Help with Aircon problem please

[dannyfiveforty]

good evening all,

I have a problem with my Aircon and don’t know what route to go next.

Car (2008 CL63) had ‘aircon off’ permanently lit and fault code of low refridgerant pressure.

I have increased the pressure by adding gas using stp refill kit. Pressure is up to 30psi (on the low pressure side) I have now removed the fault code and the car now recognises the gas pressure is there and it is letting me now have ‘aircon on’. After a 10 mile drive the aircon is still blowing warm air, and I have gained a hissing noise that sounds like it is just behind the centre console vents. I have checked for further codes and nothing except for ‘94DD m16/33 left B pillar air distribution actuator motor communication error’ this confused me as my car doesn’t even have b pillars.. anyway, that aside, as I don’t believe that would cause aircon to blow warm.

Using my live data machine with the engine running I have engaged and disengaged the compressor several times whilst listening to it, it has a tiny jolt and belt noise variation as it loads up when coming on and off, plus it’s giving no codes. So I believe that’s running as it should. Finally after 24 hours I have re checked the aircon pressure and it’s holding exactly the same pressure as I put in.

So what’s going on?

Thanks

 

[star]

I think you need to empty the system and put the correct weight of gas in, going on pressure is just guessing.

 

[dannyfiveforty]

ah ok, I think I follow, there’s no direct relationship between pressure and the weight in there? It could be that pressure is reading high (30psi) but there’s not enough in? Obviously if this is the case I need to get an aircon specialist to look at it now as like you say it would be guess work.

 

[curious]

It wouldn't hurt to get it pressure tested before refilling by weight. It's much cheaper than wasting a refill.

My aircon kept needing to be refilled every other year until I got it pressure tested. A very small hole in the condenser became a larger hole and obvious to locate. Changed the condenser, pressure tested, refilled and everything has been good for 5 years now.
I also keep the aircon 'on' all year round to prevent non-use causing problems.

 

[rifiki]

I can't help you with your problem, aircon usually goes wrong through lack use. When fixed i keep it on most of the time.

 

[dannyfiveforty]

It wouldn't hurt to get it pressure tested before refilling by weight. It's much cheaper than wasting a refill.

My aircon kept needing to be refilled every other year until I got it pressure tested. A very small hole in the condenser became a larger hole and obvious to locate. Changed the condenser, pressure tested, refilled and everything has been good for 5 years now.
I also keep the aircon 'on' all year round to prevent non-use causing problems.

Its pressure testing good, and holding. but I don’t know what weight is in there.

 

[star]

It’s not pressure testing you require, the system has pressure. If a test were to be carried out, it would be a vac test and hold. If and I say if you have a leak it’s very small, the adding of a dye on refill would help find it. Or it maybe just down to natural losses.

 

[dannyfiveforty]

I have a mobile aircon guy coming out to it next week. Cheers guys

 

[Uncle Benz]

Getting someone with the gear is the best answer. My general rule of thumb is the high side will be three times the low side if the compressor is healthy. Those numbers want to be in the region of 150/50, so 30, if measured on the low pressure side of the system is too low. The gas volume is too low, high enough for the system to run, but not high enough to provide decent cooling. The asthmatic gnat hissing away behind the dash is the second clue. Low gas volume will make a hissing sound at the orifice jet before the evaporator. You'll hear this as a hissing sound behind the dash. The system will work, and on a cooler day it will feel like it's working quite well. Bring on a baking hot day, like today though, and it'll quickly be overwhelmed and the air from the vents will feel ambient at best. A complete vacuum of the system and adding gas by weight is the best, and only way to do it in my opinion.