So I screwed up and stripped the threadsfor the plugon my lower oil pan (SL500 MY98) and I'm now trying to figure out what options I have. I know that I could replace the oil pan but seeing that this would be a bit of a project, I'm looking for easier options first. I want to keep everything looking and functioning as stock so sealing the oil plug permanently and draining oil from thedipsticktube is not an option.
What I wonder now is if anyone have experience from mounting thread inserts in the oil pan, something like "Time Sert" inserts or similar? I'm kind of worried that there's not enough material to drill and fasten it properly in seeing that the oil pan itself is quite thin sheet metal? Do I have to worry about getting drill shavings into the oil pan when drilling out the hole or is this easy to get out afterwards?
Yes. It is thread restorer. It is an epoxy type product. I’ve used it in the proper application with great success. However, the problem it would have here is the surface must be completely oil free or it will flake off. Getting the oil drain so clean that there would be no oil migration during the curing time would not be easy.
I would recommend the slightly oversized self tapping plug and doing changes from the dipstick tube. I do mine that way and could do an oil change in a tuxedo -- since the oil filter is on top anyway - it is so much, cleaner, easier and safer (for me and the car). Hooked to my air compressor, my extractor gets all 8 qts out and I never have to worry about cross-threading or over- or under-tightening my drain plug. I do enough other underneath maintenance to give the underside a regular once-over.
Thanks for your input, very helpful! I will for sure start changing the oil through the dipstick tube but for now I just want to correct my wrongdoings
Does anyone know what size the original oil drain plug is? I've seen both M14x1.5 and M12x1.5 and I have no way of checking on my car right now. It has the M119 engine!
Some years ago I used to help with fixing Mercedes club members cars with a retired Master mechanic.
he taught me a few things such as the wonderful applications of pry bars and the limited applications of torque wrenches. Many times we amateurs want to torque the most ridiculous things simply because the factory has a setting.
I remember somebody on a list asking the torque setting for the bolts holding the distributor rotor. Sheesh.
he said the only real reason for torque wrenches is transmission parts, internal engine parts and one or two other things.
I remember when I put the aluminum Oiler tubes on the M119 I made darn sure with a beam type torque ranch that I only gave it the prescribed 10 N meters. You were torquing the bearings back onto the camshaft so I can imagine making that too tight what it would do.
ever since years ago I stripped a thread putting a bolt in for a valve cover I’ve had a healthy respect for overtorquing things.
spark plugs? A good mechanic knows by feel how much to tighten the plug. Not me, I’m not that confident so I will use a beam torque wrench and not a click type to get it to those 20 N meters to 30 Newton meters setting
If a click type isn’t calibrated right you can royally screw up your spark plug hole. And I always use a flexible tube holder to hand start the spark plugs and avoid any chance of cross threading.
as far as the oil plug drain, for years I’ve used a Topsider for my Mercedes to just suck the oil out.
when I have drained it from the bottom I just use a Short handled 3/8” Dr. and just get it snug.
I’m thinking about this now but my master mechanic mentor was this old British Limey and he had three standards for hand tightening fasteners.
They were, tight, tight and a half, once more with feeling.
I can’t see who suggested it from this editing screen but whoever directed you to the other thread — I thought the Loctite idea sounded good.
To repair the thread properly with Helicoil or epoxy thread restorer (yuck, I don’t recommend the latter), you would have to remove the oil pan anyway. Easiest and most permanent option would be to replace oil pan with new gasket. 30 mins work, since you’ve already drained the oil anyway.
Thanks for your input! Are you sure though that this is a 30 min job? I've read that you'd have to loosen the engine mounts and lift the engine to access all of the oil pan screws?
Although I really appreciate your input around this "google" thing (that seems great! ), I'm having a hard time finding answers to my original question around material thickness around the oil plug in the oil pan. I'd like to know if there's enough material to get an insert to fit properly.
If you want to get to original as possible not replacing the oil pan.
Get a reducing bung / bung fitting that would receive the same size original oil plug{purchase and used a new oils plug and seal].
The attached photo is what a general /typical threaded reducing bung / bung fitting looks like. They are also available as a weld on unit. You would need to get the correct size.
Then attach the reducing bung to the oil pan, your choice, welding on or drill and tap unit.
Just an idea i have seen a rubber insert that you push in the hole it as a bolt that goes through the center of the rubber bung then all you do is tighten it up they come in all sizes and are made of a fubber that wont rot when used in oil
Please go to google search page look up to the right hand side and click on images /
Then in image search box put this - Stripped Oil Sump Plug Repair
Hope this gives you some idea .
Hi Anton, I think you should replaced the oil pan. New ones cost around $50 - $150 from Ebay. I done it before..fairly easy on the old car. Good luck!
Jim
Permanently seal the plug and use a vacuum canister to suck the oil from the dip tube orifice. Less mess, no need to crawl under the car any more. That's what I do now.
Did the same thing to my M119-the plug ended up stuck inside the hole and stripped at same time, a couple of months ago....WWAAAAAAAYYYY BETTER to just get a new pan, plug and gasket! The plug hole is reinforced inside with a welded square nut...not difficult at all, you loosen the lower bolts of the motor mounts and raise the engine as if replacing the mounts; to give you better access to the front pan bolts.....get a miniature BIT ratchet AND get 5mm hex bit attached and remove the front bolts; the other ones come out easily....and switch out pans.....i looked at it this way—i took the opportunity to be able to put on a new oil pan gasket (it was slightly leaking anyway) and oil level sender....took me all but a couple of hours to do and I took my sweet time....as to the size of the plug...it is the smaller of the two....Good Luck!!
Super simple to replace the bottom portion of the pan. You can do it in less than an hour with a new pan, gasket and oil plug/washer. You have the added benefit of being able to check/clean the oil pump screen.
if all else fails,,,,,you can remove the oil pan. Take it to a precision welding shop and have a new nut, or actual factory part rewelded onto it. Or you can even weld on another brand of car, or tractor,,or whatever you may have. The point being, to weld it well, and maybe with a broad washer added to the inside. Match this all with the proper bolt, or a real drain plug. You can work wonders if you can find a quality welder or machinist, and arent too excited about remaining original......regards to all
The only real good reliable solution seems to seal it.
Are you sur anyway that changing oil if not recommended by extraction / succion on your car ?
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