Use a timesert. If the hole is hogged out too big for the timesert, use a Bigsert. Don't use a helicoil. This is an easy repair.

If you're not comfortable performing it yourself, any machine shop should be able to do it.

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

I was looing on eBay they have this listed: Glow Plug GLOWPLUG Thread Repair Inserts M12 x 1.25mm Pack of 5 for total cost of about $21. However it is just the inserts not a tool kit.
There is also inserts for other sized glow plugs.

There is also several Tool Kits for diffrented sized Glow Plug tread repairs: Glow Plug Cylinder Head Metric Thread Repair Restorer Tap Kit M12 x 1.25, $50+
"Description

Professional tool for commercial or occasional use

Glow plug Thread repair kit M12 x 1.25

Suitable for repairing the glow plug mounting thread in the cylinder head

Fast and effective remedy for damage to cylinder head glow plug threads

Unique assortment for the repair of worn or damaged threads

Provides absolute firm and gas density seat for many uses

This kit ensures a straight thread and new insert provides an efficient fit

Essential kit that solves common problems on diesel engine alloy cylinder heads

Set includes tools for the precise insertion of threaded inserts into the head and features a unique tap guide system to ensure their correct alignment

Essential tool for alloy cylinder heads"

__________________
84 300D, 82 Volvo 244Gl Diesel

I was looing on eBay they have this listed: Glow Plug GLOWPLUG Thread Repair Inserts M12 x 1.25mm Pack of 5 for total cost of about $21. However it is just the inserts not a tool kit.
There is also inserts for other sized glow plugs.

There is also several Tool Kits for diffrented sized Glow Plug tread repairs: Glow Plug Cylinder Head Metric Thread Repair Restorer Tap Kit M12 x 1.25, $50+
"Description

Professional tool for commercial or occasional use

Glow plug Thread repair kit M12 x 1.25

Suitable for repairing the glow plug mounting thread in the cylinder head

Fast and effective remedy for damage to cylinder head glow plug threads

Unique assortment for the repair of worn or damaged threads

Provides absolute firm and gas density seat for many uses

This kit ensures a straight thread and new insert provides an efficient fit

Essential kit that solves common problems on diesel engine alloy cylinder heads

Set includes tools for the precise insertion of threaded inserts into the head and features a unique tap guide system to ensure their correct alignment

Essential tool for alloy cylinder heads"

"SET INCLUDES THE FOLLOWING

• Reamer for reaming original thread
• Taps for threaded sleeves
• Taps for trimming the original thread
• Assembly tools for inserting the threaded sleeves
• 5 x 12mm length threaded sleeves (inner thread - M12 x 1.25) (outer thread - M14 x 1.25)
• 5 x 19mm length threaded sleeves (inner thread - M12 x 1.25) (outer thread - M14 x 1.25)
• 5 x 26mm length threaded sleeves (inner thread - M12 x 1.25) (outer thread - M14 x 1.25)"

It comes with some of the insert threades sleeves.
Amazon or other places likely sell similar kits

What I see that I like about the kit is that the tools have pilots on them to center the tools in the inner glow plug hole (the part the tip of the glow plug goes through). Having pilots on the tools makes it easier for someone who has never dont it to be successful.

__________________
84 300D, 82 Volvo 244Gl Diesel

Thanks all for the support. The saga continues. Will update as I go forward.

__________________
Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

I have used Timesert and can vouch for it. Each size kit comes with the tools needed for that size, the reamer, the bit,the tap and guide and of course the tool to insert the Timesert. It was quite easy to do, although I did not use it on a glow plug hole. I would probably do it without removing the head, you could drill with a shop vac rigged up then put grease on the tap to hold the shavings. I did not hesitate to buy the kit as it was cheaper than letting a shop do it plus I have leftovers in my tool box now if I ever need another fix. And I am a tool addict anyhow.

__________________
Brian
87 300Dturbo 180K #14 head still running R-12 SOLD 12/2017
02 F350 Powerstroke 180K
05 Chevy Express 1 ton w/Royal Utility box 120K
08 Infiniti FX-35 40K
15 Golf Sportwagen TDI 35K
10 Sprinter 3500 chassis with a Class A Winnebago on it. 56K

Generally you can fill the grooves/flutes of drill bits and Taps with grease and that will trap the metal chips in the grease.
However, you need to turn the drill bit slowly so it does not heat up and melt the grease.

There is a bunch of Kits to rethread damaged glow plug threads but I would pick the kit that has the pilot rods on the taps and drill/reamer.

Personally I have a lot of trouble drilling a hole straight in the direction I want to go and that gets worse if I am at some odd angle or there is little room in it. Also Aluminum can be sort of grabby when you drill into it.

The kit with the pilots has a reamer that you turn by hand and do not have to use any power tools. That hand turning allows you a lot of control you would not have with a Drill Motor and Drill Bit.

The Glow Plugs seal on an angled shoulder. If the hole and/or threads are off center there is some chance it may not seal. I don't think that is a really big deal as you can get a small Copper Washer and use that between the sealing area and the head to seal. But, it is nice to not have to do that.

__________________
84 300D, 82 Volvo 244Gl Diesel

i see what you mean... getting that drill hole nice and straight would be critical

http://www.peachparts.com/shopforum/diesel-discussion/235397-om606-glow-plugs-dont-know-whether-laugh-cry-3.html

post #42. looks like he's using hand tools for the reaming, the threading and the insertion.

don't see what he used to enlarge the original hole in step one.

__________________
Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

In the thread you posted is a pic of the Kit. It has a Drill Bit which has a square end on it like you are supposed to turn it by hand with some sort of Tap handle.
You could do that with Aluminum but it would of course be slow. But, that does not guarentee it going in straight.
There is some youtube viedos on doing the job with various tool kits.

__________________
84 300D, 82 Volvo 244Gl Diesel

Thank You , GPS

__________________
'84 300SD sold
124.128

Job done!!!
Decided on taking my chances on fixing it myself with the timesert. Worked perfectly got everything put back together in about two hours total. My helper/the car owner got a picture of me hunched over it checking everything out right before we fired it up about midnight last night

Attached Thumbnails

 

__________________
Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

Perfect.

Did you use a Drill Motor or turn the Drill Bit by hand?

__________________
84 300D, 82 Volvo 244Gl Diesel

nicely done,

I love it when this DIY stuff goes smoothly.!

__________________
1983 300CD Turbodiesel

I used a battery drill. I wanted to use the hand chuck gripper tool I bought but the drill bit from the timesert kit was too big to fit. The other tools fit in it fine. Drilling it was about the most nerve racking part but access was perfect and i just went slow. No problems.

__________________
Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

congratulations !

__________________
'84 300SD sold
124.128

Thanks.

__________________
84 300D, 82 Volvo 244Gl Diesel