Technical Transmission leak. . . from flywheel?

[TheKGB]

This is becoming a nightmare. A few weeks ago, I purchased this ’71 500 L . It has the 126 (650cc) engine and 110F100 tranny with the 126 bell housing. I found this car in Miami. I bought it from an estate. It was stored for four years. It supposedly had a crate engine and transmission installed back then. The car was sent to a mechanic a month prior to my purchase. He changed the fluids and got it running.

I test drove the car and it performed flawlessly. I made the purchase and the car was transported by trailer to Atlanta the next day. I picked it up directly from the transport trailer and I drove it one and a half miles to my house. The car drove without issue. The next morning I could not get the car to start (yes, I checked for gas in the tank).

I called the previous owner for advice. He told me to continually crank the starter and eventually it would start. “Sometimes it takes a while” he said. I soon realized that the starter was burned up. I put the car in the garage and ordered a rebuilt starter that took five days for delivery. I installed the new starter this past Sunday. It turns over with plenty of power.

I still couldn’t get the car to start so I figured that it must be the timing. It has a 1-2-3 distributor ignition. I got the manual and followed the instructions, putting the car in fourth gear and pushed it to the timing marks for TDC. I set the LED on the ignition and supposedly the timing was now set. There is a spark but it still wouldn’t start. I put it in neutral and pushed it back into the garage. I figured it must be the carburetor and I would tackle that next week. The car has not moved since then.

The next evening, I got home and observed that there was a steady drip from the flywheel. It had never leaked before then. It appears to be oil from the transmission. After I shat my pants, I stuck a plastic bin under the drip. The next morning, it looked like most of it had drained out. I’ve attached some photos for your consideration.

I’ve been busy at work (seven days a week) and cannot tackle the problem until the new year. Your help and insight will be greatly appreciated.

 

[JumpJet]

What's your engine oil level look like? The most likely culprit is your rear main seal. Aside from the oil pan itself, there isn't much back there to leak oil. The transmission oil typically leaks forward of the flywheel from the axle seal area.

If it's your rear main, you'll need to remove the engine/transmission and separate the tranny to change it out.

 

[FR85]

What JumpJet said, have a smell of the oil, if it smells of petrol then it's engine oil but if it smells repulsive it's gear oil

 

[fiat500]

The next morning, it looked like most of it had drained out. I’ve attached some photos for your consideration.

If that is your engine oil then it's likely the sump was significantly overfilled.

If it's gear oil, it's likely that your gearbox was significantly overfilled.

Either that or there is a crack or split in a casing or the sump.

 

[FR85]

Very hard to overfill them unless the box was out and on its side.
Normally they overflow out of the fill hole when full I think.

Open the filler bolt on the side of the box and try filling it noting how much oil you started out with. There is no stick on the box.
Make sure you open the top one!!!

 

[fiat500]

Very hard to overfill them unless the box was out and on its side.

True, it's difficult even to fill it to the recommended level!
But all possibilities should be considered. That includes the possibility that the cause is something that someone else recently reported, in that petrol had got into the sump.

I would put money on too much engine oil when the mechanic changed the oil and as long as TheKGB can eliminate it as gear oil, that's easily confirmed by checking the dipstick. By the way, if the oil was changed and then you've only done a limited mileage on it, why does it look so dirty?

If you're unable to tackle the job for a month, I expect the leak will have stopped by then and the oil levels will point you in the right direction for a true diagnosis.

PS. Further thoughts: The rear main bearing seal is higher than the sump oil level, but I'm not sure that applies to the "O"-ring and/or gasket on the bearing carrier; so that's another potential leak point.

 

[FR85]

True, it's difficult even to fill it to the recommended level!
But all possibilities should be considered. That includes the possibility that the cause is something that someone else recently reported, in that petrol had got into the sump.

I would put money on too much engine oil when the mechanic changed the oil and as long as TheKGB can eleiminate it as gear oil, that's easily confirmed by checking the dipstick. By the way, if the oil was changed and then you've only done a limited mileage on it, why does it look so dirty?

Very true on getting oil into the box and not all over it!!

I had suggested petrol in the sump given the guy had been turning it over without it firing, normally excess fuel would sit in the cylinders and seep past the rings and get into the sump. Normally then there is a fuelly smell from the oil.
Gearbox oil, like diff oil then has it's own very tasty smell......hmmm yummy!!!

Oil could be black from the flinger filter, often overlooked. There is normally a good glump full in there when you crack em open.

Search the recent #fiat850 on Instagram and check out 850_spider_projects post on the flinger filter, nasty stuff!

 

[TheKGB]

I had suggested petrol in the sump given the guy had been turning it over without it firing, normally excess fuel would sit in the cylinders and seep past the rings and get into the sump. Normally then there is a fuelly smell from the oil.
Gearbox oil, like diff oil then has it's own very tasty smell......hmmm yummy!!!

Exactly! There is plenty of oil in the sump and it does smell of fuel. It is definitely gearbox oil which has it's own unique smell and different voscosity. It looks that a bit over a pint--maybe two pints-- drained into the bin.

 

[RalphM]

For so much to come out wile standing I would suspect the level was to high,
along with the fail to start could the diaphragm in the fuel pump be leaking?
if it as a engine driven pump that is.

 

[plasticpig1972]

Was the Level too high in the Sump because there is a problem with the Petrol Pump and Fuel has gone into the Sump:yuck:
Alan

 

[the hobbler]

I think that the problem could be as a result of the car having stood for a long time before Keith bought it. It is not unknown for the 'sealing-lip' on seals to stick to the shaft that they are sealing when everything is static for a long time (in this case, 4 years). When the car, and gearbox, are cranked into life and the appropriate shafts start turning, the 'lip' of the seal can get torn. Whilst the shaft is turning the seal will work to greater or lesser degree, but when the vehicle, and therefore the shafts, the oils leaks out.
I suffered this problem on a Mercedes car when I was running a M/Benz workshop. We collected (drove) the car from the customers house, a distance of about 8 miles, parked the car on a ramp in preparation for working on the car next day. When we opened up the workshop next day we were met with the sight of 2 large pools of oil under the car, from both the engine and the gear-box(auto). The customer had not thought it pertinent to tell us the car had stood static for 8 years! When the engine and gearbox were stripped to rectify the problem, the seals on both the crank shaft of the engine and the input shaft into the gear were torn with bits still stuck to their respective shafts
I would also be worried about the amount of oil that is in the catch-tray---the "dry, from new" capacity of the gearbox is only 2 Imperial (2.3 US) pints/1.1 litres, and the engine 3-1/2 Imperial pints.

 

[Toshi 975]

I think that the problem could be as a result of the car having stood for a long time before Keith bought it. It is not unknown for the 'sealing-lip' on seals to stick to the shaft that they are sealing when everything is static for a long time (in this case, 4 years). When the car, and gearbox, are cranked into life and the appropriate shafts start turning, the 'lip' of the seal can get torn. Whilst the shaft is turning the seal will work to greater or lesser degree, but when the vehicle, and therefore the shafts, the oils leaks out.

I think that you could be right with your first point about the car being left unused but for the oils to leak out past the crank seals then this will happen with a damaged seal and the oil is under pressure as in when the engine is running. For the oil to leak that much when static the oil level would have to raise several centimetres in the sump. The fuel pump diaphragm leaking badly is by far the most likely cause. With the high position of the fuel tank on the 500 the fuel will syphon to a lower point if allowed.