ford fiesta mk7 1.6 petrol metal gearbox vent

[brad6784]

Hello got a problem with my gearbox as it’s leaking oil out of the vent pipe, replaced the vent piece all together and still no luck

Ford fiesta mk7 1.6 ti-vct metal edition 2011

any help much appreciated
tia

 

[Handy Andy]

Usually the "vent pipe leak" is from too much oil in the housing - the transmission gears are churning in it and makes a lot of foam it can't tame down quick enough - so the volume then takes up too much room, it's (fluid) gets pressurized and flows out - the vent is the first to show this - but sooner or later the seals will also fail from this pressure making more of a mess.

The above is a TYPCAL IB5 vent - in the Fiesta we have a
sealed hole that routes to a tube and uses the same port this seal uses.
But, the housing at the other end - clips to the front radiator upper housing
ABOVE and to the FRONT of the engine - it's a little black box that holds
the fluid when it gets hot and expands, but stays contained and a vent allows
to keep air pressure to equalize pressure so the force of the expanding fluid
won't blow out a seal.

​

Oil does not usually foam - it has a foam reducing agent in it - but if the oil had not been changed ever or you don't even remember any mention of the transmission needing to be having its own oil changed - you might want to start asking a lot more questions to the mechanic that helps you with the housing replacement. This leak is a sign that more events are taking place - for oil to leak out, you're not putting oil in it to overfill this in the first place - so what is causing this problem of oil getting displaced? Sooner or later - that foaming and leakage - you're not going to have enough oil in there to protect the transmission and that lack of oil will make the transmission fail.

So, you replaced the vent piece - so that is the upper vent and expansion port, but the mess is leaking out, possibly at the vents seal on the housing or the whole seal at the vent on the transmission housing - so that will have to be looked at and replaced. It is on top of - highest point of elevation from the ground on the transmission housing.

IF the car got parked and then water came up and flooded the vehicle, it may signal water entry. Water displaces the fluid (oil floats on top) - this may be the indicator that it may be easier to change out the transmission than to fix the housing - else empty - drain out - all that fluid and then refill with 1.6L (Do not overfill) of any 75W-90 LSD (GL-4 or GL-5) Hypoid gear lube fluid (as I learned earlier) and see if the foaming causing the leaking fluid will cease.