OM 606 Drilled too deep trying to extract a stuck Glow Plug
 

Hi Guys.

I know stuck Glow plugs in the 606 has been discussed endless. But here is a new one:

As the title suggests I drilled too deep when trying the extraction process. I was following the method where you tap the body of the GP so you can install a hardened bolt into the body and slide it out by tightening a nut down the bolt. But I never got that far.

When I was drilling out the center of the GP, I must have went right through the tip on the GP. I went so deep that fuel started to flow up into the Glow Plug chamber. What is behind there? Did I just completely ruin this head, thereby ruining this car?

By the way GP still stuck in there. The tap/bolt puller method didn't work for me.

Thanks in advance.

you would have had to drilled through the aluminium head material to hit the injector. even then, not much fuel would come out and i would have been very difficult to drill through.

more likely, and much more seriously, it may have been coolant!


Pull the injector. thats only reasonable next step after checking with a good light source if you can see the "mixing' ball in the prechamber through your drilled hole.

Ouch. I'm not sure what is in line with the glows on the 606, but are you sure it is not coolant?

I'd guess you can put a fork in that head...unless you got lucky and drilled into one of your injectors?

Im almost 100% sure it's fuel.

Now you guys have me doubting myself. I certainly know the difference between diesel fuel and antifreeze. But the entire garage had already stunk of fuel, PB Blaster, WD 40, etc from doing this. When I drilled through too deep and the fluid filled up the GP port, I went with the assumption I drilled right thru the tip of the GP and I saw fuel.

But I guess it is possible I wasn't drilling perfectly straight and went through the wall of the aluminum head.

Let's stick with the assumption it is fuel. If that is the case, what is just beyond the tip of the GP? Because at this point I am thinking of retreading the port, plugging it up and run on just 5 GP's.

My concern with this is that clearly fragments of the GP (metal shavings, broken ceramic tip, etc) will be left in there, If I drilled straight back too deep what else could I have damaged? Will these fragments fall into vital areas of the engine like the cylinder, pistons, etc?

I would pull the injector to find out. At minimum, you can find out if the glow plug tip is still in there.

There is not enough fuel available in the injector to fill up the glow plug port. It would have to fill up the pre-chamber and the cylinder before it flowed out of the GP hole.

The injector is made out of steel. Not sure of its Rockwell hardness, but pretty sure you would have to put some 'umph' into your drilling to go through it. Even if you hit the injector, there's a tiny amount of fuel in it, and even if the fuel could "flow" through it just sitting there, not sure there's enough in the line to somehow weep downwardly, although gravity would certainly move whatever fuel from high to low. Take a paper towel to sop up the fluid and then do a smell test. I agree a little bit of diesel or other similar fluids can stink up the garage where everything stinks like diesel, especially once it gets atomized and in the air.

I don't think the injector is inline with the glow plug.

Beyond the tip of the glow plug is the opposite side of the pre-chamber and then the head casting. If you could drill through the pre-chamber wall, you would hit coolant.

You can easily tell if you drilled through the glow plug with a gauge ruler made out of a chopstick from Chinese takeout, lining your measurement to a glow plug on the bench.

Ugh. It's more than a 'little' fluid. I guess I am mistaken and I really stuck coolant. So head is shot if that's the case? Can't just plug up the hole and run it on 5 GP's?

I will pull the injector and do the smell test to double check. But it sounds like you guys have convinced me.

If the head is shot I am going to just sell the car for parts at this point. I have no one to do a head replacement for me and if I can't even handle changing some GP's, I certainly am not going to try and tackle a head removal.

Coolant in the combustion chamber means you can't run it. If coolant is coming out of the glow plug, it is also filing the cylinder and draining past the piston into the oil.

:(

Per dimensions of the glow plug in this ebay listing New Genuine * TRIDON * Glow Plug TGP For Mercedes Benz E300 D E300 TD W124 W210

28 mm is the portion of the tip that extends into the pre-combustion chamber, from the flare to the glow plug hex (assumed where it snapped off) is about 2 x 28 mm. 56 mm is 2.2 inches. Did you drill more than 2 inches deep?

I'd find the best machinist around and pay him to come look at it. They have some pretty cool repair kits for similar situations to this. Don't for a minute think you are the only person who has done this (whatever it is).

I cannot see any source of a lot of fuel except your injector return or supply lines. Could it be running down from above?

My thoughts go out to you .I did a job on my Granada v6 once .. I had a leaking freezz plug that was weeping .It was going in to the engine as i was removing it .So i put a small 1/16 hole in it to screw in a self taping screw,to use it to pull it out with .Well i did it went right in the water jacket of number 6 cylinder.So head off was the only way out. Bite the bullet and remove the head . It looks to me , that diesels are a pain in the butt.

^^^Two comments I was hoping not to hear.

Sounds like it was just about that length.

I would verify before doing anything drastic. Blow compressed air in the drilled glow plug. If it holds pressure, you only have a glow plug to remove. Otoh, if you get bubbles in the coolant tank....... my condolences.

Thanks for the suggestion. But I don't have the time, means or funds to go where this route would lead me. Time to say goodbye to her and hope someone with access to a machinist or a means of replacing the head can keep her alive and running. :(

Going to miss this car.

I would love to get this car, as I think I can fix it whatever the problem is. However, I might as well be on the other side of the planet being in CA!

Do not crank the engine until you have ruled out breech of coolant jacket. potential hydro locking!

If I had done this, here would be my "on a super tight budget, need to get her running with nothing much to lose" attempt:

1.) Thread GP and remove.
2.) Inspect with $8 USB inspection camera
3.) If there is a hole in the head into the coolant passage, drain coolant.
4.) since GP is now removed, the ID of the hole is now significantly larger than the drilled hole diameter.
5.) Look at a drill and tap chart and select a common tap that matches the hole you punched into the coolant jacket.
6.) Hand tap the hole into the jacket.
7.) Degrease the threads, install a set screw with lots of threadlocker (heat resistant type? Coolant on one side of the screw should help keep it intact?)
8.) Let it cure, refill with coolant, pressurize cooling system, inspect with camera for leakage.
9.) if no leaks, button it up and hope for the best!

I'm not a machinist, just an engineer that gave it a little rent in my head last night...so take with a grain of salt.

This is a very interesting suggestion. But a few things to note:

#4 - GP is still not removed. It may be virtually gone by way of me continually drilling with larger and larger drill bits at this point. But I haven't actually removed anything other than shards and shards of metal shavings.

#6 - Do you really think this is possible? I mean taps are short. There's barely any room to work in there as it is. And based on comment above, I apparently drilled over 2" into the head. I mean I couldn't properly tap the center of the GP. I don't trust my skill set to tap into those depths.

I like your thinking and I am intrigued. I'll try anything.

First, drain the coolant ASAP to keep it from slowly leaking into the oil pan.

Grab a borescope from Amazon prime and have a look inside.

Amazon.com : 2 In 1 Smartphone USB Endoscope Inspection Camera, CrazyFire® 5.5mm Android Borescope USB Inspection Camera, Waterproof OTG Micro USB Borescope Inspection Camera with 6 LEDs and 5m/16.4ft Cable : Camera & Photo

You can get long taps:

Union Butterfield 3306E(UNC) High-Speed Steel Thread Forming Tap, Extra-Long, Uncoated (Bright) Finish, Round Shank With Square End, Bottoming Chamfer, H9 Tolerance, 4" O'all Length, 3/8"-16 Thread Size: Amazon.com: Industrial & Scientific

These are the screws I was imagining:

https://www.fmwfasteners.com/products/3-8-16-x-3-1-2-socket-set-screw-cup-point-alloy?gclid=CNC93paMh8wCFYeUfgodYIYP3A

Have you tried a leak down test of the glow plug first? It's easy to do and will tell you instantly if you have breached the coolant or not.

If anything, take a deep breath and take your time with the solution. Anything can be fixed, and many "holy sh&* moments are readily fixable and no big deal.

renaissanceman - TY for the tips and the links. I will consider this as an option. I have an Apple phone, but I can find a comparable borescope now that I know what I am looking for.

I don't know what this is.

You apply compressed air into the drilled glow plug and look/ listen for bubbles in the coolant expansion tank.

So, regards the GP drillout; is a helicoil installation, part of the possible plan going forward?

At what point do you, (generic you) go with a new head assembly?

Just trying to explore your ultimate options going forward on completely solving this job.......

depending on where this thing broke off (I think the threaded portion came out, leaving just the long shaft on the GP?) would depend on whether the threads would need to be reconstructed.

I'm going to venture a guess and say that a leakdown would be pointless...if there is coolant pouring out, the jacket has been breached. At this point the injector needs to be pulled, and a scope inserted through both the GP and injector holes to asses the damage. From there, post up the pictures and we will all mull over the best solution.

If the only alternative to an unconventional repair like I detailed is replacing the head, which the OP says is not an option, then we should get creative! If nothing else, we will gain knowledge of what the options for repairs are as this type of thing becomes more common as more GPs fail in the 606 engine out there.

Let's define ASAP. My drill aggressiveness occurred Yesterday Morning (Sunday). It's been over 24hrs, and realistically I won't have time to touch this thing again till Saturday. Is that too long?

If I am courageous enough to attempt your method I will just change the oil if that set screw plug holds pressure.

As far as draining the coolant. Will it be sufficient enough to pull the radiator plug? Or do I need to pull a plug on the block too (Does this car even have one?) If so, I need to find that.

I would remove the block drain plug, TODAY... it's likely the coolant is only leaking out the drilled hole, not into the pc... or piston... your best bet is draining the coolant and when time allows investigate further solutions with the damage.

Well, Assuming he drilled through the wall of the GP bore and breached the cooling jacket there...I was assuming a hole drilled through the GP tip, through the other side of whatever wall is opposite the GP (it would be through the opposite prechamber wall on my 603...)

Drain the radiator and the block. I'm thinking the block plug will be on the passenger side of the engine about halfway back where it is on my 603.

I notice that no-one has mentioned this so far, but if you have drilled through the glow plug into the prechamber, I would also be concerned about what metal chips have made their way into the engine...

The OP said it was fuel that was coming out, he did not say it was coolant. I am surprised people are against verifying how far he drilled and what fluid it was that was coming out. It's so easy, just stick a rod smaller diameter than the drill used in there and see how far it goes.

Have it shipped to you. A non-running car is always cheap, so, that plus freight could be the ticket.

What about all the bits in the cylinder?

Depends on how much is steel and how much is aluminum, as well as how much actually made it though the holes in the prechamber into the cylinders. The iron could (mostly) be fished out with a neodymium magnet on a flexible wire through the intake valve. The aluminum is a bit trickier to remove, but unless it is a massive amount, it will burn up or be blown out the exhaust valve pretty quickly once the engine is started.

I do not know much about the 606 engine ( familiar with 617 and 603 ) but injectors always spray fuel onto the GP ( when hot ) to fire the engine. I really doubt drilling the GP out would hit the injector. It is on top on the GP and not behind it. In addition, it is very hard to drill thru an injector. The fuel inside is miniuscule in any event. It is very likely coolant if the cylinder was indeed poked thru. The pre-chamber may also be in the way. In short, I do not know what happened but the head probably is toasted.

Sorry, that is factually incorrect as BC used to say. A good injector sprays onto the ball pin in the pre chamber, never onto the glow plug. A bad injector with a bad spray pattern can spray onto the glow plug and erode it till bits of it falls off causing extensive damage.

I am wasting my time to reply but I do it anyway for 2 reasons. BC is history. Secondly, I am saying the injector is above the GP relatively, whether it is DIRECTLY above is not relevant in the context of 'drilling thru' scenario.

Well thanks to all for the input. You guys that understand the anatomy of the 606 head all nailed it. It is indeed coolant I drilled into. I feel like an idiot thinking it was fuel. But I guess the odor of fuel was already so strong (I had to remove a few fuel lines to gain better access when drilling) that I just convinced myself I was looking at diesel fuel.

I still like renaissanceman's suggestion of trying to plug the hole with a set screw. I think what I will try and do is list it for sale as a part's/project car. If someone comes along that wants to attempt this I will sell it and be done with it. In the meantime while waiting for a buyer I will tinker with it when I have spare time on weekends in the coming months, trying out his suggestion.

Sorry about your misfortune, those OM606 glow plugs certainly have a (well-earned) bad reputation.

Last time I did mine in 2012 I put on a generous amount of Lubro Moly anti-seize, but every time I see these threads it makes me want to go out and perpetually hit them with PB Blaster every weekend until the day comes I need to do them again.:o

This prechamber diagram is from a 190D and may resemble your 606 prechamber. Per Kartek, you would have had to drill through the glow plug then through the opposite side of the pre chamber into the aluminum head casting for coolant to leak into the pre chamber. In that case, the set screw is not going to help....it will hydro lock.

Can you measure how deep you actually drilled? It would be useful information for others attempting the same job in the future. You shouldn't have drilled more than 1/2" before tapping ( where most of the meat on the glow plug was). The glow plug gets smaller in diameter the further in you go. What were you thinking?
http://www.kenrockwell.com/190d/images/lvp.gif

Two cases I see:

1.) he drilled all the way through the GP, opposite side of the prechamber and through the AL wall of the head into the coolant jacket. A set screw would not cause hydrolock -- it would plug the hole on the opposite side of the prechamber.

2.) The drilled hole was off axis enough to start cutting into the head before reaching the tip of the GP, and cut into the water jacket. If this is the case, there should be little or no coolant in the prechamber or cylinder. This may be able to be patched up too. I'm hoping Mike will post photos from the borescope so we can see/help.

Probably that he was tired and frustrated and thought hewas doing what he should do. Don't beat him up more than he already is doing to himself.

Scenario #2 above may be a real possibility.

I wish someone here could produce the same type of cross sectional diagram of the 606. I am sure it is similar to above. I have searched and searched but can find one. I would like to see exactly what the anatomy is. As you all know, the GP's in the 606 are significantly longer than other engines.

Yes, wasn't thinking correctly, nor did I plan proper. I should have held drill bit next to an intact GP and taped the bit at which point to stop.

Tired and Beyond Frustrated is more like it.

The best option for repair is installing a used head, or a complete running engine.

Mike: Out of morbid curiosity, how did you get to the point that you broke the glow plug off?

For next time (or next person attempting OM606 glow plug R&R):

http://www.peachparts.com/shopforum/diesel-discussion/376521-om606-glow-plug-removal-tips-tricks.html

That picture is of a OM602 or 603 single overhead cam. The 602/603 have the intake and exhaust valves on the right side and the pre chamber and glow plug on the left. The injectors are on the left so they can spray into the pre chamber. They are in different locations based on the head casting (different between a #14 and a #22). If you look at the inside of the head (top of the combustion chamber) on a 602 or 603 it will not be symmetrical. The 602/603 glow plugs are short and stubby - the total length of the element plus threads is on the order of a couple inches - since the pre chamber is pretty close to the left side of the head. This is similar to the legacy 616/617 engines btw.

On the 606 the dual overhead cams and 4 valves per cylinder make the top of the combustion chamber symmetrical. The pre chamber is dead center and the injectors point straight down with respect to the centerline of the piston. The glow plug now has to reach past the valve train on the left side to get into the pre chamber that is now dead center over the piston. This means the glow plug is now on the order of 6 inches long and the bore walls have coolant and oil passages on the other side.

This explains why the 606 GPs are prone to get stuck - you have about a 4 inch shaft past the threads in order for the GP to be long enough to extend into the centered pre chamber. Carbon builds up between the shaft and the bore walls, and it cools and hardens because of the relatively cool environment especially since there is oil and coolant on the other side.

The OM642 is worse - the GPs on that engine are nearly a foot long...same reason. No pre chamber on a CDI but it still has to get the business end where the action is.

http://i197.photobucket.com/albums/a...DI-cutaway.jpg

best I can understand, you drilled off center, and went into an adjacent water jacket, and it's running out the hole you drilled in the glow hole...

I wish I could find an image of an actual 606 head cutaway... but I can't this claims to be, but obviously it's not.

I spent a bunch of time yesterday looking for a cutaway....no joy. Lots of 617 images but no 606s.

If it turns out that the OPs head is trash, it would be fun to put it on a band saw and see what's actually going on. Might save someone else a problem.