Cold start up and engine shut-down

Greetings - new 2015 4x4 6 cylinder; noticing on cold start up only, two minor machine like sounds at appx the 30 second point, then no further noise. On engine shut-down, hear longer noise with what sounds like air escaping. These noises come from the passenger side engine compartment. I spoke to a few dealers and followed some threads, and indications are this might be a pump of some sort and is normal. Anyone experience this, both on cold start and at shutdown? Thanks for any info.

 

2013 prerunner, on shutdown makes the machine noise but have been told it is normal, haven't talked to dealer about it yet though

 

Thanks very much.

 

The shut down noise a normal.

Also welcome!

 

Thanks.

 

Possibly an EGR pump? Something to do with the emissions controls?

 

Some mentioned evaporator, others a smog pump - supposedly pressurizes on start up, and releases when shut down.

 

Probably the good ole Secondary Air Injection Pump - totally normal. Pray that it fails when you're still under warranty or be prepared to shell out $1100. Mine died at 53k miles and sent the truck into limp mode.

 

Thanks very much.