Technical Oil leak

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Technical Oil leak

dapedza

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Greetings fellow Fiat 500 enthusiasts.
I've taken the engine and gearbox out as I intend to fiat a 126 box (Mrs A isn't too keen to drive it without synchro).
Significant amount of oil in and around the bellhousing, and a lot of old oil all the way forward externally on the gearbox.
I'd think crankshaft oil seal, but the clutch is dry.
Any ideas?
Is it hard to get to the crankshaft oil seal?
Thanks! 20230425_102659.jpg20230425_102906.jpg
 
Greetings fellow Fiat 500 enthusiasts.
I've taken the engine and gearbox out as I intend to fiat a 126 box (Mrs A isn't too keen to drive it without synchro).
Significant amount of oil in and around the bellhousing, and a lot of old oil all the way forward externally on the gearbox.
I'd think crankshaft oil seal, but the clutch is dry.
Any ideas?
Is it hard to get to the crankshaft oil seal?
Thanks!View attachment 421853View attachment 421854
The last Fiat 500 I owned was in the late 1970s, however looking at the photos enlarged on my PC, does it look to you as if the oil mist which is dark like dirty engine oil rather than gear oil may be coming from the engine cooling fin area visible through the round vent above the flywheel so possible push rod seals or rocker cover gasket dripping down and then getting blown around the cooling fins/fan area?
There is oil within the bell housing, but if leaking from the clutch bearing slider shaft I would have expected it to get on the clutch, which your photo shows appears to be dry.
Another test would be to rub your finger on the oil in the back of the bell housing and compare it with the oil from the gearbox, I would smell it also as a guide.
I am not saying it's not coming from the crankshaft seal, as hard to tell without removing flywheel, however I would check the area I mentioned first.
Also where the cooling air is vented from the engine ducting can you check to see if any oil in that area?
 
The last Fiat 500 I owned was in the late 1970s, however looking at the photos enlarged on my PC, does it look to you as if the oil mist which is dark like dirty engine oil rather than gear oil may be coming from the engine cooling fin area visible through the round vent above the flywheel so possible push rod seals or rocker cover gasket dripping down and then getting blown around the cooling fins/fan area?
There is oil within the bell housing, but if leaking from the clutch bearing slider shaft I would have expected it to get on the clutch, which your photo shows appears to be dry.
Another test would be to rub your finger on the oil in the back of the bell housing and compare it with the oil from the gearbox, I would smell it also as a guide.
I am not saying it's not coming from the crankshaft seal, as hard to tell without removing flywheel, however I would check the area I mentioned first.
Also where the cooling air is vented from the engine ducting can you check to see if any oil in that area?
Thanks for getting back to me and for the information.
I've removed the flywheel to take a look.
To my uneducated eye, it would seem that the crank seal has been leaking. It may well be leaking from other areas.
It may be an idea to remove the cooling baffles as well?
 

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If the oil leaks from the flywheel side oil seal then the flywheel will act as a giant flinger which in turn will spread the oil but protect the clutch. They are not hard to get, I have four new ones on the table in front of me 😀
 
Thanks for getting back to me and for the information.
I've removed the flywheel to take a look.
To my uneducated eye, it would seem that the crank seal has been leaking. It may well be leaking from other areas.
It may be an idea to remove the cooling baffles as well?
Usually if oil seal leaking there would be a direct line/stain down from that area of back of engine casting/oil seal housing and also "flicking" outwards from the centre of the back of the flywheel from the source of the inertia outwards if you know what I mean.
It may still be a good idea whilst it is apart to check the inside of the cooling cowling/ducting as it may still have been blown in to the bell housing from a oil leak on the top of engine to me going by the oil /muck at the top vent hole above flywheel in your earlier photo.
Incidentally is that a crack in the starter ring gear or just a casting mark at the top of flywheel?
 
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I know one thing for sure that if the engine has been in use for a long while, which many have, then the insides of the tinware get very dirty through oil leaks and general crud which can include old spark plugs, sockets, nuts and bolts, all of which I have found in the bottom of the fan housing on different engines. When I rebuilt my old 500L engine and tidied up the tinware it was like an air freshener was blowing into the cockpit rather than stale oil.
 
Absolutely. Good advice. I'll get the tinware off, have a good look and give it a good clean. Interestingly, the back of the flywheel is as dry as a bone.
Looking down the tin cooling inlet shows a lot of filthy crud!
 
Absolutely. Good advice. I'll get the tinware off, have a good look and give it a good clean. Interestingly, the back of the flywheel is as dry as a bone.
Looking down the tin cooling inlet shows a lot of filthy crud!
If back of flywheel bone dry it sounds like the oil seal was doing it's job, especially if there was no visible oil trial down from bottom of oil seal area.
It was the first photos you posted, the one on the right that made me think oil was blowing in from that top vent hole above the flywheel especially as there was oil in the top cooling fins of the engine visible there.
 
Thanks, will carefully check the flywheel for cracks.

Tinware off. Absolutely filthy. I see the air duct has taken a massive hit, but I guess it should straighten out.

Anyhow, experts please tell me where the leak is from! What a mess! Thanks
 

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Yuk that looks pretty crudelicious 😳
looks to me like like the middle tube seal has been the culprit over I would guess a long period of time. New oil seals and the Haynes manual tells you how to rejuvenate the push rods tubes if they have compressed a bit. Happy cleaning🧹
 
Yuk that looks pretty crudelicious 😳
looks to me like like the middle tube seal has been the culprit over I would guess a long period of time. New oil seals and the Haynes manual tells you how to rejuvenate the push rods tubes if they have compressed a bit. Happy cleaning🧹
Certainly looks like it will account for the oil blowing into the bellhousing.
Re the flywheel possible ring gear crack, I would just give it a light tap with a screwdriver and hammer, hopefully it's only a casting mark, but that should soon tell you.
If it is the ring gear , it isn't that hard to fit onto the flywheel if they are still available, most older mechanics have fitted 100s over the years, we used to saw partly through the old one, give it a wallop with a chisel to remove, then heat up the new ring gear with Oxy/acetylene torch, though you can do it with propane, drop it on and give it a tap with a chisel to make sure it is on square, then let it cool down.
I did notice the starter has given the teeth a bit of a battering over the years anyway, one thing modern pre engaged starters don't suffer from.
 
Certainly looks like it will account for the oil blowing into the bellhousing.
Re the flywheel possible ring gear crack, I would just give it a light tap with a screwdriver and hammer, hopefully it's only a casting mark, but that should soon tell you.
If it is the ring gear , it isn't that hard to fit onto the flywheel if they are still available, most older mechanics have fitted 100s over the years, we used to saw partly through the old one, give it a wallop with a chisel to remove, then heat up the new ring gear with Oxy/acetylene torch, though you can do it with propane, drop it on and give it a tap with a chisel to make sure it is on square, then let it cool down.
I did notice the starter has given the teeth a bit of a battering over the years anyway, one thing modern pre engaged starters don't suffer from.
Good spot everyone. Sure enough, the ring gear has a crack running all the way through😢 any ideas on who might supply this?
 
I see that Ricambio have them £49 + vat. I looked back at your flywheel picture to see the crack and noticed that I have a new replacement clutch for your car just in case you are thinking of replacing it while it is all apart.
 
Good spot everyone. Sure enough, the ring gear has a crack running all the way through😢 any ideas on who might supply this?
If you haven't fitted one before, may I suggest first checking if there is a lead in on the teeth for the starter gear and make sure that you fit it in the same direction.
Your old ring gear if it is split as I suspected, it should just knock off with a few blows from a cold chisel, however when you come to fitting the new one, may I suggest the flywheel is firmly seated on the ground so it doesn't wobble, then the new ring gear is supported on three fire bricks or similar and ideally use a large oxy/acetylene torch gentle going around the gear until uniformly a good dull red, then with a couple of large pairs of pliers or similar (not molegrips as you want to release quickly) align the ring gear over the flywheel and drop into place, where it should be quite loose for a few seconds giving you enough time to turn it slightly with a screwdriver or chisel to ensure it is happily sat in the correct position, if so you may quench it with water.
In the unlikely case of it being out of position knock it off quickly whilst still hot and expanded and re do the procedure, don't let it cool down in the wrong place.
If no oxy/acetylene torch I have done it with a big propane torch (not a toy with the throw away canisters) and what ever you do , do not try to cold press the gear on.
Any other old school mechanics with further suggestions I may have missed?;)
 
If you haven't fitted one before, may I suggest first checking if there is a lead in on the teeth for the starter gear and make sure that you fit it in the same direction.
Your old ring gear if it is split as I suspected, it should just knock off with a few blows from a cold chisel, however when you come to fitting the new one, may I suggest the flywheel is firmly seated on the ground so it doesn't wobble, then the new ring gear is supported on three fire bricks or similar and ideally use a large oxy/acetylene torch gentle going around the gear until uniformly a good dull red, then with a couple of large pairs of pliers or similar (not molegrips as you want to release quickly) align the ring gear over the flywheel and drop into place, where it should be quite loose for a few seconds giving you enough time to turn it slightly with a screwdriver or chisel to ensure it is happily sat in the correct position, if so you may quench it with water.
In the unlikely case of it being out of position knock it off quickly whilst still hot and expanded and re do the procedure, don't let it cool down in the wrong place.
If no oxy/acetylene torch I have done it with a big propane torch (not a toy with the throw away canisters) and what ever you do , do not try to cold press the gear on.
Any other old school mechanics with further suggestions I may have missed?;)
If you haven't got access to an oxyacetelene ( or as Toshi suggests, a BIG propane) torch, have a word with your local blacksmith. Up here in North wales (just outside Chester) we have a local blacksmith who has done this job quite a number of times for me---including on Ferrari flywheels. He charges just £30 a time
 
Thanks folks. I’ll take your advice. Stick the flywheel in the freezer overnight. I’ve got a good propane torch. Will give it a go(y)
 
All went well. Heated the new ring and it went on easily enough with a copper hammer. Still not convinced the old one is cracked- could have been a manufacturing defect. But it’s not worth the risk.
Changed the pushrod tubes, new oil seals & a new clutch. Hope it no longer leaks 🤞
 

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All went well. Heated the new ring and it went on easily enough with a copper hammer. Still not convinced the old one is cracked- could have been a manufacturing defect. But it’s not worth the risk.
Changed the pushrod tubes, new oil seals & a new clutch. Hope it no longer leaks 🤞
At the beginning I did say "Incidentally is that a crack in the starter ring gear or just a casting mark at the top of flywheel?" Normally if you tap it with a chisel if cracked and loose it will sound different and try to move.
Having said that, it was probably a good idea to change it as the teeth where the starter engage were showing signs of wear.:)
 
At the beginning I did say "Incidentally is that a crack in the starter ring gear or just a casting mark at the top of flywheel?" Normally if you tap it with a chisel if cracked and loose it will sound different and try to move.
Having said that, it was probably a good idea to change it as the teeth where the starter engage were showing signs of wear.:)
In the scheme of things, it was cheap & easy to replace. Plus there is peace of mind. To have the ring gear fail, it would no doubt make a real mess & would involve a tow truck. I remain hugely grateful for the good advice on this excellent forum!👍
 
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