OK, I just went to change the oil on my newly acquired W124 300D and found that the sump pan drain plug was in REAL REAL tight and seemed to have the consistency of butter, ie after a little pressure the bolt just rounded off.

So what next.....I don't really want to resort to taking it into a shop and getting a mechanic to drill it out.

Somebody has recommended Mole Grips (are they called this is the States?)...basically a wrench with a nice set of grips that you can lock into place. Once locked, giving it all the muscle you can to shift it!!!

Is this the best idea, or can somebody recommend another way to get this shifted.

Cheers

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Current Mercs
R129 1994 300-24SL
W124 320E Turbo Technics Twin Turbo 350bhp

Previous Mercs
W124 1986 Quad Cam AMG Hammer, 45,000 miles
W124 300E Turbo Technics Twin Turbo 320bhp
W124 E500

On my 190E 2.3 8 valve. On my car there really wasn't much room to try many other tools. I used a Dremel rotary tool with a cut-off wheel and very carefully removed most of the bolt head all the way down to the shoulder. This took the pressure off the threads and I could just spin it out by hand. The copper washer got nicked but not the sealing surface on the pan. Good luck!

Consider getting one of those "topsider" oil drain devices!

The drain plug/copper ring/oil pan materials have a great way of electrochemically bonding themselves into one cohesive unit..I guess heat is the catalyst!

Stripped drain plugs are far too common, and even my indie balked at pulling mine off and resorted to the topsider instead.

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

I encountered the same thing. First I tried Vise-Grips.....no good. I eventually found a set of bolt extractors: they look like normal sockets from the outside, and on the inside they look "twisted". They basically eat into the metal, allowing you to use either a socket driver or an adjustable wrench and a lot of torque.

It could be it hasn't been off in a long time. Assuming there is any "stub" left to grab I would expect a big pipe/monkey wrench would grab it pretty good. You might try it cold and then try it hot. Might work better one way or the other. Just be aware that you could (technically) damage the pan if it is on really really tight! With a big enough wrench something will give eventually... I will be interested to hear what finally works.

Mike

Is this the stamped steel pan at the bottom? If you can't get it out with vice grips, you might just want to take it off. That way you can work on it on the bench, with a cool glass of suds by your side. Run a series of standard drill bits on the bolt FROM THE INSIDE, so the cutting action of the drill bit tends to screw the bolt out rather than in.(grind the head off first if you're doing this). Even if you miss a little, you can retap to a slightly larger size, and be positive you left no metal chips inside

I had this problem with my 90 300D. The PO apparently took it to someone who buggered it hideously. I tried vise grips and a pipe wrench and had a couple of local guys in the neighborhood try it as well, with no success.

I took it to an indy shop and a pro ground down two flat sides and torched it, and spun it off with visegrips in about 5 minutes. The owner told me to pay him whatever I thought was ok, I asked if $10 was fair and he said "sure".

He tightened it finger tight and I took it home and changed the oil and replaced the plug. You want to get a new plug specifically for Mercedes: the fit-all plugs will only hold if screwed on too tight.

It is not likely that a drain plug would have rusted on, being as there is always oil on the engine side

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Semibodacious Transmogrifications a Specialty

1990 300D 2.5 Turbo sedan 171K (Rudolf)
1985 300D Turbo TD Wagon 219K (Remuda)

"Time flies like and arrow, yet fruit flies like a banana"
---Marx (Groucho)

TopSider no, but MightyVac yes

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David
1986 300E Anthracite + ECodes + MB Mileage Award

MightyVac no, but Mityvac yes :p

Eric

A good ole boy at a welding shop removed a rounded bolt by placing a common nut large enough to go over the damaged head and with 2-3 hits with the MIG, the bolt had a new head and a clean socket removed it easily. Cost - $10.00.

Tim

I like it! Pull the same trick with JB Weld and maybe they will print the testimonial on the package next to the story of the housewife who fixed her garbage disposal. (When I aquired my FIAT 128 I could never understand why the oil drain plug seemed a little odd looking. I finally realized that someone had glued a nut onto the plug with JB Weld. The original required a big allen wrench that they apparently didn't have)

Mike

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

Last time I had to remove a rounded oil drain plug bolt, I followed Gilly's advice and used a sharp chisel.

I carefully created a good dent in the direction of removal and just continued to whack. Within a several minutes it started turning.

Haasman

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'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)

This sort of thing demonstrates why I am afraid to let others (particularly in low-skill areas, like tires/oil change places) work on my car (even my "other" car). There is a torque spec for this, but I've seen oil change places tighten the *** out of this with nary a thought. I know a woman who got a new oil pan installed at a BMW shop because of overtightening at an oil change place (at the oil change place's expense). Same goes for wheels. I usually bring wheels in to a place I can trust not to scratch/bang up my rims, they mount the tire - I mount the wheel. I went to one place I liked in the city I used to live in where air tools were not permitted in the tire area (no air hose connections). Reason: They had to buy $hundreds of 1980's dollar rotors on a newish Jaguar whose lugs had been overtightened to the point of distorting the rotors.

One of my spare wheels has damage in the lug area because someone in the past snapped off a lug, which had to be drilled out. Bet it was "torqued" with an air tool!

Spent a couple of hours over the weekend trying to shift the sump plug which had rounded off.

Tried using molegrips, but could I shift that plug?.....the bloody thing would'nt move

Anyway I did'nt want to end up doing any damage so I left it and drained the oil using a top-sider.

Thanks to everybody for the helpful tips........this bolt is going to have to wait for another day!

__________________
Current Mercs
R129 1994 300-24SL
W124 320E Turbo Technics Twin Turbo 350bhp

Previous Mercs
W124 1986 Quad Cam AMG Hammer, 45,000 miles
W124 300E Turbo Technics Twin Turbo 320bhp
W124 E500

get a cheap socket that is a little too small for the bolt head (you can use a metric or std. socket), put on some safety glasses, and hammer it on. Then use a ratchet or breaker bar to turn it. This worked like a charm for me in the past. Use a cheap socket as you probably won't be able to separate it from the damaged bolt.

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2005 Mercedes C230k sport sedan, 6 speed
1987 Porsche 924S - 968-engined track car