Hi, I'm removed the throttle body on my 500 1.2 to clean it out and I've noticed a split in what looks like a vacuum hose.
Its a thin hose that connects the airbox to the inlet manifold (not the thick breather hose between the cam cover and the airbox)
However the spigot where this pipe joins the inlet manifold is a dead end. I've tried sucking on the pipe and no air came through and even tried blowing compressed air down and none escaped.
Confused by this I had a look inside the inlet manifold with one of those "little mirror on a stick" things and this confirmed it - at the place where it looks like air should come in to the inlet manifold i.e where the spigot enters the IM its just blank. It looks very original - the plastic just covers over the moulding without any drilling to let air pass.
Were these manifolds used on different models and perhaps the vacuum hose isn't required on the 500?
If they wanted to blank it off why did they bother attaching a hose to it?
This car was bought brand new from the Fiat dealer in 2010 and I am the only owner so its not like somebody has modified it.

My question is : should I bother replacing a hose that goes to nowhere?
It would be easier to simply cut the hose before the split part and blank the remaining bit connected to the airbox with a bolt or something.

I can add some pics to clarify if needed
Thanks in advance

This is where the small pipe joins the airbox. The small one going into the side of the breather.



Now this is underneath the car looking upwards at the underneath of the inlet manifold.
Where I have attached the green vacuum pipe to do a suction test is where the other end of the split pipe used to go.



This is looking into the inlet manifold after having removed the throttle body. You can see the indentation where the vacuum pipe would enter.


And now (using my trusty mirror) you can see that there is no drilling in this indentation for air to pass through. Its just blank.


So can someone explain why Fiat have fitted 2 vacuum ports and a vacuum hose connecting them together if they have no purpose? And with that in mind do I even need to replace the split vacuum hose - I could just cut it and block it with a bolt to stop unfiltered air from entering at the airbox end. Any thoughts?
Thank you.

Anyone know?

tashman said:

Anyone know?

Click to expand...

What year. There were a few threads covering repairs to snapped airbox fittings on earlier 500s.
have done Search in 'advanced'.?

Charlie.Oxford

Yes I did do many searches before writing my post.
Many others on this forum have asked the same question, but nobody has yet received a satisfactory answer.

Everybody knows what the large breather hose does, but nobody can explain the purpose of the small one, or why it leads to a dead end?

A clue to its pointlessness might be that if you buy a K&N induction kit they supply you with a 'plug' to block off the small hose altogether.

The car is year 2010 which I put in my first post.

Not sure if it helps, but on the wife's 59 plate 1.2 the hose does provide some function, as I had to replace it, as it was split near the top, spraying gunk onto the firewall, so rather than vacuum it maybe a vent/breather?

Very interesting....
I just stumbled across this post.
My daughter’s car is exactly the same (a 2011 Ford Ka actually).
It’s been running rough and I was trying to fix it.
I also found this as well – no hole in the plastic.
However, I thought it was blocked and eventually manage to make a hole.
Now I’m wondering if I should block it again…
As tashman says what’s the point of fitting a hose that eventually splits if it leads nowhere (and has a little tee piece that often snaps off!).
Was an explanation ever found – do we think it’s a manufacturing defect or by design??

Jerry999 said:

Very interesting....
I just stumbled across this post.
My daughter’s car is exactly the same (a 2011 Ford Ka actually).
It’s been running rough and I was trying to fix it.
I also found this as well – no hole in the plastic.
However, I thought it was blocked and eventually manage to make a hole.
Now I’m wondering if I should block it again…
As tashman says what’s the point of fitting a hose that eventually splits if it leads nowhere (and has a little tee piece that often snaps off!).
Was an explanation ever found – do we think it’s a manufacturing defect or by design??

Click to expand...

Ours broke but i managed to repair it, note whilst the hose was split it didn't effect the running , new plugs try(Iridium) and consider Lambda?