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!