Oops, think I cross threaded the glow plug hole

I replaced all but the last (fourth from the left) glow plug. I felt plenty of resistance and it would not go any further. The nut on the glow plug was eaten. What should I do now?
I can see why it happened. There is very little room to install this glow plug.
Thanks.

This can quickly turn into a nightmare no mattter which path you proceed on at this point.

One thing I can tell you is that any Glow Plug(GP) will come out easier on a fully warm engine (190*F) than on a cooler engine. Working on a hot engine isn't easy but when it comes to GP's ....a hot engine is your friend.

You can try a liberal application of "PB Blaster" penitrating oil.
You'll also need a 1/4" drive universal swival joint and a 10 MM 1/4" dr deep socket with an extention. These tools will let you get the socket "straight" onto the GP.

Befor you apply the PB blaster use a little compressed air to blow away any debris around the base of thr GP.
Apply the PB blaster and start the engine again...just to keep things warm. Then give it another small application of PB blaster. Shut down the engine and try removing the GP with the tools that I've mentioned.

The worst case situation is a GP broken off in the head which will require the head to be removed and taken to a machinest to have it removed.

If the GP does come out... You'll need to run a tap to re-thread the GP hole which isn't that difficault to do.

You'll have to have it heli coiled if you know of a good garage or engineers shop , they will drill it out with out getting any swarf/ship in there then a blank then re-tap it job done.

Be VERY carefull about heli-coils. There is a thread here on the forum with some nasty photos...where the end spur of the heli-coil broke off...thus resulting in a piston which was distroyed. You could clearly see the imprint of the end spur of the heli coil imbedded into the head of the piston. This was done while the head was still installed on the engine. The heli coil installation was "by the book" but the end-spur of the heli-coil killed the piston.

I'll try to locate the thread so the photos can be viewed.

An alternative to Heli-coil is a "thin-sert"
Thin Cert

Thanks. I managed to get it out. What I need is the universal joint. I already have the 10mm deep socket and extender. I will see if I need to tap the hole. Should I be too concerned with some metal filing falling in?

Its not a problem if they have the right equipment and the right person is doing the job , like most things i guess.

I have seen tapes made especially for this. They stick all the way into the head, then you adjust them to expand out to fit the threads and chase the threads from the inside out. Put some grease on the tap to catch any metal.


Never had to try it though. I don't work with spark plugs or glow plugs.

Is a gp thread m10-1.0 or m10-1.25 ?

M10 x 1.00

Yuri.

Thanks... Merry Christmas.

I am having a hard time finding a source for a M10 x 1.0mm thread tap.
Anyone know where I can order online or pick one up?
Thanks

ymz said:

M10 x 1.00
Yuri.

Click to expand...

Anyone?

TDI Nut said:

I am having a hard time finding a source for a M10 x 1.0mm thread tap.
Anyone know where I can order online or pick one up?
Thanks

Click to expand...

Try talking to your local motorcycle repair shop... I believe that the spark plugs have the same thread...

Yuri.

About the tap...I believe we picked one up either at a local Napa auto parts, or possibly a machine tool parts store.

Where to find a M10 x 1.0 tap???
Automotive parts store
Motorcycle parts store
Granger - Industrial supply www.grainger.com
Mc Master Carr - same as Granger, an intustrial supply store
If you know someone in the machining industry they could provide local tool supply vendors.

Hey guys, I just bought a good heli coil kit. I have a stripped thread on glow plug 1. I tried the heli coil as a practise run on an aluminum piece and it worked great the first try.

I'm about to do this on my 1.9 tdi engine. Can anyone recomend anything or any tips before I start drilling the block with a 13/32 bit?? I'm thinking of inserting a piece of cloth or something down the glow plug hole just to avoid anything going into the head.

Any tips are much appriciated.

Thanks

Definitely stuff something into the glow plug hole below the threads!!!

See http://forums.tdiclub.com/showthread.php?t=221087 for more precise details...

Good luck !!

Yuri

Yes, you definitely have to plug the hole. Some folks use a sponge-type ear plug that expands. Also, after you are done assume some shavings have entered the combustion chamber. Make a small attachment (like a plastic straw) that is duct taped to the end of a shop vac to suction out the chamber through the glow plug hole.

Be very patient when doing the heli-coil. Remove everything you can to gain good access. Make sure your new heli-coil threads are at the proper depth compared to the original thread location. Finally, do not touch your drill bit to the seat of the glow plug hole. This has a specific angle to the recess that you don't want to damage. Take a look at the shoulder at the bottom of the glow plug near its tip to get an idea of what I am referring to. You can use a glow plug for reference as to the depth of some of these landmarks.

Good luck,

Thanks guys, I've read Franks thread a few days ago, I only doing this to plug one which has easy access. I think I can pull this off, my only concern was the depth of the insert, but thanks for the glow plug guide tip never tought of that.

Would it make sense to compare the glow plug to my tap side by side and mark on the tap where the glowplug thread ends that way I know exacly how deep to tap? I'm only saying this because this is what I understood from franks guide.

vili19 said:

Would it make sense to compare the glow plug to my tap side by side and mark on the tap where the glowplug thread ends that way I know exacly how deep to tap? I'm only saying this because this is what I understood from franks guide.

Click to expand...

Yep, this is exactly what you do.

Just an update, I managed to screw up my engine block. I drilled the 13/32 hole way off it's notrmal position, I did put the helicoil in but the gp sits tottaly bent to the right, I have compression loss and when I spray soap around the plug its bubbling. Car bearly starts.

Is there anything anyone can recomend to seal the air coming through or am I looking at a new engine? Car is at 300xxxkm it's still running strong when started of course.

To those who have never done this before be very carefull, and dont do what I did.

Sound like you did the same thing I did. I had to replace my cylinder head. Here are the links: Cylinder Head Replacement due to Glow Plug Horror

My decision was easy since the car had no rust and was in excellent condition and relatively low mileage. I was willing to put in the necessary work. But, it isn't a cheap project. Although, it certain was cheaper than buying another vehicle of equal quality.

I guess you need to evaluate how long you anticipate having this vehicle.

I was fortunate to find someone selling a brand new VW cylinder head for a very reasonable price. You many want to send a PM to Frank06. He does excellent cylinder head work and can likely give you some wise guidance as to your best plan of attack.

Good luck.

Thanks, Paul, well I found an engine with 200xxx km's for 1300 bucks. The floor on my jetta is immaculate and there is bearly any rust on the car, I'm thinking a swap would be my cheaper route. I have pretty much all spare parts I can use for the future on this engine.

Just courious would anyone recomend putting that jbweld stuff for a temporary fix to seal the gap??

vili19 said:

Thanks, Paul, well I found an engine with 200xxx km's for 1300 bucks. The floor on my jetta is immaculate and there is bearly any rust on the car, I'm thinking a swap would be my cheaper route. I have pretty much all spare parts I can use for the future on this engine.

Just courious would anyone recomend putting that jbweld stuff for a temporary fix to seal the gap??

Click to expand...

No. The compression would blow it out (you would also risk some getting in the chamber upon initial application). Change the head .....