Crallscars

Do vacuum pumps go bad?

I drove my truck into work today, and I could hear a different noise from under the hood at about 1200 RPM to 1400 RPM, I don't think it's always been there and drowned out by the radio, I doubt its a resonance in the exhaust, it's not the AC I turned it off, if it's the power steering it's a different noise than normal.
The VP44 is a Blue Chip and about a year old. Otherwise the truck runs fine

Any guesses or ideas on how to isolate and figure out what it is?

I have about 240,000 miles on the truck

patdaly

Yes they wear out, put a vacuum gauge on the T up by the cowl and see what she is pulling.

Crallscars

My Vacuum accessories seem to be working, what is the range of Vacuum should I see on a gauge?

Is there any maintenance I should be/have been doing to the Vacuum pump?

patdaly

No maintenance required, I have never stuck a gauge on mine, but I would guess that 25" or more should be plenty.

KATOOM

If you're hearing strange noises under the hood then use a mechanics scope to identify where its coming from. Or.....just get a slim solid piece of wood like a dowel or small broom handle. Place one hand over the end of the wood piece so your ear is resting against the end of your fist. Then touch the other end of the piece of wood on various components under the hood. The isolated noise will transmit through the wood into your ear and you can pinpoint whats making the noise.
Other than that, vacuum pumps are rebuildable and vacuum should be no less than 25 per the FSM.