head gasket failure.
Stuck open thermostat.
Restricted coolant flow (plugged heater core).
Temp blend door malfunction.
Low on coolant.
blowing through a straw,air touches the walls of the straw and makes the it vibrate and as it is a light body it makessound
Free blowing means that the trumpet doesn't feel stuffy when you play it. I'm not really sure how to explain it, other than comparing this: imagine blowing air through a soda straw, then blowing air through a water hose. The water hose is bigger and will allow you to blow larger amounts of air through it.
you have a vac. leake or the oneway check valve is not working.....
The wind you create by blowing through it whistles through the holes in different ways depending on the ones you cover. The holes create the sounds - otherwise it would be similar to blowing through a straw.
Draft
blowing through a reed
a draft
draft
by blowing through the mouth peice
There are machines you can buy for blowing up balloons; check with a local party store.
If central air conditioner turns on but is not blowing through the vents, check the filter. If it is dirty, change it. Change the thermostat into cool, this will defrost the air conditioner.
Most likely is one plug malfunctioning or a dirty injector.