A bonded seal / washer (basically an o-ring set inside an oversized washer) might be a longer term fix. Basically the o-ring gets squashed a bit when you tighten that flange bolt down and seals but the washer round the outside stops the o-ring extruding outwards.
or getting flattened.

 

Thanks Iwaj , good idea.
My plan B was going to be to use a 1mm thick copper washer as well.

So far Plan A is working well , so unless it starts leaking again I will leave well enough alone.

 

Copper washer will probably do it. Instant gasket won't last long though.

 

Iwaj ,
I think I have more faith in silastic gasket than you,,,
If it can seal a breather cover for 10 years it should manage a little bolt hole for quite a while.
Time will tell I guess.

 

I once used some "quick cure" black RTV on an oil pan for a Ford Windstar. It was up and running within an hour of tightening the last bolt, and it still holding to this day. RTV is pretty good stuff, and actually what MBZ uses to seat their oil pans and on their newer engines (M272/M273 and later) the valve covers.

 

^ Real name "Phil Swift".

I fucking HATE instant gasket goop. In my teens I knackered a motorcycle engine because I tried using some to plug a leaking base gasket and ended up blocking the feeds to the cylinder head.

 

Fair enough,,,I have seen cases of engine oil pick ups being blocked by loose pieces of rtv too.
I thought about it and as far as I could see, in this case there would be zero chance of rtv getting anywhere near the sump or oil galleries etc...
plus I only used a very small amount , just to fill the irregularities in the surface where the bolt contacts.

 

You guys do realize that the gasket for the oil pan on these cars (as it is most modern cars) is RTV, right? MBZ uses Loctite 5970.

 

Yes. Applied by robots (not stupid humans) in a factory environment.

(Cue Hovis commercial music)

I remember when we made our own gaskets out of phone book covers. Rich folk bought sheets of gasket paper or cork from auto parts stores, traced the outlines of the parts and cut their own. I shit you not...

 

Thanks Rodney , yes ,,,,
I have seen a great video series on youtube,, E55 Engine Rebuild,,,,which shows all the procedures. The guy is brilliant,,,he removed an engine from a car out on the street....amazing to me..Then bought another ,took it apart and re built it .
Anyway , he shows applying gasket maker to the upper oil pan,,,going to the inside of some bolt holes and to the outside of others,,,it made me wonder if the guy who built my engine made an error and went outside of the hole instead of inside , thereby allowing oil to work its way into the hole ...

 

Thanks Rodney , yes ,,,,
I have seen a great video series on youtube,, E55 Engine Rebuild,,,,which shows all the procedures. The guy is brilliant,,,he removed an engine from a car out on the street....amazing to me..Then bought another ,took it apart and re built it .
Anyway , he shows applying gasket maker to the block for the upper oil pan,,,going to the inside of some bolt holes and to the outside of others,,,it made me wonder if the guy who built my engine made an error and went outside of the hole instead of inside , thereby allowing oil to work its way into the hole ...

There is a prescribed bath for the sealant. On the lower pan, it's all inside the bolt holes. On the upper pan, it's inside the rear bolt holes, but outside the front 11 (it would be the front 12, except it's inside the last on on the left, inside the bend. The difference is whether the bolt hold is encase in the engine block or if it goes through the block, like it does on the rear hole that leaked on yours. So yes, it is possible that your rebuilder did it wrong.

 

Those are the same WIS docs I looked at. When we say "inside" vs. "outside" the bolt holes, we don't mean that the sealant is actually placed inside the bolt holes, but whether it is placed between the bolt hold and the outside edge of the pan, or between the bolt hole and the inside edge of the pan.

If you look at the first diagram, where the "F" arrow points, the holes to the left show the sealant path going to the outside of them, but the holes to the right show it going to the inside.

 

^^^ Yes, my sloppy comment there...

I was really referring to the second drawing - which I guess is the upper pan, and has all the sealing inside the line of bolts. The first drawing is the lower pan and that sealing certainly goes from inside to outside the line of bolts.

 

The first diagram is the "upper" oil pan, which is attached to the block. The second diagram is the "lower" pan.

 

Thanks Keyhole and Rodney for the diagrams and comments.
My engine is a 'handbuilt by one man ' AMG M113 988 which has never had repairs ,,,
After seeing the diagram it's hard to imagine the builder getting it wrong,,,but anything is possible I suppose , or maybe he didn't lay down a good bead of sealant at that spot ???

Anyhow , it doesn't really matter now , it's fixed .

Just out of interest , Rodney , you say that bolt goes through the block,,,so where does it come out ? ie where would the end of the bolt be ?
Inside the crankcase ? If so , maybe the oil leaked down from there ?

 

No, just into a "dead-end" hole drilled into the block during manufacture. And even though your AMG engine was "hand built" by "one man", it was actually built using the same tools (including robotic ones) as the assembly line built engines. It's just that one man does all the work and supervises it.

Thinking more about this leak, if you look back at Keyhole's diagram, the leak is coming through a bolt hole at the back of the upper pan, correct? If so, that would be "outside" of the sealant path, which means that there must be a leak in the sealant path there and it's just coming out around the most convenient spot, which is at that bolt. My guess is that you will continue to have a leak.

 

Yes , it was the rear right corner , a 30mm flange bolt ,,,so the oil is coming from the sump , between the upper oil pan and the block ,
and yes, it will continue to do that ,but now it will remain inside the bolt hole instead of dripping out ,,,I hope.
Thanks again for the extra info.

 

Rodney,
I'm feeling luck you are so helpful in this forum. I too have a leak at the rear right side bolts. Its very minor so I will tackle it later when I tackle the rear main seal.
My question is how do I print the pages from my WIS. Also, I am unable to open the pages of the work shop manual. I get the message at the bottom "error on page".

Any help is greatly appreciated.

Thanks in advance. Daryl

 

Hi Daryl,

There is a print button in WIS on the top right of every page - it's the usual "printer" icon. You can print to paper or used something like Cut PDF and save it.

 

I’m having s little bit a leak in that area too. I’m thinking it’s the rear main seal.

 

Rear main seal leaks can be 'monitored' for a long time ,,unless they get really bad ,,but often they don't ,,,I wrapped a piece of rag around the small pipe that runs along that area to help soak it up rather than having it drip down.