How to Remove Broken Glow Plugs
Intro: How to Remove Broken Glow Plugs
The aluminum head 4 valve diesels are notorious for seizing glow plugs. Apparently the plugs don't seat properly at the combustion chamber end. This allows carbon to get packed in around the barrel. Over time the plugs become glued into place. The narrow neck between the hex nut and the threaded shaft isn't up to the task of untwisting the plug and it snaps off. The problem has nothing to do with the threads sticking, though the aluminum steel combination can't be helping.
If you have a broken off glow plug, you are faced with a choice:
A: Remove the head and take it down to a machine shop to have the plug machined out
-- OR --
B: Make a simple puller to yank out the plug.
This page describes how to do (B)
If you have a broken off glow plug, you are faced with a choice:
A: Remove the head and take it down to a machine shop to have the plug machined out
-- OR --
B: Make a simple puller to yank out the plug.
This page describes how to do (B)
STEP 1: Tools, Caveat & Initial Work
This instructable is based on my DIY page on removing glowplugs from OM606 heads '''HERE'''. As such, if you are pulling a different plug you will need to adjust the tools and dimension a bit. The basic method should still be valid.
Tools:
< no picture for this step ... sorry >
Tools:
- vice grips
- drill motor
- 1cm drill bit (13/32" is just right, 7/16" might be too big)
- M6 x 1.0 Tap and drill set
- hardened M6 x 1.0 bolt, at least 6cm long
- hardened M6 nut
- assortment of washers
- a 13mm X 3/8" standard depth socket
- patience, lots of patience, heads are very expensive replacement parts
< no picture for this step ... sorry >
STEP 2: Freeing the Threads
Drill out the threaded portion of the plug. Use a 1cm/.4" drill bit to drill the first 15mm of the snapped off plug. This gets you through the threaded portion of the plug. Now the plug can be pulled straight out, rather than needing to be turned. If you drill straight along the axis of the plug you will leave the threads of the plug in the head. The head will be undamaged. Blow out the chips.
STEP 3: Drilling the Body
Drill out the hollow part of the plug with the 5mm drill from the M6 Tap set. Go in at least 35mm and not more than 45mm, as measured from the surface of the head. Blow out the chips.
(All units measured for 24 valve OM606 engine)
(All units measured for 24 valve OM606 engine)
STEP 4: Tapping the Body
Use a M6x1.0 tap to make threads on the inside of the glow plug body as far in as the tap will go smoothly. Whatever you do, don't break the tap in there. Take your time. Blow out the chips. (picture shows larger tap, use a M6 for this step)
(Again, measurements relate to the OM606 24V)
(Again, measurements relate to the OM606 24V)
STEP 5: Building the Puller
Thread the M6 nut onto the M6 bolt. Then stack some washers on to the bolt and thread it as far as it can go into the (now threaded) glow plug. Just get it snug, no real force is required.
STEP 6: Pull the Plug
Turn the nut clockwise so that it gets further away from the bolt head. This will force the plug out of the head. The first real resistance will be firm. After the grip of the carbon gunk is broken it will move easier. Then it will stop moving. This means that the plug is jammed up against the washers. Unscrew the puller and pry out any bits (thread rings, etc) that are easily removable.
Reassemble the puller with a 13mm x 3/8" socket instead of the washers. The hollow formed by the socket will allow the plug to move further out of the head.
Reassemble the puller with a 13mm x 3/8" socket instead of the washers. The hollow formed by the socket will allow the plug to move further out of the head.
STEP 7: Success!
When the bolt head starts to turn, you will have pulled the plug out far enough that you can yank it out by hand. This is what you should see:
STEP 8: Cleanup & End Result
Suction out the chips. Then, insert some wadded up tissue paper into the hole. Now you can clean up or repair the threads. If you were careful the threads should be good and you can install a new plug. If the threads are damaged, install a Time-Sert or Heli-coil (M12x1.25 x 15mm). Remember to ream out the glow plug hole (Klann KL-0369-13)
As an experiment, I've chosen to coat the entire body of the plug with Hylomar HPF. Aside from sealing the nose and threads this sealant is fairly temperature stable and may fill up the space that would otherwise fill up with carbon. We'll see in 50Kmiles or so.
As an experiment, I've chosen to coat the entire body of the plug with Hylomar HPF. Aside from sealing the nose and threads this sealant is fairly temperature stable and may fill up the space that would otherwise fill up with carbon. We'll see in 50Kmiles or so.
54 Comments
inspecter gadget 2 years ago
The thread can be gently cut out when the drilling diameter and depth has been reached usually you can smell carbon or see a void between the thread and glow-plug shaft when at the right depth.
inspecter gadget 2 years ago
LinuxH4x0r 16 years ago
DaveS321 5 years ago
Diesel fuel can be slightly dearer than petrol in some countries but with around 50% more MPG, diesel works out a lot cheaper in the long run. The ONLY real thing to be careful of is to ensure that the car you want to buy has a good quality and working Catalytic Converter, not the cheap garbage ones that Fords have. Get a nasty one and it will smoke like crazy, chances are, it won't pass the next MOT emissions test. Even ticking over, give it a boot and see if it blows out lots of black smoke before you decide to buy it.
I have a 2001 Saab 9-3 2.2 TiD and emissions were 0.5 on my last MOT and I get around 55MPG on a run and 45MPG around town, not too shabby for an 18 year old 2.2 litre engine with 200K miles on the clock. The only main thing about a diesel is that you can't expect a performance car, I've see a 2 litre cranked up to 200BHP but most factory cars have about 120 to 150. However, they pull like a train and mine will poodle around all day in second gear, up quite steep hills as well, without even touching the accelerator. Even my petrol 2.2 SRI 150 Vectra I had before it would stall on a slight hill in first unlesss I put my foot down a bit.
In all, diesels are more suited to longer journeys and especially for towing trailers and caravans. Around town all the time, they can get choked up unless you give it a good run on the motorway occasionally to blow out the c**p.
Just be a bit careful on insurance, I don't know how these insurance companies decide on the insurance classes but you can end up with a far more expensive car for insurance than it really should be. Best to check the class before you buy one to be certain. My Saab 9-3 saloon is class 21 but the same year 9-5 which is identical in every way except that it has an estate body, (Station Wagon if you're American), is class 34. Go figure.
DaveS321 5 years ago
Maintenance is about the same. Diesel may be slightly cheaper than petrol but considerably more MPG which vastly offsets the cost. I got about 40 MPG on a run from a 1.6l petrol Nissan Bluebird but I get about 48 MPG from a 2.2l TID Saab 9-3. My 1.9l non-turbo Peugot 405 went 625 miles on 50 litres of fuel, that's 62.5 MPG!
Yes it has a lot more torque, you can usually pull away on a fairly steep hill without even touching the gas pedal. One trick I used to do patrols on a site with a diesel was to put it in second, pull away and let it pull itself around the site just idling, up hills as well, not much would stop it, in first gear, it would pull itself up a 45 degree incline without me touching the gas pedal with no effort.
But you pay for it in HP so acceleration is not as good. However, saying that, new diesel cars have a lot more acceleration than older ones despite still having less HP than their petrol counterparts. My 1999 Saab 9-3 TiD SE can match a turbo petrol 1.9 Peugot 406 for acceleration quite easily. A newer model 2.2 turbo Diesel could probably leave it standing.
ilikeadabox 13 years ago
iKill 16 years ago
LinuxH4x0r 16 years ago
iKill 16 years ago
LinuxH4x0r 16 years ago
leebryuk 16 years ago
BBC Article on UN
Linux, you are right that you do get more bang for your buck and diesel is therefore more cost efficient per mile driven.
Mepains point is sort of like saying that having a bigger gas tank is inherently worse because it costs a lot to fill up at each refill, irrespective of overall efficiency per mile traveled. By his point, you could "eliminate" the diesel cost disparity by halving the size of VW Jetta tank and therefore making it "cost less" per refill.
So, go feel free to buy a modern diesel and have a nice time. On the other hand, modern compacts (Honda Civic, Toyota Corolla) can achieve around 40mpg if they are driven by sane human people. My 2000 Saturn SC1 consistently (we are talking over years) had a personal mpg city 28/interstate 40. Use the cruise control judiciously while on the Interstate, pace yourself behind a slower line of cars and in town, don't accelerate quickly, especially if you are heading up to a stoplight again. Sit back and relax while you drive.
And purchase a standard (stick) transmission. It makes a big difference.
LinuxH4x0r 16 years ago
Besides, the UN is BS!
http://en.wikipedia.org/wiki/Rwandan_Genocide
UN sucks
tech-king 16 years ago
membrane 16 years ago
Here's a good example of a modern diesel it actually can outperform many gasoline cars.
You'll be very hard pressed to get 295lb/ft of torque in anything less then a big V8
let alone a 2.2l i4 gas engine.
http://www.popularmechanics.com/blogs/automotive_news/4246024.html
tech-king 15 years ago
membrane 15 years ago
tech-king 15 years ago
Esmagamus 15 years ago
leebryuk 15 years ago
Esmagamus 15 years ago