General Fiat 500 gearbox oil leak

[Sarahfallon]

Hi I’ve noticed oil on the drive and on closer inspection theres a lot of oil on the top of my gearbox. The cap I’ve circled on the pic (isn’t my car, it’s from Google) is very loose. I’m wondering
1) what the cap is called?
2) whether I can replace it?
3) Could there be a bigger issue on why it’s loose or popped?
4) Is it safe to drive?

Thankyou

 

[Pugglt Auld Jock]

Hi I’ve noticed oil on the drive and on closer inspection theres a lot of oil on the top of my gearbox. The cap I’ve circled on the pic (isn’t my car, it’s from Google) is very loose. I’m wondering
1) what the cap is called?
2) whether I can replace it?
3) Could there be a bigger issue on why it’s loose or popped?
4) Is it safe to drive?

Thankyou

Unless I'm much mistaken that's the breather. The gearbox needs to be able to equalize internal air pressure as it heats up and cools down in use, That wee cap allows air to exit the box as it heats up and re-enter as it cools. If it couldn't do this you'd get oil leaking out of places like driveshaft seals as the box heats up in use. I can't remember if the one on ours seems loose but it's not unusual for them to be able to jiggle about a wee bit so they keep clear of blockages?

On these boxes the little seal where the gear selector rod exits the box nearly always leaks a little as they age. Pretty much every one I've ever seen leaks slightly from it. If the leak is small enough that it doesn't run down the outside in any quantity I just tend to live with it. Becky's has leaked all the time I've owned her and the level drops so little when I check her at the yearly service that sometimes it doesn't even need a top up. The last one I did was on my boy's 2012 Punto 1.4. It involves removing the top cover which is held on by the bolts you can see in the picture you've posted. There's a quite tight roll pin to drive out too but it's all very doable if you have some experience of working on cars. Maybe not a job for a complete novice?

By the way, if you're under the car, maybe doing a service etc, and you notice what looks like an oil leak from the N/S driveshaft seal then take a very careful look at the selector seal. It might just be that there's oil leaking down the side of the box and around the N/S driveshaft seal and you are mistaking this for a driveshaft seal leaking. I've been fooled by this before.

 

[John202020]

It's more likely the sump or its seal that's leaking?

 

[Pugglt Auld Jock]

It's more likely the sump or its seal that's leaking?

If there's a lot of oil leaking maybe the OP should remove the G/Box level plug and see how much oil is in there?

 

[Sarahfallon]

Unless I'm much mistaken that's the breather. The gearbox needs to be able to equalize internal air pressure as it heats up and cools down in use, That wee cap allows air to exit the box as it heats up and re-enter as it cools. If it couldn't do this you'd get oil leaking out of places like driveshaft seals as the box heats up in use. I can't remember if the one on ours seems loose but it's not unusual for them to be able to jiggle about a wee bit so they keep clear of blockages?

On these boxes the little seal where the gear selector rod exits the box nearly always leaks a little as they age. Pretty much every one I've ever seen leaks slightly from it. If the leak is small enough that it doesn't run down the outside in any quantity I just tend to live with it. Becky's has leaked all the time I've owned her and the level drops so little when I check her at the yearly service that sometimes it doesn't even need a top up. The last one I did was on my boy's 2012 Punto 1.4. It involves removing the top cover which is held on by the bolts you can see in the picture you've posted. There's a quite tight roll pin to drive out too but it's all very doable if you have some experience of working on cars. Maybe not a job for a complete novice?

By the way, if you're under the car, maybe doing a service etc, and you notice what looks like an oil leak from the N/S driveshaft seal then take a very careful look at the selector seal. It might just be that there's oil leaking down the side of the box and around the N/S driveshaft seal and you are mistaking this for a driveshaft seal leaking. I've been fooled by this before.

Thankyou so much for your reply I will take a look. Hopefully it’s like the ones you’ve had and just something that happens but never causes a problem!

 

[Sarahfallon]

If there's a lot of oil leaking maybe the OP should remove the G/Box level plug and see how much oil is in there?

I will check it tomorrow, thankyou

 

[Sarahfallon]

It's more likely the sump or its seal that's leaking?

Thankyou I will have a look tomorrow!

 

[rmjbn1]

Hi As above, don't attempt to remove that circular plastic breather cover!

It's fine if it's loose, trying to remove it risks breaking it.

Yes car is safe to drive, but

Gearbox oil needs to be up to level.

I think it's very important you keep checking oil level (and all fluid levels!) and keep it topped up until you know how quickly it's losing oil.

If it's only losing a small amount I would live with it.

12mm hex filler plug on the front of the gearbox, oil needs to be up to the level of the hole with the car on level ground.

Only use the grade of oil specified in your manual.

Let us know if you have any questions, plenty of friendly knowledgeable folk on here

Fingers crossed leak isn't too bad

 

[rmjbn1]

What engine do you have?
Is the car manual or automatic?

 

[Sarahfallon]

What engine do you have?
Is the car manual or automatic?

It’s manual 1.2

 

[Sarahfallon]

Hi As above, don't attempt to remove that circular plastic breather cover!

It's fine if it's loose, trying to remove it risks breaking it.

Yes car is safe to drive, but

Gearbox oil needs to be up to level.

I think it's very important you keep checking oil level (and all fluid levels!) and keep it topped up until you know how quickly it's losing oil.

If it's only losing a small amount I would live with it.

12mm hex filler plug on the front of the gearbox, oil needs to be up to the level of the hole with the car on level ground.

Only use the grade of oil specified in your manual.

Let us know if you have any questions, plenty of friendly knowledgeable folk on here

Fingers crossed leak isn't too bad

Thankyou for that. I have topped it up, doesn’t seem to have lost much.
Everyone is so knowledgeable on here, i have a Haynes manual but it doesn’t speak in female language

 

[rmjbn1]

Well done on topping up the gearbox. Good to keep these little cars well lubricated and happy

I would keep checking the level again once a month for the next 3-4 months and see if it drops.

I would also clean the oily top of the gearbox so you can see if it comes back.

There are tins of engine degreaser you can get, but an aerosol can of brake cleaner can be used and is a very useful thing to have.

Gear oil has a very distinctive strong smell if that helps you figure out what is leaking.

Or take a picture, might tell us something.

 

[rmjbn1]

Other possible leaks in that area are:
Engine oil from the rocker cover, or
Clutch fluid from the slave cylinder on top of the gearbox.

How are levels of:
Engine oil
Clutch fluid (small round plastic reservoir)
Brake fluid
Coolant

Again, let us know if you need any help with these (coolant level can be hard to read on some engines), we can point you in the right direction

 

[Sarahfallon]

Other possible leaks in that area are:
Engine oil from the rocker cover, or
Clutch fluid from the slave cylinder on top of the gearbox.

How are levels of:
Engine oil
Clutch fluid (small round plastic reservoir)
Brake fluid
Coolant

Again, let us know if you need any help with these (coolant level can be hard to read on some engines), we can point you in the right direction

I checked my engine oil, clutch fluid and they are good. No idea where the brake fluid is and yeah the coolant is a pain to see, I do it in the dark with my phone torch and that seems ok too

 

[rmjbn1]

Brake fluid is here, right back of engine bay, behind the battery.
Blue arrows show min max levels

 

[Sarahfallon]

Brake fluid is here, right back of engine bay, behind the battery.
Blue arrows show min max levels
View attachment 469663

Fab thankyou. I will go and check that out after work

 

[rmjbn1]

Oh I'm sure it's nothing to do with the leak you've found.

Just one of those things to check the level and condition of every now and again.

If brake/clutch fluid is cloudy it needs changing (supposed to be changed every two years as it absorbs moisture, but nobody does)

 

[Pugglt Auld Jock]

Thankyou for that. I have topped it up, doesn’t seem to have lost much.
Everyone is so knowledgeable on here, i have a Haynes manual but it doesn’t speak in female language

That sounds good. Our Becky, with the 1.2 engine, has a small leak from the gear shift where it exits the box which makes it look "mucky" However she only rarely needs a top up. Maybe an egg cup full once a year if that. A little oil makes a bigger looking mess than you think.

Yup, there's a lot of knowledge on here and some very nice people to advise you - Doesn't speak female? 55 years of marriage, to the same girl, has helped me a lot but you guys still mystify me sometimes!

PS. gear oil has a sort of sulphury - bad egg - smell where as engine oil does not. Engine oil when new out of it's container often smalls a wee bit like unscented washing up liquid I think? Very different to gearbox oil, which is good because once you know what they smell like it helps to decide whether it's the box or the engine which is leaking.

 

[Pugglt Auld Jock]

I checked my engine oil, clutch fluid and they are good. No idea where the brake fluid is and yeah the coolant is a pain to see, I do it in the dark with my phone torch and that seems ok too

Check the brake fluid level in the same way - ie by looking through the plastic reservoir. Don't take the top off the brake or clutch fluid reservoirs unless you need to top up (some cars have just one reservoir shared by both clutch and brake systems) Why not? because brake fluid is hygroscopic - which means it absorbs moisture from the air. This is a bad thing as water in the brake fluid eventually increases the rate of corrosion of the components in the braking system which might lead to costly repairs and eventually, when the concentration gets high enough can actually affect the performance of the brakes to a dangerous level. Changing the fluid is not as simple as just sucking out the contents of the reservoir though and you'll need someone with mechanical knowledge or a garage to do it properly. It's generally accepted that brake fluid should be renewed every 2 to 3 years but it's one of the most neglected service tasks and absolutely loads of people don't do it. Although a recommendation it's seldom done without you specifically asking for it. I've found main dealers will sometimes try to sell it to you but smaller garages not so much. A garage with a power bleeder will do it very quickly, less than half an hour if all goes well. The one unpredictable factor is the bleeders, which are like small bolts, are often rusted up on older cars and can snap off which will most likely result in the garage fitting a new brake part which adds substantially to the cost. Not a good reason to ignore this safety related task though. Brake fluid in good condition is almost transparent with sometimes a slight golden colour. When it gets old and contaminated it gets much darker and is very definitely not see through. Most cars take DOT4 brake fluid - It's often written on the reservoir cap of reservoir itself. This is also by far the most common brake fluid stocked by suppliers but there are others, not all of which are suitable or will mix, so be sure to get the right stuff for topping up. Also, don't fill above the full mark or it can make things more difficult when brake overhaul work is required. I look at mine every time I open the bonnet and if it's approximately or only very slightly lower than last time I checked it then I'm happy between the two marks and not too near the bottom mark is fine. It will drop very slowly as the brakes wear with age and use. Any sudden drop needs IMMEDIATE investigation - There's not much fluid in the system and if it all leaks away then, oops Mum, NO BRAKES!

One of the most useful things you can do, whether you're going to do some of the work on the car yourself or not, is to find a local Fiat/Alfa Romeo/Italian car specialist so you'll be ready if, one day, you need them.

 

[Ralf S.]

Hi I’ve noticed oil on the drive and on closer inspection theres a lot of oil on the top of my gearbox. The cap I’ve circled on the pic (isn’t my car, it’s from Google) is very loose. I’m wondering
1) what the cap is called?
2) whether I can replace it?
3) Could there be a bigger issue on why it’s loose or popped?
4) Is it safe to drive?

Thankyou

Oil leaks that drip onto the floor can fail you an MOT these days.. seems like we can take oil out of the environment, but we're not allowed to put it back..

If you look under the car (put it on an axle stand.. don't do it with the car just on the jack) have a look at the join between the clutch bell-housing and the engine .. right next to where the black metal sump pan ends. If you have oil collecting there, before it drips, then you either have a crankshaft seal leak or the gearbox input shaft seal is leaking.

If the oil is quite thin and smells of oil, then it's the crankshaft seal. If the oil is thicker and smells of fried bacon, then it's gear oil.

Whichever one it is will need the gearbox to be removed, so if possible (i.e. it's not so bad to have Greta on your case)then get it replaced when you next replace the clutch, so you'll only be paying a bit extra (seal and labour) rather than £200 labour to fit a £20 seal).

Keep an eye on whichever oil it is, to make sure the level doesn't get low.


It could also be an overfilled gearbox.. so with the car level, just remove the gearbox oil filler plug and hopefully nothing will gush out. If it does, just let it stop and then the gearbox level will be correct. It's the one on the front of the gearbox, pointing upwards 2.. or 10 o'clock position) not the drain plug which is facing downwards.



Ralf S.