Technical Mystery engine oil leak (Cinq 900cc)

Currently reading:
Technical Mystery engine oil leak (Cinq 900cc)


May 23, 2011
My L-reg Cinquecento has an oil leak that has coated the back of the engine and the inner driveshaft gaiters etc. Not nice! Looking up at the rear of the engine, one of the manifold studs seems to be very oily, yet the others are dry (see pic looking up at the back of the engine from underneath the car). I thought initially it was a leak from the rocker cover gasket, but as far as I can see above the manifold it's all dry. I wondering what the cause might be? As a side issue, the engine top end itself sounds very metallic and tappety almost as if it's being starved of oil. Could there be a connection? The car hasn't been on the road for some years and whilst I have recently changed the oil and filter, the previous owner neglected the car and I'm sure never serviced it. Is it possible an oilway to the valvegear is blocked and the oil is finding it's way out elsewhere?


  • cinq  oil.jpg
    cinq oil.jpg
    653.7 KB · Views: 148
Last edited:
Worth taking the rocker cover off and having a visual inspection. Im not familiar with the 899 but if you take the spray bar off the 1108 the oil should reach 6ft up in the air with engine running!

I think the 899 engines are a bit noiser and it may need adjustment?

Is the exhaust smokey at all?
Well, there's certainly no blue smoke from the exhaust, however there was a fair bit of white smoke when I last ran it up to temperature, but it was a very cold day. I've had several other cars with this same engine, so I'm pretty familiar with how they sound when they are happy, which leads me to suspect all is not well with this one. Hopefully removing the rocker cover will reveal more. I'm not sure what the arrangement is for feeding oil to the rocker gear on the 899cc. Maybe some bedtime reading with the Haynes manual is in order...
It'll be tappety because the oil is old/knackered.. and it probably hasn't been pumped around to the top end for a while, potentially.

I only had a Formula Uno (903cc) so my memory is hazy.. but the "leak" could be from the inlet manifold. If a lot of oil is being dumped into the airbox through the crank breather, it can pool in the airbox and then seep out at the gasket face where it sits on the caburettor (on my onld 903 at least).

Ralf S.
That stud goes into an oil gallery that feeds the rockes. It tends to leak after 20 years.
Remove the stud en put it back in with a thread sealing/locking compound.
The sound probalby comes from tired hydraulic tappets. You can buy new ones or change to mechanical rockers from the older 903cc engine's
I have both engine's in 2 different cinquecentos and the older 899cc is rattly on start up, I'm thinking your timing chain/sprockets may need changing as it can rattle on the timing cover when worn... the 1.1 engine is a fire unit with a timing belt and much quieter.