To keep debris from entering the cylinder I've put an earplug in the bore for cleaning the threads with a back tap, but the opening into the cylinder is much smaller.
Either Plug the hole, like you said, OR just rotate the crank until the intake valve is open, and put a leaf blower into the intake so it blows air up though the hole your working on. works like a charm.
 
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