Stuck Oil drain plug
 

Used a 6 point socket on it that fit exactly, long ratchet, and then all the points rounded off.
Bought the car recently, and this was going to be the first oil change by me.
I don't know if the previous owner got it in cross threaded or it is just stuck but it really is.
Any good ideas on how to remove it.
Car is a 1990 190E 2.6

First buy a new plug
Then use a pair of Vice Grips and tap them with a hammer.

If the bolt was in good shape I don't see how a 6-point socket would round it off. I would try vice grips next. Failing that, I would get a new oilpan if its easy to replace on that model.

There are several threads on this subject so a search would really help you with lots of ideas. However, I had (nearly) that exact experience recently. Only difference is I felt I was nearing the point of rounding the bolt so thought I should go to plan B before I ended up in that situation. As far as why it is so tight, I can give you a possibility. On mine, it had never been removed in 7 years and 140K miles. The dealer had always used a topsider. So the copper washer had gotten kind of stuck to the plug (my opinion). I had a good 6 point socket on it and was using A LOT of force and it seemed as if it was welded on. One issue is that I had "warmed" up the car (more like hot) and so I suspect this made the situation worse. What I did then is I sprayed the bolt head with "freeze-it" spray until it was cold on the theory that this would shrink it a little (I am a dreamer).. Anyway, it worked and I was able to break it free with no damage.

But you have a rounded off bolt head. Again, I would really suggest searching, but one of the ideas I remember is these special sockets Sears sells for just such an occasion. And also try when the engine is cold. And when you put the new one on, a little never-seize won't hurt!

Mike

Where can we get this stuff?
 

Is this the 'freeze it' spray you are referring to? http://www.trianglebiomedical.com/products/SHURFreeze.html
Wow, never heard of it before! Would this, among other things, cool a beer down in a flash? Seriously, I'm interested in buying something like this, for the same use you describe.

Had the same problem and vise locks, pipe wrench and hammered on sae socket wouldn't do it. Finally went to muffler shop with a 2" 3/8" bolt and had it welded to the plug at a 90 degree angle. when cooled I had the "handle" to break it loose. Cost - $10.00.
Tim

Yes, the "weld something to it" idea was another good solution mentioned in previous threads, but really the best I think was the special sockets from Sears. Everyone seemed to like them. As for the Freeze-it it is used a lot in electronics and I think you can get it at Radio Shack for about 7.99. They call it Envi-Ro-Tech freezer. Good to have around if you like wierd stuff. Who knows, it might work for you too! Anything is possible!!

Mike

i really
 

dont think these should round out if using the correct wrench. i bet you didnt have the hole cleaned out and the socket inserted all the way. i would think you would about break the wrench before rounding it out, if inserted correctly.

tom w

Hi, I had the same problem when I first bought my Merc.

I recommend you get Bolt-Out form Craftsman (Sears). It worked great for me. Rememeber to buy new drain plug and copper washer before you do this.

If your plug thread is damaged then you may be able to re-thread with bigger size and use bigger plug or worst case need new oil pan.

Good Luck

Link for Bolt-Out

You might want to try a "Snap-On" socket... the design of snap-on sockets/wrenches > is that they turn the nut/bolt at the flats and not the corners... ergo > no "rounding off" the stuck nut/bolt.

There are other tool vendors that use the same design..

pipe wrench?

Several direct blows to the drain plug with a 2lb hammer will aide at breaking the static tension between the plug, the copper washer and the pan. Once you have introduced the hammer to this dreaded rounded off beast, the vise-grips will be the weapon of choice to finish loosening this monster! If you are unable to extract the monster than I believe fusing another bolt to it would be the final round before one would concede to extreme options.

For the future: Prior to placing a wrench on the drain plug try hitting it several times with a good size hammer (brass whenevr possible), it helps. It does not matter whether the drain plug is an internal (allen type) or an external (bolt head type) you will avoid overstraining yourself and then leading to an injury. Nothing better than flat backing on the drive-way, or in the garage, your hands and arms in tight quarters and then peeling off some skin from the knuckles because the wrench slipped! :eek: F#*@

I spent my university years working in an oil-change garage, and any time I'd encounter this problem a set of vise grips always did the trick. I found the ones with the oval "mouth" were better than the ones with the flat "mouth" because you could get more contact with the rounded plug.

Mercedes are designed to have engine oil "sucked" out the dipstick tube.

Why not look at this as your opportunity to begin doing that.

It's a lot easier and cleaner way to go.

I recently changed oils using the pump method through the dipstick hole. Of course I do not know hoe much more oil was left in the pan, how deep the cable went.

For my next oil change I will surely use the sump plug. It is a 13mm size and I could not undo it using a normal 13mm spanner. I then tried a big adjustable spanner but that was about to round the edges off so I stopped immediately. I then used a 13mm socket and a ratchet and that did it.

The washer is not copper but leather/felt material. For a 13mm bolt it surely put up a lot of resistance.

By the wey if I remember correctly the bolt was hexagonal but the socket was not - that is not a good idea since there is the possibility of the socket rounding off the edges. For such bolts you need a hexagonal socket that is a 100% fit.