strange noise coming from engine

[lmholmes11]

The other day I noticed there was a sound coming from around the drivers side front wheel well. It sounded like spurts of air? My first guess is the belt needs replacing. I'm just curious if anyone has ideas since I can't really pin point wherre exactly it is coming from. Also, it only makes this noise when cold. After warmed up it no longer makes this noise...

Thanks guys

[DmaxMaverick]

It could be any number of things. If the belt has about 100K miles or more on it, just replace and stash the old one somewhere in the truck. If it has less than 80K on it and looks good, wash it and the pulley surfaces (warm soap water, rinse/dry well). While the belt is off, start the engine and listen for the same noise, under the condition it would normally be present. If still present, try to locate the to source, use a stethoscope if necessary. If the noise isn't there with the belt removed, check each pulley and accessory for free rotation with no bearing noise, and inspect the pulley/belt surfaces for inconsistencies. If the idler(s) and/or tensioner have about 100K miles or more, just replace (and stash them in the truck, as well).

A little noise from the PS pump is normal when cold. Sometimes, a fluid flush/fill will help. Easy process if you remove the return line from the hydroboost and extend a hose to a container. Idle until empty, and refill. Repeat until all the fluid is clean and replaced. I use synthetic ATF, but GM recommends specific PS fluid, and synthetic is available for that, as well (at 4-8 X the cost of syn. ATF).

If the sound is a "ticking" noise, that sounds like random key strikes on a manual typewriter, well....That's another issue. Several things can cause that, including oil brand/grade, usually for a period after a fresh change. If this is happening, don't sweat it. It is harmless, and nothing more than an annoyance.