Technical Oil pan gasket leak

[Marvin 1973 500]

Hello all. I am having a frustrating time trying to eliminate an oil leak at the oil pan gasket. I have replaced the gasket two times, and it still persists. It originates along the side which is behind the flywheel. When it leaks, the oil is blown around by the flywheel and the cooling system. The transmission bell housing area will eventually get a coating of oil. Not good to have in the clutch area.


I clean the bottom of the engine case with solvent, as well as the pan contact area. I checked the pan for flatness, and it seemed OK. The bottom of the engine case has a few scratches from the previous owner, so I have been using a thin film of black RTV sealant on the engine case surface, both sides of the gasket, and the pan contact area. I am using those thick, (tan centered) spongy type of oil pan gaskets. I tighten the screws evenly in a cross pattern until they all seem to give the same tightness. I am careful not to go too far, and squeeze the gasket so that it appears to bulge out.


All is OK at first, but then the leak starts in the same area after running for a day or so. The drips on the floor originate along that flywheel area. When I check the screws, they are no longer snug, and I have to tighten them again. It seems like the gasket has yielded?? I am using the oval washers and a split washer on top of that, so they should not loosen. The leak slows a little bit after retighteneing, but eventually it is back to the same amount.


I have used a rubber type, or a paper gasket, on other engines, along with the RTV sealant and have never had a serious problem. If a surface had scratches, I filled them in via epoxy and scraping off all excess with a razor blade. Gets me back to a flat surface. Has anyone else had this kind of problem? Have you used a paper gasket or other material with any success? I have one new spongy gasket left to try. Thanks in advance.

 

[Franko500]

I had 2 leaks, the oil found its way through the thread of 2 bolts. These are the ones where the threaded hole goes right through into the crank case. I had to put sealant on the thread to seal them.

 

[Vitesse]

Have you tried Permatex 82194 Ultra Grey RTV silicon gasket, as recommended by Peter (Fiat500) on the forum. I have used it on my sump to stop the same sort of leaks and also I recommended it to a friend of mine whose supercharger kept leaking on his Mini and it cured that as well.

It's US made so you shouldn't have a problem getting hold of it.

Tony

 

[Damon500]

Hi Marvin, if you are having a lot of oil sprayed around the bell housing it is usually caused by the rear crankshaft seal leaking. Or in some cases (more likely on the 650 engines) the rear main bearing can come loose causing a leak along the rear of the sump. In both cases it is either and engine out or gearbox out job to fix.

It is normal for the rubberised cork gaskets to compress slightly, using RTV on the gaskets often causes more problems as the gasket material tends to squash out.

The best solution I have found is to put the gasket on dry with no sealant at all and the rubber bonds to the sealing surfaces. Make sure you have absolutely no oil on either and tighten the bolts until the gasket just begins to squeeze then stop.

Also start tightening from the centre of each side of the sump and work your way to the corners.

Don't worry if the bolts are not 'tight' as this will often split the gasket, I just use a dab of thread locking compound on them so they don't come loose.

 

[fiat500]

Alternatively, I use light-duty threadlock adhesive on all of them; that also means that they are less likely to come loose without the need to over-tighten them.

 

[the hobbler]

Totally agree with Peter and Damon----use the 'rubberoid' gasket (NOT the cork one), and a light smear of locktite on all the threads. When I put my 'Abarth' sump on, I retained the Fiat washers and used cap-head stainless bolts and did the bolts up evenly (initially 'dry') until I could see the gasket JUST beginning to squeeze out. I then took the bolts out, one at a time, smeared the thread with Loctite and replaced them. The one place my engine doesn't leak is the sump gasket!

 

[Marvin 1973 500]

OK I will give it a try, as I have one new "rubberized" gasket to use. Did you use any type of sealant, or just merely clean all surfaces (including the gasket) very well with solvent, and using ONLY the rubberized gasket? In addition to the Permatex grey RTV, I had read elsewhere that some mechanics had used a red, Permatex high tack adhesive to make a seal and hold the rubber gasket in place. Thanks.


By the way, the engine and transmission are out of the car for the 3rd time -- for a different reason (I will eventually post about that later.....), and as a result, I have carefully looked for the source of the leak over these number of weeks. I thoroughly checked to see if there was a leak at the main rear bearing seal under the flywheel, or at the housing, etc. (as I had the flywheel off). Everything was OK. No oil observed at all. Also no leaks at the head gasket, pushrod tubes, valve cover, etc.


I do agree with oil following the threads for the two sump bolts that extend up to the main rear bearing. Deep inside, you can see the threads of the bolts holding that bearing housing in place. I thought at the time, hmmm......, if oil in the case follows the threads of those two bolts of the bearing housing, it can then follow the threads of the bolts securing the sump. Those sump threads were quite worn from the previous owner, and cleaning up the threads with a tap left the bolts engagement quite sloppy. Rather than use an insert, I went ahead and drilled them out with a 6.9mm 17/64 drill bit for an 8mm 1.25 tap. After cleaning everything out, I then placed some epoxy sealant up in there at the end, so those threads from the bearing would be covered and sealed. The 8mm bolts fit nice and snug. The leak no longer originates from there, but rather next door for the 6mm bolt at the corner on the fan end. I will check the fit of that 6mm bolt, and perhaps change it to an 8mm.


The sad thing about having a leak at that area of the sump where the flywheel is located, is that the oil drips get blown about by the cooling system and the flywheel itself. Having the flywheel cover on merely adds to the problem, by ensuring that the oil gets spread about inside the transmission bell housing and clutch area. Frustrating!!

 

[rickypoos]

Totally agree with Peter and Damon----use the 'rubberoid' gasket (NOT the cork one), and a light smear of locktite on all the threads. When I put my 'Abarth' sump on, I retained the Fiat washers and used cap-head stainless bolts and did the bolts up evenly (initially 'dry') until I could see the gasket JUST beginning to squeeze out. I then took the bolts out, one at a time, smeared the thread with Loctite and replaced them. The one place my engine doesn't leak is the sump gasket!

Can you please help. I have changed my rubber gasket 3 times and I still get leaks on the LHS. Wondered exactly where are the 2 bolts some members have mentioned that open up inside the crankcase and might cause leaks if not sealed properly as I suspect that could be my problem rather than me either having under-tightened or over-tightened the bolts!!. Need to understand which bolts to put the Loctite on!!! Desperate! Thanks

 

[Kiltedboarder]

Evening all
Does anybody have a link as to where I can buy a rubber oil pan gasket. I can only seem to find cork ones and they have always been a source of leaks for me

Thanks

 

[rickypoos]

Evening all
Does anybody have a link as to where I can buy a rubber oil pan gasket. I can only seem to find cork ones and they have always been a source of leaks for me

Thanks

I got mine from Julcar in Italy. I live in France so the delivery from Italy is no more than from my usual suppliers in Germany and Holland. Can you confirm which 2 bolts need Loctite. I have assumed it is the two nearest the rear main bearing. Is that correct?

 

[the hobbler]

Evening all
Does anybody have a link as to where I can buy a rubber oil pan gasket. I can only seem to find cork ones and they have always been a source of leaks for me

Thanks

D'angelo Motori (Italy)---part number:--D3225--rubber sump-gasket E10 plus IVA and postage OR, they also market a kevlar sump-gasket forjusta few euros more.The 'rubber' gasket should suffice.