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Oil pan leaking at filler casting - 1925 Nash


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I've got my oil pan off while doing work and I noticed that a previous owner smeared RTV around where the cast iron filler neck is riveted onto oil pan side and bottom in an obvious attempt to stop a leak... surprise, it's still leaking!


I do not see a gasket between the casting and stamped steel pan... I'd like to fix this but am wondering what to use? Solder, clean and JB weld? I don't really want to grind the rivets and remove the casting, but maybe that's the way to go to get everything clean first. 


Who's had a similar issue and what did you do? 



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I'd be inclined to use soft solder but you'll have a heck of a time getting it clean enough. I would never use JBW or any of the "quick-fix" instant gasket solutions. The best solution would be to grind the rivets off, clean everything completely, re-rivet it and then seal the joint with solder — which is probably how it was done to begin with.

Edited by JV Puleo (see edit history)
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If you do decide to re-solder, be sure to clean the surfaces to bright metal, including the areas that will be directly under the rivet heads .  Tin the surfaces to be joined before riveting.  You will find that the solder will flow into the joint with no flux trapped between the parts to cause rust. Don't forget to solder the rivet heads. Use only steel or brass rivets, no aluminum. Soldering is a skill as is riveting. Do your research before you jump in.

Good luck,  Terry

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When checking the engine on my 1925 Buick to find out why I was having low oil pressure.


This is where they had RTV blue on my oil feeder line joint.


 Before clean-up.


   I laid out a board to keep all in alignment so there would be no undue flexing during assembly to the bearings. 


Edited by dibarlaw
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7 hours ago, Lahti35 said:

Thanks for all the info guys, very interesting. 


I wire wheeled all the RTV off and it is indeed soldered. I'm going to try some soldering on some scrap steel this weekend and see how it goes before I try the oil pan.

Make sure you use the correct flux. Hardware store paste flux won't do it..........Bob

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12 hours ago, Bhigdog said:

It takes an acid type flux. Check out mcmaster carr. Several choices with good descriptions of suitability. Next day delivery......


Thanks! Didn't think to check Mcmaster... Have the catalog on the shelf!

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  • 2 months later...

Follow up here...


Turns out the filler/drain casting was not leaking at it's solder joint. It was a leak from the pan gaskets running down and collecting at the lowest point, the casting. Faked out a previous owner enough to smear RTV around it, almost got me too!


I filled the pan with lacquer thinner to just over the level of the casting solder joint and let it sit for an hour with no leak. I figured if oil out found a way out, the thinner would leak out extra fast. The pan is back on the car now, full of oil and not leaking a drop. 


The fix turned out to be high quality cork and felt pan gaskets instead of the poorly installed paper and felt old gaskets.

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