Gerb

I was watching someone park my car and i heard the engine make a vacuum like noise. Anyone know what it is. It lasts for like 5 seconds only. We got a mechanic to check the car before we bought it 1k km ago a month

IS350AWD

Sounds like the A/C compressor turning on to keep the engine cool. If so, then that's normal.

NYKnick101

Does the car have an intake? that is the only vacuum noise loud enough to hear from outside the car other than the a/c compressor.

DKIS350

Many cars have air injection pumps that kick in on cold starts for a few seconds (all for emissions). I dont actually know if the IS models are equipped with this (im sure someone can confirm this here) but i think the GX, and most of the 4.7/5.7 Toyota V8s had the injection pumps. They commonly failed on the Tundras.

Gerb

Nope no intake, Probably a/c compressor. Its really on and off normally on starts or when u turn it off.

Gville350

iTrader: (10)

If it is truly a vacuum leak, a truly impressive and easy-to-do DIY fix is to get yourself a fog machine and let the fog loose in the engine bay. See where the fog is sucked up into the motor anywhere else other than the air filter.

GL!

Joelseff

has the car been idling for awhile? It might be the fan.

Sceanzo

EVAP system.