Air deflating sound when parked?! Help appreciated

When i park my truck after a couple of hours of driving, i heard a weird air deflating sound coming out of the front end of the truck and the sound lasting for 1 second and repeating each 20 seconds
The sound is like when you are deflating you tire but you just allow air to go out for 1 sec
Does anyone know what the problem could be ?
Thanks a lot
And by the way, the grease went out of both by cv boots, i guess the rubber was dead, i changed both rubber boots, and the sound remaind.

 

I remember reading about your hissing noise problem from another member who posed the same issue.

IIRC the consensus was that it is totally normal and fine, and that a lot of other members experience the same thing.

This is not the thread I remember reading but it seems to touched upon the same thing and responses:

http://www.tacomaworld.com/forum/1s...g-sound-air-intake-when-engine-shuts-off.html

 

water dripping on your hot exhaust?

 

Thanks for the link madjik man
Konaborne i have the air conditioning on, most of the time these days and notice the water dripping when parked, that could be the cause of the sound will have to check

 

Condensed water from air conditioner system can drip onto anything that is hot and hiss. Happens on all three of the vehicles within mi familia

 

You should be able to pop the hood or crawl underneath when its making that sound, and figure out exactly where its coming from. We can't do that for you.

 

I noticed it to. Goes on and off when i turn my ac on and off. Ac is working fine in our 32c weather, by the way

 

positive it's your condenser unit dripping onto the exhaust. I had the same problem. I just hooked a drain hose on it and routed it down to drain next to the tire. hissing problem solved for me atleast

 

I think it's the evap I think it's called. Try unscrewing the gas cap off and see if that makes it go away. I know there's a link about in here somewhere. I just can't really look too much cause I'm on my phone