Any Machinists Or Diesel Techs Here?

[Totem]

This is not a toy home question but a glow plug one. I recently had hired a mechanic at a dealership (MB) to replace glow plugs in an OM606 w210 benz. These things are notorious for seized plug. He got 5/6 out and broke off the 6th. They called me and told me it would be an extra day... that turned into a week.. no calls nothing. I called them and find out the mech is in the "ER" with metal in his eye ; that he broke off a tap into the 6th plug and well "Sorry".

Sorry? they destroyed a $8000 motor and i get a "sorry".

Well heres my topic, where should i start on this tap. Its color in the picture is that of hardened steel so thats what i am assuming the tap is. the way I see it i can try the following:

1.) weld a nut to the plug and try to break it loose/back it out that way

2.) dremmel out the tap and try to tap again time consuming and will eat like 20 diamond burred bits and or maybe some carbide lefty bits

3.) try to find a machine shop (the first 2 i called laughed and said no thanks after hearing there was a Tap in there) and remove head send it out

4.) live with it and drive it as is (current solution)

Any other ideas or tricks?

[Maineah]

You will never drill a tap no matter how hard you try. I assume the head is still on the engine? I have tried heating them to take the temper out of the tap with limited success if there is enough sticking out yes a nut welded to the tap will generally work

[WME]

Buy a rebuilt head, drive what you got, remove head and find a machine shop that has EDM capabilities. Your choice!

[jdfrost64]

weld a nut on it

[Totem]

EDM, I am told , it $700 per hour. If that's true no thanks, also the immersion tank needed to house an OM606 head would be huge..

My brother in law is a Tool and Die guy for chicago stamping, he says i should give it one more extractor try and if not the old weld a washer then a nut trick.

Hes been with Ford for 25 years so I will probably listen to him unless anyone knows a shop with reasonable EDM. To be honest i hear lots of people discuss EDM but I have never met anyone that had it done for anything in actuality; that reinforces my belief that EDM is rare and expensive.

I had another guy tell me to make up a batch of Alum and a dam and let it eat the Tap/plug but am I unsure of how Alum would react with aluminum block.

[zero]

This is not a toy home question but a glow plug one. I recently had hired a mechanic at a dealership (MB) to replace glow plugs in an OM606 w210 benz. These things are notorious for seized plug. He got 5/6 out and broke off the 6th. They called me and told me it would be an extra day... that turned into a week.. no calls nothing. I called them and find out the mech is in the "ER" with metal in his eye ; that he broke off a tap into the 6th plug and well "Sorry".

Sorry? they destroyed a $8000 motor and i get a "sorry".

Well heres my topic, where should i start on this tap. Its color in the picture is that of hardened steel so thats what i am assuming the tap is. the way I see it i can try the following:

1.) weld a nut to the plug and try to break it loose/back it out that way

2.) dremmel out the tap and try to tap again time consuming and will eat like 20 diamond burred bits and or maybe some carbide lefty bits

3.) try to find a machine shop (the first 2 i called laughed and said no thanks after hearing there was a Tap in there) and remove head send it out

4.) live with it and drive it as is (current solution)

Any other ideas or tricks?

How do you drive with it as is? Isn't there a lot of compression leaking out that glow-plug hole or is it still plugged with a remnant of the old glow-plug?

I've had to remove many broken glow-plugs and taps from heads. Each situation varies. I'd start with a tap-removal tool made for what I assume, is a M6 X 1 mm tap stuck in there. Once out, then you'd have to drill out what is left of the glow-plug. I've had to pull the head on a few to avoid damage but can't say I've had to do it on a Mercedes. GM and Isuzu indirect-injected diesels, yes. In regard to the glow-plugs being stuck - are they swelling up at tips? That was a common problem with all direct-injected diesels until new-tech self-regulating (dual-coil) glow-plugs came out 15-20 years ago. Bosch sells the new-tech plugs as Duratherm. Beru of German also sells their own version. I'd never use anything else and NEVER anything from Delphi.

[zero]

This is the sort of broken-tap extractor I'd use for my first attempt to remove. Your glow-plugs are a standard M12 X 1.25 mm so if someone was trying to drill it out and tap for removal - it's likely you've got a M6 X 1 mm tap stuck in there. Takes the same extractor as a 1/4" SAE tap.

[Totem]

Karin, again, no i don't want to remove the head ($$$$) and there is no MDM shop near me and even if I did it would be cheaper to buy a reman head than to ship my messed up one to where a $700/hour MDM guy is.

anyhow well I picked up the car yesterday and what he called a "tap" was really in effect a hex extractor. he let me keep the broken extractor as a souvenir of his horrible service. I got to meet the moron mechanic whom would not even shake my hand and only complained how the dealership would not get him tools or training.

I asked him if he reamed the 5 plugs he was able to replace after seeing his work shop area and what he called "tools". He had no Klann tools at all, no Laser brand tools nothing, just rusty crap. This is NOT what i expect of a Licensed Mercedes Benz dealership. He did NOT ream the plug ports, and didn't even put anti-seize on the Bosch duraterm plugs that he did intstall effectively ensuring that I will have the problem again. Why did i even pay this moron? at least the elbow grease of the 5 he did do is done. too bad i will be removing them to ream, put on anti seize and put back in. The guy did one better too... he took the 6th glow plug and tie wrapped it to the intake header and put a ground wire on the motor to "fake" the computer into thinking all is well and not throw a CEL. so i have a red hot glow plug in my engine bay, yikes. I just cant even make this story up, worst tech ever. If in my mind i think about it, if i have a stuck plug thats threads are seized why on earth would i use a pound-in extractor which pushes more pressure outward into the threads of the block. What an idiot.

yes the car runs, crappily and knocks as one cylinder has no glow plug gets fuel washed until it warms up, yes the glow plug is still threaded in there.

The extractor is one of those hexagonal splined ones thats like super hardened that you hammer into a hole and then reef on...

JDE, I am thinking welding a nut is all I am left with if i want to do this the best cheapest way possible to back out that stuck plug.

I am not a fan of drilling it out and trying to helicoil. I do have average welding skills and i think that the heat could help too.. the only thing i cant get over is that extractor is pushing out... my brother says i need to get that extractor out and then weld

[snail powered]

The figure of $700.00 is not the hourly rate, that is the price given for the minimum job size that shop was willing to accept. That $700.00 quote was based on an 8 hour work day. A lot of production shops do not want to accept small jobs of an hour or so as it is not a profitable business model for them. So even if you only had 1 hour of work you would be charged for 8 hours. There are shops who will do small jobs and bill only for hours actually required but apparently the shop that quoted that price is not one of them.

I checked with my partner who sources out production parts for his business. The hourly rates for MDM are in the range of $75.00 to $100.00 an hour plus or minus depending on the shop, the location and if you are a regular customer. But be aware there may also be a setup fee associated with any machine shop work and that fee is not normally included in actual machine time quotes. But they will let you know that there will be an extra fee involved.

[zero]

I'm amazed that an alleged reputable repair shop has the balls to screw up a job and then - not make it right. I worked at a lot of repair shops and dealerships and can't think of one that would try to get away with something like that. Not unless someone brought in a near impossible repair job and signed a waiver assigning NO responsibility to the people trying to fix it.

As far as this broken "easy-out" goes - much depends on it's size - and if it's the tapered four-sided type, or a left-hand-threaded-spiral type. The tapered four-sided type will pull straight out if you can weld something on to the end to pull on. The spiral type will not.

One of my trucks with a V8 indirect-injected diesel has had one bad and seized glow plug in it for over 100,000 miles. Never been a problem. An 8 cylinder with 7 good plugs starts fine. Just smokes a little at start-up with the one non-heating plug. No effect on actual running. I suspect you can do just fine with 5 out of 6 working if you can't get that thing out. I can't see where it's worth yanking the head to access that precombustion-chamber area to fix. That missing glow plug has no effect on normal running. Just cold starting and first-run emissions.

You say you had Duratherms put in. What was in their before? I suspect single-coil plugs that got swollen tips?

The little podunk rural one-man repair shop down the road from me charges $55 per hour. Last year he did an oil-change for a guy with a Subaru Impreza and put on the wrong part # oil-filter. The guys engine seized a few miles after leaving the shop. The repair guy and shop owner got him an entire replacement engine and installed it, besides getting the guy a loaner car. That shop you went to ought to be fixing your rig for free, at the least.

[zero]

One caveat to running with one non-working glow-plug. I don't know what you have for an automatic glow-plug controller. Most modern ones work by sensing engine temp, voltage at the plug, and amp-draw. When one glow-plug is not working . . . with some controllers -they will not run as long as usual during a cold-start preheat cycle. Usually no big deal unless you have to start in some very cold temps. If that IS an issue - it's easy to add a controller over-ride button so you can force the plugs to run longer when needed. No danger of using a manual control with self-limiting plugs like the Bosch Duratherms you got.

When my GM V8 diesel had 8 good-working OEM plugs - it cycled for 14 seconds in a very cold prestart. When GM gave up on their own crappy Delco glow plugs and switched over to German Beru plugs as replacements (still in Delco boxes) - the cycle time went to 10 seconds which was not always enough. I added an override. Later when one plug got the terminal broken off and only 7 were working - the controller wanted to cycle at only 8 seconds.

No worry about diesel fuel "washing" your cylinderwalls during cold starts in that one cylinder with no glow-plug. Unlike gasoline - the diesel oil gives plenty of lube - even the modern ultralow-sulfur garbage since it gets lube additives put in after the sulfur removal process. There are many mechanical injection pumps around with over 1,000,000 miles on them and the only lube those metal parts ever had was diesel fuel.

Just be glad you have a system with the glow-plugs wired in parallel Some have them wired in series and with them - when one plug fails NONE will work.

[Totem]

The shop calls this an "existing condition" the stuck plugs that is. They warned me verbally that they would attempt to extract but that if it broke it was on me and asked me if I accepted that risk. Had they just busted it I would be in court. In the end I learned a valuable lesson here...to do my own work. I ever increasingly trust shops less and do stuff more myself and in trying to avoid this very problem I ended up causing it. The person to blame is me. I can guarantee you if I ever have a situation like this next time I will go "interview" the mechanic and inspect his tools BEFORE getting work done. It may seem weird but had I just made sure the doofus had Klaan plug extractor toolkit like most reputable dealership mechs do I'd be fine instead of assuming they weren't employing homeless mechanics like this shop.

To "make it right" he wired the extra glow plug and tie wrapped it to the header under neath so it wouldn't touch anything. So no CEL and the plug glows red hot you can see it in there .... that's scarey to me but the mech said it was fine. The car sounds like absolute crap for about 4 minutes and billows smoke but starts and runs fine after she warms up.

I was advised to "live with it"... Problem is, will it start in Feb in Michigan at 8:00 AM after being out all night not plugged in? this is my wifes car...

[zero]

The shop calls this an "existing condition" the stuck plugs that is. They warned me verbally that they would attempt to extract but that if it broke it was on me and asked me if I accepted that risk. Had they just busted it I would be in court. In the end I learned a valuable lesson here...to do my own work. I ever increasingly trust shops less and do stuff more myself and in trying to avoid this very problem I ended up causing it. The person to blame is me. I can guarantee you if I ever have a situation like this next time I will go "interview" the mechanic and inspect his tools BEFORE getting work done. It may seem weird but had I just made sure the doofus had Klaan plug extractor toolkit like most reputable dealership mechs do I'd be fine instead of assuming they weren't employing homeless mechanics like this shop.

To "make it right" he wired the extra glow plug and tie wrapped it to the header under neath so it wouldn't touch anything. So no CEL and the plug glows red hot you can see it in there .... that's scarey to me but the mech said it was fine. The car sounds like absolute crap for about 4 minutes and billows smoke but starts and runs fine after she warms up.

I was advised to "live with it"... Problem is, will it start in Feb in Michigan at 8:00 AM after being out all night not plugged in? this is my wifes car...

One missing glow-plug in itself won't have much of an effect on cold starting. The possible indirect problem is if your "glow-time" is now a lot shorter at pre-start. All depends on the automatic controller and how it operates. I don't know how your car was when it normally cycled with all the plugs working. If, let's say it would come on for 14 seconds before when 30-40 degrees F outside, and now only comes on for 8-10 seconds - it will start harder and skip and smoke on ALL the cylinders until it runs a bit. Installing an over-ride button is one work-around. Plugging in the block-heater is another. Or - just using it as it is and let it smoke a little won't hurt anything either as long as it starts OK. The GM and Ford IDI V8 diesels will lose around 2 seconds from the cold cycle time with one plug not working. My Isuzu however - that only has 4 cylinders - will drop from a 12 second cycle time to around 4 seconds with just one plug not working and that makes it miserable to start.

[Maineah]

As long as the resistance is there even with the glow plug not in the head the cycle time should be the same how ever you a taking one cylinder along for the ride and it ain't going to be happy about lighting so smoke and rough running on start up is going to be some thing you'll have to live with. Most US built V8 diesels I have dealt with 1 plug not working rough cold idle 2 plugs not working hard start 3 not working may not start.

[zero]

Many modern controllers (since early 90s) sense the change the glow-plugs go through as they heat. Resistance and amp-draw changes as they heat up. A broken glow-plug won't do that. Subsequently different IDI diesels do different things when not all the plugs are working. All depends on the type of controller. For Totem - what ever effect this has had, or has not - I suppose is already been observed.

With the GMs that had electronic and not thermal controllers (1986 and up) - just changing 8 working original Delco plugs (Delco AC11G) over to 8 new German-Beru plugs (boxed as Delco AC60G) resulted in an engine that would not start properly. Not until the controller got "tweaked" a bit to work with the different resistance-cycles of the newer dual-coil plugs. Ford diesels (International Harvester) of the same time also switched over to German-Berus boxed as "Motorcraft" but with them - no mods to the controllers were needed.

Yeah, I know . . this has nothing to do with Mercedes or Toyota.

[WME]

My old VW Rabbit diesel would get hard to start when really cold. I just glowed it twice and the extra heat made the difference.
My 58 MBZ 180 D had 5 glow plugs 4 in the engine and 1 in the dash, no auto glow. You just twisted the start lever to the glow position and waited until the plug in the dash was nice and red, then twist the lever further and cranked the engine.

[zero]

My old VW Rabbit diesel would get hard to start when really cold. I just glowed it twice and the extra heat made the difference.

My 58 MBZ 180 D had 5 glow plugs 4 in the engine and 1 in the dash, no auto glow. You just twisted the start lever to the glow position and waited until the plug in the dash was nice and red, then twist the lever further and cranked the engine.

I've got two industrial tractors and one farm tractor that had that god-awful Mercedes 180D glow-plug setup. Bosch came out with an upgrade kit that greatly improves it. The original system that you are referring to used glow-plugs that operated at less then one volt each and all five were run in series. Four in the engine and one in the dash as a glow-indicator. If any one of those 5 burnt out - none would work. A very slow system but simple. Bosch came out with Duratherm dual-coil plugs to replace the originals. 12 volts and hooked in parallel instead of 1 volt hooked in series. Makes a HUGE difference in cold starting and reliability in 180D and 190D cars, Unimogs, and many industrial and farm tractors.

[WME]

Not the best design for sure, but the glow plugs went 275K until the engine broke the crankshaft. Got a long block from Frigiking. They used a bazillion of them to power trailer refer units.

P.S. The crank broke on the #3 bearing and I drove it home for 20 mi that way. Turned out that the crank was defective from the factory, it had a bubble the size of a nickel at the #3 bearing. MBZ said sorry no warranty!! Your OME pictures sure are familiar.

[Maineah]

The old MB were pre chamber heads and they needed a lot of heat. I think you'll find that they were covered by a single copper strap from glow plug to glow plug and the ground being the head. The dash glow plug was the resistance unit it served as ballast for the other glow plugs it alone was the series wired unit. Those old grow plugs did last a long time and were pretty trouble free that still did not make the old things easy to start though.

[zero]

The old MB were pre chamber heads and they needed a lot of heat. I think you'll find that they were covered by a single copper strap from glow plug to glow plug and the ground being the head. The dash glow plug was the resistance unit it served as ballast for the other glow plugs it alone was the series wired unit. Those old grow plugs did last a long time and were pretty trouble free that still did not make the old things easy to start though.

Nope.

Those old plugs were ALL in series that I know of and I've worked on quite a few 180Ds and 190Ds.. Not just the indicator. The heat-cycle and resistance of each glow plug was the same as for the resistance-indicator unit and all five were wired in series. I've never seen a Mercedes with those 1 volt glow-plugs wired with a common tie-bar on top. Not sure it would be possible unless a huge resistance was used. Those plugs will blow apart if voltage goes over 2 volts. Wiring in parallel is what is done when they are converted to the new fast-heat 12 volt Duratherm plugs. The original series low-voltage setup works just like those old cheap Christmas tree lights that would all go dead when just one bulb blew.

One photo is the 1 volt plugs and series connectors from a 190D. Another how it looks when converted. The other photo is the same 1 volt plugs as used in British International-Harvester diesels. Same setup. Both IDI diesels.

[WME]

I bought the car for $1600.00 drove it for almost 20 years and then sold it for $14,000. That was 18 years ago and some of the details have slipped by. But I do seem to remember a flat strap connecting the glow plugs. The 180 was a OHV pushrod engine, the 190 was an OHC engine

Didn't mean to start a food fight.

[zero]

The glow-plugs I showed used in 180D and 190D Mercedes were hooked in series. Many ties bars and not one common bar. I don't know what model car you had so cannot comment. No "food fight" here. Just facts. I've converted several from the old series system over to the new parallel system.

As far as the comments about using engine ground via the glow-plug base/mount for power on one side and a common tie-bar on the other? Can't happen with the plugs I showed. They are isolated/insulated plugs and not self-grounding. Plugs were made by Lodge, Lucas, Champion, etc. Champion CH28.

Same plugs were used in Mercedes 170D, 180D, 190D, and Unimog 411A. Also in many British and Indian International-Harvester tractors and UWD Thermoking engines. That is the total scope of what I'm referring to. All of those mentioned used the same series plugs with insulated dual connectors and the plugs were not self grounding. The two electrical connectors are marked A and B. Neither is grounded to the base.

If your car had a mechanical glow-indicator in the dash and NOT an electric indicator light - it had to be in series. If it had a light-bulb in the dash - then it could be in parallel with a common tie-bar. The theory-of-operation with a mechanical glow-indicator in the dash is having all 5 heaters hooked in series and all drawing the same power and heating at the same rate. This way, what you see on the dash is what is also happening with the glow-plugs in the engine.

[zero]

I bought the car for $1600.00 drove it for almost 20 years and then sold it for $14,000. That was 18 years ago and some of the details have slipped by. But I do seem to remember a flat strap connecting the glow plugs. The 180 was a OHV pushrod engine, the 190 was an OHC engine

Didn't mean to start a food fight.

I got looking around my books and the Net trying to find an older Mercedes with parallel plugs (common tie bar). Didn't find anything but DID find this video all about the series plugs used up to 1979 in Mercedes. Amazing what people take the time to post on U-Tube. What this guy is showing is what I've been talking about.

[WME]

The older design is series like you said. The give away is the insulating block on each of the glow plugs.

Another weirdness of the engine was the throttle butterfly, the designers couldn't get the engine to part throttle cruise smoothly so they modulated the fuel pump with intake vacuum. To help mine out the entire throttle linkage was converted to Heim joints or ball joints, nice to know jet engine mechanics. In reality, driving in So Cal, the car had two speeds WOT or idle. The cruise/top speed was 72 mph

[Maineah]

Yes I forgot about the old style glow plugs have not seen them in 25 year and they were old then. It not for nothing they were up graded can't say it made them any easier to start. Those old things would not make a good get away car unless you kept them running.

[zero]

The new plugs when installed in the old engines results in a much faster starting engine. Instead of holding the series-wired 1 volt glow plugs on for 30, 40, or more seconds - the parallel-wired 12 volt plugs heat in 8-10 seconds. Makes a night-and-day difference in ease of starting when cold.

[zero]

The older design is series like you said. The give away is the insulating block on each of the glow plugs.

Another weirdness of the engine was the throttle butterfly, the designers couldn't get the engine to part throttle cruise smoothly so they modulated the fuel pump with intake vacuum. To help mine out the entire throttle linkage was converted to Heim joints or ball joints, nice to know jet engine mechanics. In reality, driving in So Cal, the car had two speeds WOT or idle. The cruise/top speed was 72 mph

And yet another weirdness was the air-choke to turn the engine off instead of a fuel-delivery shut-off . Kind of like what Detroit Diesel used as an emergency shut-off on their 2 stroke diesels. I saw one very high mile Mercedes that would not shut off all the way anymore. Seems it would suck enough oil through the valve-guides to keep on chugging (also like a Detroit Diesel). No problem with a sticks shift. Just jam it in gear to make the engine stop.

[Maineah]

If a diesel has fuel, engine oil will do, it will run as if you had your foot to the floor and then some. After the fuel shut off cable went away MB used vacuum to operated the door locks and fuel shut off. The door locks would develop a vacuum leak and the engine would not shut off when you turned the key off then you would have to open the hood and manually shut the rack down, The plate in the intake was intended to stop a run away engine by cutting of the air flow to an engine oil fueled diesel often related to turbo failure.

[Totem]

Wife has been driving it a few days now and we've been keeping it in the garage to stay warmer which is a one car only... so far so good.

The motor is pissed when it first starts, pings and knocks for a few minutes then runs fine.

I plan on driving it this way until it won't anymore and then take a swipe at the plug with welder and nut approach. I may try that approach over xmas break too if I have time. i have located a machine shop that guaranteed they can get it out, but its 1.5 hours away; so that's the fail plan if I cannot get it out myself. The machine shop also will rebuilt the head and do valves, seals stems etc remove the stuck plug et al for $300 out the door. They have an import shop that will remove for repair at machine shop and re-install for $1500 next door. I am going to go that route worst case. I betcha though... that I get that sucker off with a weld. I'll post a picture when i revisit it this December. Many thanks to you all for your advice. I am of the thinking I won't hurt anything by driving as is till Dec.

[zero]

If it was mine, I'd leave it the heck alone as long at it's parked near an AC 120 volt outlet. One non-working glow-plug hurts nothing but cold starts and cold-start emissions. Plugging in the block-heater in real cold temps will fix all that.

My four-cylinder Isuzu diesel has had one dead plug for 5 years now. Yeah, I could change it - but too lazy.

Now if it was a vehicle or tractor that got parked away from grid-power and needed to get started in the cold - I'd have all those plugs fixed. I have a plow truck like that. Need a portable electric generator to run the block heater which is a pain-in-the-a**. Having all the glow plugs working makes things much easier.

[Totem]

thats the problem, she doesnt have 120AC plug at work and works 3rd shift... in Michigan...

[WME]

I see a welder in your near future.

[zero]

thats the problem, she doesnt have 120AC plug at work and works 3rd shift... in Michigan...

Bigger rigs are using on-board diesel-fired block-heaters now so AC power isn't needed to start cold engines. Obviously not something that's cost-effective for your car. If it was my car - I'd try it in the cold first before spending possibly thousands of bucks yanking the head off. 5 working plugs out of 6 should start that engine fine IF they still cycle long enough. If not, I'd add a push-button glow-plug controller override to make them work longer. That all being said, my first choice would be to remove that broken not-so-easy-out IF possible within reason. That could turn into a huge mess though. Even if you DO get it out - then what? You still have a stuck and broken glow-plug casing in your head. Is it cycling with less time now during a first cold start??

[Totem]

that's why I'm not trying to get out the easy out; I'm going to use it and weld right over top of it a nice nut. @WME, I already have a welder, just a cheapo wire welder, (no gas) flux core. I am like a surgeon with that thing though after 4 years of fixing crap. I have almost no fear of trying to weld a nut onto the stuck plug and letting it cool a bit, then hitting it with an impact turned on low. betcha that sucker backs right off or snaps. If snaps I just say screw it and drive on it like JDE said. SO far so good on what he said too it runs just fine with 5.

[WME]

Just glow it 2x on cold mornings.