Heating control - is it fubar'd? and air-con question

[DickBarton]

I think my heating system has FUBAR'd itself...I don't really drive with it turned up much about 20 - although a few times of late it has been at 23...anyway it's ok for a bit, then all of a sudden it'll go very cold then a few minutes later it'll be belching out heat like it is going out of fashion.

I don't switch the flow from window and feet (mainly as the driver central vent doesn't work) and generally the airflow is outside into the car rather than recirculation.

If I switch my aircon on, I get a smell - sort of like it's never been used - I don't run it much but will run it when the car is needing re-fueled just so it gets used. I saw Halfords were doing a air con refresher that you could use to clean the smell from air con units - you switched the engine on, stuck the airflow on recirculate, switched on air con, opened this can and stuck it in the rear passenger footwell and shut the doors for 10 minutes...it got the air and this potion circulated and removed the smells and stuff - anyone tried it and is it effective?

I made sure the pipe was re-attached to the back of the temperature control dial when I reinstalled the central console so I don't think that is affecting anything but the aircon doesn't really feel cool when the temp is set at 17...

Any advice appreciated (unless it is to go get the air con recharged as that'll cost about £150!)

Cheers.

[Nick Mann]

An air con re-charge should be less than half of that.

The air should blow quite cold when set at 17, so it sounds like it does need recharging. The smell remover thing I have never used so can't comment.

My heating goes cold after a long period of driving with the lights on. I think that the controller gets warm from its own internal lighting and so it starts to blow cold. It only happens on journeys of over an hour with the lights on. When it does it, the heating does not suddenly get warmer afterwards.

[AderC]

I've tried one of those air-con cleaner thingies and it worked for me. Prior to this I'd used Dettol antibacterial air-freshener (put a/c on full blast and recirc, give it a good spray and shut the door for a few mins) but this is a more temporary fix.

aDe

[Davezj]

there are other air con threads out there which explain in good detail how to recharge the air con, but i will add if you over pressurise the system. when you run the air con the pump will click in and out at a very quick rate. every 1-2 sec. if this does happen you can release some pressure by pushing the ball valve that you filled the system with. only do the with low pressure side of system for obvious reasons, the high pressure side should never to massed with.

i have used dettol and millton fluid, to clean the air con and it does work.

[Nick VR4]

A recharge is around £25 - £35 from a garage round here not £150

[DickBarton]

Hmmm, will check the prices again for the recharge...mate got it done a few months ago and complained that it cost him £150...might be due to it being an Audi though!

Thanks for the advice...still unsure why my heating varies so much though...I ended up having to stop to put a jacket on this morning it was blowing such cold air (temp said 25 as well!) - then 5 miles down the road it started wafted warm air out the vents...I suspect the hamsters may be needing fed!!!

[psbarham]

if its blowing hot and cold, just check the coolant level, also does the engine run hot/cold at all. its possible the coolants a bit low and has airlocked the heater matrix. also whats the antifreeze content like? is the coolant blue or a rusty poo colour?

[DickBarton]

Engine temperature on the dash doesn't fluctuate...will check levels later...if there is an airlock - how do I get rid of it?

[psbarham]

Engine temperature on the dash doesn't fluctuate...will check levels later...if there is an airlock - how do I get rid of it?
i belive there is a couple of bleed screws on the system, can't rember where though. have you tested the antifreeze content yet? if you can't find the screws theres a couple of tricks you can do,with the engine warm , gently remove the rad cap then pump the bottom hose to force the air to the highest point, hopefully the rad, or what we used to do on cossie's was to remove the expansion tank cap then start the car and let it heat up until it starts spitting steam out of the cap. once it stops spitting turn the engine off and let it cool down, then top up the cooling system with 50% antifreeze mix. these are not the perfect way to do it and personally i would find the bleed screws

[Rambaud]

Hmmm, will check the prices again for the recharge...mate got it done a few months ago and complained that it cost him £150...might be due to it being an Audi though!

Thanks for the advice...still unsure why my heating varies so much though...I ended up having to stop to put a jacket on this morning it was blowing such cold air (temp said 25 as well!) - then 5 miles down the road it started wafted warm air out the vents...I suspect the hamsters may be needing fed!!!

Depends how old his Audi is.

I used to pay over £80.00 about 10 years ago as it used the old type of gas. :(

[DickBarton]

Just checked my fluid levels and they are all ok...anything else I can check that doesn't involve stripping the car down? (it is dark, cold and wet just now!!!)

[Paul Beazer]

When the temp fluctuates do you have the air con on or not?

The reason i ask is the climate control seems to work better when the aircon is on. When its just the climate control it seems to blow cold and then hot on mine too. Not too bad, obviously the sensor isnt too sensitive, so it varies the temp on the air coming in depending on the temp in the cabin, but prob only after there is a couple of degrees change in the internal temp.
It doesnt seem to vary as much when the aircon is on.

BTW If you overfill the aircon, it jumps about as the high pressure switch kicks in. I did this and cured it by letting some gas out of the high pressure valve, just cover it with a rag first otherwise it sprays a bit! Cured it in no time.

Oh and Kwik fit do aircon servicing at most branches for £45 currently.

[Davezj]

When the temp fluctuates do you have the air con on or not?

The reason i ask is the climate control seems to work better when the aircon is on. When its just the climate control it seems to blow cold and then hot on mine too. Not too bad, obviously the sensor isnt too sensitive, so it varies the temp on the air coming in depending on the temp in the cabin, but prob only after there is a couple of degrees change in the internal temp.
It doesnt seem to vary as much when the aircon is on.

BTW If you overfill the aircon, it jumps about as the high pressure switch kicks in. I did this and cured it by letting some gas out of the high pressure valve, just cover it with a rag first otherwise it sprays a bit! Cured it in no time.

Oh and Kwik fit do aircon servicing at most branches for £45 currently.

are you sure it was the high pressure side and not the side you filled it on (low pressure)?

i was always told never to mess with the high pressure side.

[DickBarton]

Hi Paul,

No air con is hardly on...glad to hear it isn't just me that experiences this...I didn't think it was climate control, but that would certainly make sense...when it is cold the cabin temp has clearly dropped so it would warm up to make an affect...when the cabin temp heats up more than required then the cold air obviously gets pumped in.

A very daft question but does a N reg manual VR4 have climate control and is it on by default?

[Nick Mann]

You will have climate control. Climate control is air conditioning, run by a computer. So you dial in the temperature you want, press the temperature control knob, and the system goes into AUTO mode, doing what it thinks needs doing to achieve the cabin temperature of your setting.

[DickBarton]

I don't switch it on...might start that and see if it makes any odds...

[Paul Beazer]

are you sure it was the high pressure side and not the side you filled it on (low pressure)?

i was always told never to mess with the high pressure side.
Yes deffo, i like to live dangerously!