Hi there I have my mums fiat 500 and noticed it had no oil so
i changed the oil and filter and cleaned up the engine to see where the leak was coming from and I found that it is coming from a small vent hole on the middle of the valve cover could anyone tell me why this is happening and how I can resolve the problem any help would be very much appreciated i have included a pic

Hi and welcome what engine is this and what year?

Hi there its a 2017 fiat 500 with the 1.2 fire engine im sorry but I don't know the exact code.

My mistake it's in the title, is it possible a breather hose is missing?

Not that I'm aware of you can't see it when the air filter is back in place and the only breather hoses are at rear of engine leading to air filter.

It's obviously leaking out of that bung in the middle.
Strange though as I haven't seen a plastic rocker cover on one of these engines, they must have only started fitting these in the last few years, all the one's I worked on have had alloy covers.

I can't find a part listing or diaghram for that cover, but I reckon it's either damaged/cracked or the bung in loose or there's a failed O ring in it.

It could be the tube/bung is some sort of oil feed to send oil up to lube the valve train, it could have a gauze filter in there to strain out the oil (which would explain the access the bung provides), if that's clogged it might force the oil out.

Hi there its got a vvt solenoid on the rocker and I've had the rocker off but there's a plastic shield inside and also 4 holes with rubber o rings that coincide with 4 oil holes in the head other than that it doesn't look like you can separate these parts to have a look.

Not sure if these help:

https://www.fiatdalys.lt/en/catalog...CMBBZ,CMBGSL/GDX/crankcase-and-cylinders-head

I've ordered up a new rocker gasket that comes with 4 oil seal for inside the cover i will strip it back down Sunday replace thise o rings and fire some brake cleaner through all the Chambers to make sure there is no crud or blockages in there then see if that makesna diffrence.

varesecrazy said:

Not sure if these help:

https://www.fiatdalys.lt/en/catalog...CMBBZ,CMBGSL/GDX/crankcase-and-cylinders-head

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They aren't showing the latest rocker cover on there, just the alloy ones.
There are some plug/bungs listed but those too come back as metal ones.

Looking at the cylinder head, oil is pumped up through a hole in it and into that tube moulded into the rocker cover (centre of pic), past the leaking bung and into the top of the inside of the rocker cover.
It'll then spread the oil out along the inside/underside of the rocker cover so it lubes up all of the camshaft like a spray bar.

The plastic around that bung has either broken (has someone over tightened it?), the bung come loose or just cracked for some reason.

The car has only done 17000 miles so as far as I'm aware was getting serviced at dealers the last few years .

The rocker cover didn't seem over tightened when I took it off and I retightened to 8nm

Hi i took it apart Sunday and changed rocker cover and the 4 O rings inside the cover i also blew out all the passages with compressed air and looked about the leaking bit but it looks like it could be a pressure relief valve and its still leaking .

Saf22 said:

Hi i took it apart Sunday and changed rocker cover and the 4 O rings inside the cover i also blew out all the passages with compressed air and looked about the leaking bit but it looks like it could be a pressure relief valve and its still leaking .

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I doubt it's a pressure relief valve that relieves all over a hot exhaust manifold!
The cover/engine is vented the other side, the pipe is plumbed in under the airbox.

The older cars had a alloy cam cover and within that are some blanking plugs that look similar to the plug in the centre of the image, except the alloy covers blanks are alloy not plastic, which your appears to be.

The oil is obviously leaking out of or around the plastic plug with the allen key slot in it in the centre of the image, so it's either loose, the seal is perished or missing or the casing around it has cracked.

It's possible if it leaked before you got it, the last owner might have over tightened it and crack something.

I would be tempted to "test" the plug, get the right size allen key in it and put a little anti clock wise pressure on it first to see if it's loose and then a little (Very little) clock wise pressure while checking if the case around it flexes or moves showing up a crack.

I believe the alloy blanking plugs in the alloy cam covers just have some thread seal on them, but without a current parts list I couldn't tell you if there's a O ring behind the plastic ones.

The oil behind the blanking plug is pumped up from the bottom of the engine under some pressure to lube the cam, so any small crack or weak seal and the oil will find it's way out.

Saf22 said:

The rocker cover didn't seem over tightened when I took it off and I retightened to 8nm

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So when you had the cover off was there a hole on the inside of the cover that the bung fills? if yes, wash the cam cover fully degrease it, then fill the rear of the hole with silicone sealant, allow it to cure for at least 24 hours then replace it, probably last forever?

Though that doesn't explain why its started leaking?

SAF. Did you resolve this issue?
I have the same problem.
I have the cam cover off and a new seal kit but the bung that leaks does not come off and doesn’t seam to have a seal.
To make things worse, we are in lockdown so fiat repair centres are not open to help either.
Internally the leaky bunge is fed by oil pressure via the gallery that then supply’s all your valves so sealing from the inside looks impossible.

No never got to the bottom of it found a valve cover for sale but the price was excessive so tried to instant gasket the hole but it was still leaking so just left it leaking. The car is due service and mot in JANUARY so will give it another bash then ? if you find a solution please share.

Having only owned and worked on rather older cars, I didn't know Fiat had started using a plastic cam cover on the FIRE engine. A massive retrogressive step in my opinion. Your experience here is another excellent reason why plastic should not be used for these components. My boy's Astra has a much larger cam cover for the twin cam engine in his Astra. It leaks too and I've discovered it's a well known problem due to the cover distorting over time - it has a nasty habit of filling up the plug wells with oil, causing miss fires and eventually the demise of the coil pack! The only cure is to replace the cover - I believe they are not cheap, hundreds of pounds?! His has had a new gasket fitted and a whole load of sealant. It's not leaking just now, but we know it's only a matter of time.

I'm frequently hearing of problems with distortion of plastic parts, Thermostat housings, inlet manifolds, cam covers and so on and it's only going to become a bigger problem as these vehicles age. But, oh silly me, they don't want these things to last do they!

PS Wonder if "the Mick/Mike's" at S4p could help with a cheaper pattern part from one of their Italian suppliers?

A plastic rocker ….. what!!? Now that’s put me off a newer 500 thank god I’ve got an oldie!

Pugglt Auld Jock said:

Having only owned and worked on rather older cars, I didn't know Fiat had started using a plastic cam cover on the FIRE engine. A massive retrogressive step in my opinion. Your experience here is another excellent reason why plastic should not be used for these components. My boy's Astra has a much larger cam cover for the twin cam engine in his Astra. It leaks too and I've discovered it's a well known problem due to the cover distorting over time - it has a nasty habit of filling up the plug wells with oil, causing miss fires and eventually the demise of the coil pack! The only cure is to replace the cover - I believe they are not cheap, hundreds of pounds?! His has had a new gasket fitted and a whole load of sealant. It's not leaking just now, but we know it's only a matter of time.

I'm frequently hearing of problems with distortion of plastic parts, Thermostat housings, inlet manifolds, cam covers and so on and it's only going to become a bigger problem as these vehicles age. But, oh silly me, they don't want these things to last do they!

PS Wonder if "the Mick/Mike's" at S4p could help with a cheaper pattern part from one of their Italian suppliers?

Click to expand...

I’ve been busy replacing plastic parts and rubber .. in the engine bay I replaced my thermostat earlier in the year with one that has a metal pipe instead of the plastic pipe that breaks I’ve also replaced my oil breather pipe with a rather well made silicone pipe that has a lifetime guarantee (apparently) keeping proactive with my pipes before they fail!