Can vacuum hoses be too small?

Hi, I have an 89 Ford Aerostar, and recently I replaced all my vacuum
hoses. The auto parts store didn't have the exact same size as my old
hoses, but the kid working there told me I could use smaller hoses. I
said fine and bought the six feet I needed.

Later on, I read in my Haynes manual that vacuum hoses are color coded
and have different heat and collapse tolerances, so you should get the
exact same kind.

How important is this? Is this a case of the Haynes manual being a
Charlie-boy again, or should I redo my vacuum hoses?

The van runs, but since I changed the vacuum hoses in the first place
trying to get rid of a vexing intermittent problem, I'd like to
completely rule them out as being potentially problematic.

Thanks!

The new vacuum hoses will work at least for a short while. Over longer time a vacuum hose can become brittle and crack, or become soft and collapse. For most applications size is not critical, but for some things e.g. vacuum advance or brake vacuum boost the proper size should be used.

wrote:
>
> Hi, I have an 89 Ford Aerostar, and recently I replaced all my vacuum
> hoses. The auto parts store didn't have the exact same size as my old
> hoses, but the kid working there told me I could use smaller hoses. I
> said fine and bought the six feet I needed.
>
> Later on, I read in my Haynes manual that vacuum hoses are color coded
> and have different heat and collapse tolerances, so you should get the
> exact same kind.
>
> How important is this? Is this a case of the Haynes manual being a
> Charlie-boy again, or should I redo my vacuum hoses?
>
> The van runs, but since I changed the vacuum hoses in the first place
> trying to get rid of a vexing intermittent problem, I'd like to
> completely rule them out as being potentially problematic.
>
> Thanks!

--
Mike Walsh
West Palm Beach, Florida, U.S.A.

Thanks for the info! I'll change 'em again in a year or so, I guess.
I'm going to change the one that goes to the heater/AC fan now though
because ever since I changed it, the van makes a bumping sound near the
fan when I turn on the AC. Didn't do that before! What do you think
this is? Is it the vent door opening too quickly?

The noise is probably from the door moving faster. It might have been slower with the old hoses because of leaks or restrictions.

wrote:
>
> Thanks for the info! I'll change 'em again in a year or so, I guess.
> I'm going to change the one that goes to the heater/AC fan now though
> because ever since I changed it, the van makes a bumping sound near the
> fan when I turn on the AC. Didn't do that before! What do you think
> this is? Is it the vent door opening too quickly?

--
Mike Walsh
West Palm Beach, Florida, U.S.A.