hissing after a drive...?

[joko]

noticed last few times of using car a hissing coming from the engine area when i turn off...can only hear it from outside the car when just switched off..sounds like steam or air or something...

i opened the bonnet earlier (before driving) and notticed that the cap for the windscreen fluid was open...could it be that?

i assume that it gets mildly warm, but not steaming - but am i wrong?

i havent dont any other checks yet, i will next time i drive anywhere.

if not that, any other ideas?

its a passat, tdi tiptronic, auto, estate, diesel, 2002.

thanks

[Buenchico]

Have you checked your coolant level recently?

If you've got a tiny hole in a hose, you could have coolant hissing out all of the time that you're driving (but not notice because the sound is masked by engine noise). It will then continue hissing out until the pressure in your cooling system drops.

Alternatively, try taking the snakes out of your engine compartment ;-)

Chris

[LCDMAN]

It's your aircon "venting" any moisture.

[Buenchico]

While I'd still recommend checking your coolant level, LCDMAN has offered a valid alternative solution there. (I never use the air con in my car; it clobbers the fuel economy rather too much for my liking!).

[AlBags]

Hot engine = Coolant expands
Cool Engine = Coolant contracts ... and draws cool air back in.
On many engines, you can hear this.
Certainly not washer resevoir.

Either this or the aircon.

[SpikeyBush]

Check your hoses to be on the safe side.

While I agree with Buenchico on the aircon hammering economy, I have to use it when visiting customers this time of year. I can't do my sales pitch with smelly 'pits and a soggy shirt