My mac pro is making wierd chirping noise

You could install smcFanControl 2.6 (https://www.eidac.de/?p=312). It's free (donations welcome) and if changing the speed of the fan produces a change in the frequency of the chirping noise, then it's very likely it's the fan.

smcFanControl is a useful utility; my 8-core MacPro shows CPU temperatures very high when doing long video conversions with Handbrake, and ramping up the fans somewhat - just for the duration of the conversions - keeps my CPU temperatures down to a better level.

I have no connection with the software or its author other than as a satisfied user.

More likely the fan.

Bearing is worn or it is rubbing against something.

If it was your hard drive it would be dead.

Put your ear to it and see if you can locate the source of the noise. The fan is near the upper middle from memory.

The drive is lower right.

Peter

Noises cause by fans are most likely to repeat one the order of once per second, as something hits the fan once every revolution.

Noises that come from your Mac once every few minutes are likely to be coming from the speaker. They are more likely to be unexpected alerts from programs, not physical problems.

Noises from crashed Hard Drives can be screeching similar to the noise of the trolley going around the tightest bend in the underground subway system, near Arlington Street in Boston.

That cricket has finally been hacked to heath by the fan! 😟

Peter

It could be: it could also be related to a fan. Anything which rotates can produce odd noises if the bearings are dry or getting worn. Exactly what Mac (model and year) is it which is suffering from this? Your question says Mac Pro but your ID says MacBook Pro:- the two are very different.