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M104 with a cracked oil pan

4K views 20 replies 10 participants last post by  topgun 
#1 ·
Yah, so I'm an idiot...hit a concrete parking thingy & cracked the oil pan...

I've got a '95 W124 wagon (F313953)...later model...with a M104.992. aluminum / potmetal amalgam pan. Sanitized with degreaser...then Acetone...cleaned mucho room around the 5 inch hairline (1/64th inch, perhaps 1/128th, inch maybe) crack...scuffed it up with sandpaper...did best could be done before laying down the JB Weld.

Question is...RTV or JB-Weld. RTV might be more flexible for temp fluctuations...concerned about rigidity of JB with up/down temps of aluminum/JB differential...thoughts...ideas...suggestions...experience?

Seems JB might be 'stronger' but more rigid (stiff)...properly cleaned (de-gunk'd...acetone'd...cleaned to the n'th anal degree) might be better with something more able to flex vs. breaking the bond with the metal under heat...

Hylomar?

Please...thoughts...??
 
#3 ·
I 2nd that statement. I had a old C4 Audi A6 wagon that also had a cracked oil pan. Did the JB Weld trick. It held (for a little while) but then blew out and almost grenaded the engine.

Pan replacement is the only fix IMO.
 
#5 ·
What a bunch of wimps! What fun would that be to just replace the pan. Boring. It's not even sporting, no challenge to it whatsoever. I say JB Weld or Devcon Liquid Steel. You've got to get the crack really clean, tilt the car to drain all the oil off the bottom of the pan, vacuum the crack, blow it with compressed air, spray it with brake cleaner with a plastic tube, do it all again, let dry, then two coats, first one with a stiff putty knife and a lot of pressure to push material into the crack, let dry for a day, then a second wider one, maybe even a third wider one. Then confirm that your oil level sensor works, and throw a gallon of oil in the trunk. Have some fun!
 
#8 ·
As Kestas mentioned above,
you will not be able to stop the oil from creeping out that crack to get the JB weld to hole, at least long term. Although, if you do, theoretically the JB weld will hold. It is some tough stuff. But, would you be comfortable knowing that if the JB weld does let go, let's say on a long trip, the affects could be pretty bad?
If it was me, I would just get a used pan, new gasket and change it. Time for an oil change any way, right?;)
 
#9 ·
Forums like this are notoriously free with spending other people's money. People have been successfully fixing cracks in alloy oil pans with JB Weld for decades. A hairline crack is a no brainer. It's likely to hold for many years and the life of the car, and if it doesn't, to be a small slow leak that is easily detected early. The option of replacing the pan is always there later. Replacing a 104 oil pan is no small job as there is just one pan, no lower pan.
 
#10 ·
For every repair task there's a right way and many wrong ways. If it were MY CE I obviously would be replacing the pan, whereas my car's PO would use scotch tape. LOL!! Just as I no longer play with a leaking radiator since they are only a hundred bucks and change, I wouldn't play with a cracked oil pan. How fun would it be driving down a lonely highway at night when you suddenly realize that all your oil is gone, and so is your engine? How many miles to walk? Yeah, let's glue it...
 
#11 ·
The premise that the oil is all going to leave suddenly and catrostrophically is a good argument or pretext for replacing the oil pan, for those inclined to do so. How that could happen to a hairline crack covered with epoxy is beyond me, other than another oil pan collision. But indeed it is a personal choice. If the car is typical I would probably part out such a car before replacing an upper oil pan. But more importantly the original poster has seemingly already made that choice - he didn't ask for our opinion on replacing the pan, only on what material to use to repair it.
 
#14 ·
What is "beyond me" is that even a weekend warrior mechanic, with even half an ounce of sense, would seriously recommend using epoxy as anything other than an emergency stop-gap procedure until they secure a used or new pan.

And what is further mind boggling is that you think the owner of an expensive engine should rely on a littler sensor in the oil pan, when using an epoxy patch. If somebody came in here and stated they were going to put on one tire that was a completely different size than the other three on a 4matic....would you go along with that and give him a good brand recommendation, just because he's made up his mind to do it? I see that some things around here never change...:rolleyes:.

Kevin
 
#15 ·
One of the things that has to change is to stop thinking of it as an expensive, valuable car or engine - it isn't. One has to adapt to the economic realities of the market value of your car. This car is likely worth more in parts, with or without an engine, than it is as a driver. It just doesn't make economic sense to replace an oil pan when a minor repair is likely to make it last until it otherwise dies of natural causes, which is not likely to be far off. But as previously said - it's a personal choice. Many people choose to consider economic rather than emotional issues in repairing their car, and it's their right.
 
#16 ·
I didn't say the car was expensive, I said the engine was. Find me some quotes of m103 box engines substantially less than $2,000. And a factory fresh engine in a crate would be many times that. Nobody competent in their right mind would rebuild that entire engine for less than two grand after a seized, no-oil scenario. You act as if we're talking about some cheap, Chevy 350 V-8.

Sure you can buy a junker engine and go to all the trouble to substitute with that...plenty of people love and brag endlessly about rolling that way. In that sense the cars are disposable as you always proclaim them to be. And if memory serves me, you're the one who advocates buying three of four of them and using them as donor cars to keep one running, if need be. As if everyone has that kinda space and resources.:rolleyes:

Kevin
 
#17 ·
Well gents,
you both have valid points. I guess, the OP should decide on which side he belongs and decide on his fix.
To some these are just old cars not worth more than $1-2k and to others, the market value does not affect their choices when repairs are needed. I belong to the latter because for me, my CE is a wonderful car.
Any way, we are here to help anyone who needs help and advice.

Bit off topic, I just saw a 94 E420 BLK/BLK no accidents, excellent paint and interior, new tires, brakes etc with a bad wiring harness for $1,000!!!!
I just don't get it. I mean, just get some wires and fix the darn thing!!!
Solder gun, solder, shrink wrap, a bit of time and the car is good to go!!!
Oh well.....
 
#18 ·
Exactly, to me the cars are more, especially since I'm the original owner and paid almost $65K for my car back in '93. They are rolling art and a magnificent example of how cars can be engineered, if bottom line isn't always the dictating factor.

I think the reasons these cars have plummeted so far in value recently are due to parts and repair costs. In addition, MB is not exactly a company that supports the notion of DIYers. Corporate MB always wanted you to go back to a dealer or a certified MB mechanic. It keeps it 'all in the family' that way and insures the mystery of the marque.

But since prices have plummeted so on 124's, strange bedfellows have embraced the cars (like teens having these as their first cars!). It's great for me quite honestly, because it forces most parts to be plentiful or at least not unobtainium.:thumbsup:

Kevin
 
#21 ·
My Car was bottoming due to worn shock and i punctured the oil pan twice in a space of one week, in both cases I opted for welding because I believe its all down to how professionally it is done. If done badly even something as simple as replacing the pan can be costly in the end.
 
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