Air con problems
 

Hi all,
I've never had any aircon problems with any other cars, (probably because i like to have the windows down rather than the a/c on) but on my bug, every time i switch it on (the A/C)..a very annoying rattle comes from the engine, you can even feel a bit of vibration on the pedals..i cant really trace it, it also dramatically sucks all the power out of the car and really drags the car down..on really hot days it becomes worse... has any one here ever had the same problem/ or similar symptoms...

cheers

a/c draws 10 to 15 kw from the engine.

its draining alot more than that...what about the rattle/ vibration ?

On hot days the car will make less power (hot compressed air makes less power) anyway.....Running the A/c will have the under bonnet temps over 65 degrees on hot days.

What mods do you have?????

Pod under the bonnet?

yea, i know the under bonnet temps will typically result in lower power out put on any engine, but its the rattle and the vibrations that really bother me, sounds like something is loose (or becoming loose)....its quite annoying as the car runs like new when the a/c is off..

the mods are pretty basic, Pod filter, and turbo back 3" exhaust..(used to have an electronic boost control, but that was disconnected by the guys at subaru when the engine blew one piston, which they replaced, and and new short block as well )...

would these mods affect how the a/c functions?..

[QUOTE=blurex;429026]

the mods are pretty basic, Pod filter...
would these mods affect how the a/c functions?..[/QUOTE]


That is your main problem right there, pod filter sucking hot air constantly, and even worse in summer.

Pod will KILL the power on a hot day.... A/c adds heat load to the engine bay.

Plus a pod with a stock ecu is asking for AFR leaning issues / flat spots.

So YES, running around with the A/c cranked on a 38 degree day, when you engine is being asked to make power from air being drawn through the pod under the bonnet (where the air temp is approaching 70 degrees celcius), will make it feel doughy and unresponsive/ lack power / idle lopy / idle low / surge etc.

Get rid of the pod and buy a process west cold air intake (goes inside drivers side front guard).

Get a tune.

Reckon it will be the aircon compressor giving way. Either because the aircon oil in the compressor is low or that the belt on it is worn and due for a change.

Also do check your air con clutch is not wobbling when the air con is turned on. That might be the cause of the rattling sound

From what you have said, sounds like as said above the aircon compressor is starting to seize. if you bring the revs to about 3000 and turn the ac on and off do the revs drop dramatically? eg more than about 300rpm? if they do then chances are the comp is getting tight.

also i cant see a 4pk belt being able to transfer 10-15kw. no offence ross mate, but that would be a seriously inefficient aircon system. 15kw will cool a large house :)