clk320 - recharge a/c ?

[98farmer]

hello,

i'm new to the board but glad i found this place!

question, i need to recharge my a/c. i bought a can of R-134a trying to save myself $80 service charge but am in need of a little help.

directions say to connect at the a/c low side service port. i think i found it but im not sure and dont want to waste the can nor harm my car.

can anyone please point out where the low side service port is? have looked for a diagram online but have not found one show this area of need.

Thank you!

 

[Glenn Smith]

I'm not sure exactly where it is on this model and the autodata cd doesn't show either, but it will be between the compressor and the evaporator (the bit in the dash) either in the hose or on the compressor itself. you willnot be able to fit the charging hose on the wrong side as it will not fit the high side, typically on the Mercedes the high side is on the condensor.

 

[star]

Hold on, do you know how much gas u have in the system? before you put some in. If u drain the system how will u vac the system out? too much gas or too litlle gas and it wont work efficiently. sorry but i Think you have wasted ur money.

 

[98farmer]

im pretty sure i sound both the high and low side. the is a port in front of the raditor just behind the grill after you open the hood. i tried this port but it wouldn't fit. then i located what i think is the low side port, just above the front driver side tire. i haven't tried the connection but it is smaller than the one i described being in the front. would there be more than two ports that like this on the car? or are there just two 1.high and 1.low?

thanks for the help and any other advise you may have!

 

[98farmer]

Hold on, do you know how much gas u have in the system? before you put some in. If u drain the system how will u vac the system out? sorry but i Think you have wasted ur money.

no, i have no clue. i just know it isn't blow cold at all, maybe in the mid 70 range. i was at autozone picking up a few things and saw this for $16.00 and was going to try it.

i wasn't planning on draining the system. the can has a quick connect hose on it and thats where i was going to start.

i found a website lastnight that told me how to get the sensor reading and has a place to plug the info in. after i plugged the info i it came back saying that it appears that the refrigerant is low. told me to add some first and try it out. if stays cold problem fixed, if not, could be a leak.

thanks for your concern and im willing to listen.

 

[Andy Wr]

It will only fit on one port, 2 ports of different sizes are fitted on R134a cars, but as already said, dont do it! If you must do it, drain the system in an environmenttally friendly manner and in line with your own local regulations (EPA in the USA from memory), dehydrate the system using a good vac pump with torr gauge fitted and then, only then weigh in the exact charge, if you dont as I have said before, light the blue touch paper, stand well back and put your fingers in your ears.

 

[Glenn Smith]

It will only fit on one port, 2 ports of different sizes are fitted on R134a cars, but as already said, dont do it! If you must do it, drain the system in an environmenttally friendly manner and in line with your own local regulations (EPA in the USA from memory), dehydrate the system using a good vac pump with torr gauge fitted and then, only then weigh in the exact charge, if you dont as I have said before, light the blue touch paper, stand well back and put your fingers in your ears.

I don't generally agree with just topping the system up, but if you follow the instructions it can be done safely and satisfactorly, these systems usually draw the gas in on the low side, but if the level is really low you will either have to let some liquid in first or trick the system into thinking it has gas in so the compressor will run (either short the switch wires, although this won't work if it is a pressure transducer rather than a switch) or put a live feed straigt on the compressor wire. you can let the system run untill you feel it is working ok, check for bubbles in the sight glass, add a little more if there is, but to be honest if you have no gas left you have a leak and this needs sorting out (possibly condensor leaking) the top ups are really only meant for yearly topping up of systems in good working order (typically you will lose around 10% of the charge a year even without leaks).Most systems i recover from only have around half a charge left.

 

[98farmer]

well, since there is such a conflict of ideas here. this is what im gonna do. take the can back and get my $16.00 and use that towards the $102. it will cost me to have a tech do it.

thanks for all the input and suggestion.

 

[Andy Wr]

I don't generally agree with just topping the system up, but if you follow the instructions it can be done safely and satisfactorly, these systems usually draw the gas in on the low side, but if the level is really low you will either have to let some liquid in first or trick the system into thinking it has gas in so the compressor will run (either short the switch wires, although this won't work if it is a pressure transducer rather than a switch) or put a live feed straigt on the compressor wire. you can let the system run untill you feel it is working ok, check for bubbles in the sight glass, add a little more if there is, but to be honest if you have no gas left you have a leak and this needs sorting out (possibly condensor leaking) the top ups are really only meant for yearly topping up of systems in good working order (typically you will lose around 10% of the charge a year even without leaks).Most systems i recover from only have around half a charge left.

Thanks for that, if you do just "top up" be careful not to invert the can and pour liquid refrigerant in the compressor, even with the access valve in the suction line this pipe is the suction side so will draw the liquid in the compressor before it has chance to boil off, even if it has a suction line accumulator you can still get liquid overload and this will smash the reeds and also worth noting is whilst trying to clear the bubbles from the sight glass make sure that the engine is running at 2,000 rpm, and if you have a partial restriction in the filter drier, orifice tube or even a partially closed down expansion valve due to a worn power element this can also give an impression of been short of gas so no amount of gas will cure this just overload the compressor to a point of self destruct.

If in doubt it is always wise to weigh in the exact fresh charge, if it still appears to be under performing at least you can rule out the gas charge then, sometimes people create more problems, keep it simple guys.