Automotive Air Conditioning Information Forum

hello every one i appreciate if somebody can help me .

i have a civic 99 i keep the car in a good condition , 2 months ago the ac system starts to work hotter , the problem was the condenser was hot around 80 c and the compressor safety valve did blow all the gas out with oil in a white kind of smoke , so since the shop was a honda shop and anther 2 cars one ek9 and anther sedan had the same problem i installed the biggest condenser that fits inside i think 120x80cm (the original one is tiny) , replaced the receiver drier , expansion valve , pressure switch ,cabin filter . all hoses flushed and seals replaced . and inside unit cleaned and evaporate flushed and cleaned with coil cleaner .

i disconnect the heater core hoses because the civic system doesnt close properly.

fans, i replaced the honda fan with 3 fans x 120 watt universal fans, 2 infront and 1 in the back so i dont think air flow is an issue . with the radiator fan kicks in total 4 fans are working.

and the freon is dupont r134a and compressor oil replaced.

so basically everything is new except the compressor

now the problem is the condenser is still hot real hot compared to other cars .

the ac get cold only when the car is moving and not as much as it should be .

the glass eye show fluid inside , i decreased the pressure to 40 psi in the low side and raised the idle to 1500 rpm in order to get some cold air because most of my driving is inside the city .

when the rpm raise to 3500 the pressure in low side drops to 20 psi and the compressor stop and pressure becomes 60 psi then drop again to 40psi when compressor kicks in .

i get around 20 degree temperature deference between outside and inside the car.

increasing the cold side pressure to 45-50 psi i get colder air if iam in the high way but none at idle.

i did a lot of searching but the only thing i found that the compressor outlet valve might be faulty.
my 2 concerns is that i want a cold ac and iam afraid that the hot compressor will cause a sludge inside the system will make me change parts again .

any advice is appreciated.

also where a live its legal for me to work with refrigerant.

plus the condenser is singular flow type, for me i thought the single flow alow the gas to get colder than a multi flow condinser

Did you add the R134a with a scale to insure the proper amount? What is the high side PSI? A multiflow condenser is better than single flow.

well i cant read the high side because when we made anew pipe for the hot side so it can fit with condenser the hose shop didn't put the gauge fitting and i only notice it when it was too late , as for the scale it was a trail and error way i cannot use the manual because the condenser is bigger . so basically its add add then little remove then little add .

if its necessary please advice ho to put a high side gauge fitting without major work & parts

i got the single flow because the parts shop guy said the the larger pipe diameter is better than a multiflow when it come to tolerance for debris .

anther thing the fans are the Chinese universal type slim fans without the shroud but i did put a foam type gasket between the fans and the condenser but i believe that the 3 fans are giving enough air flow .

iam sorry that i write alot but iam tiring to describe as much as i can

i have some temp data i hope its helpful its all in degree Celsius , outside temp 42 degree and humidity is high the car in full shade. inside temp when drawing air from outside 27 degree and the door is opened . condenser temp 70 degree ,low pressure line temp 35 degree .
air coming outside the condenser is 70 degree ,and the added trany oil cooler behind the condenser temp is also 70 degree.
the cooler is pipe and fin type as the pic below.

the car had the radiator and condenser side by side with each separate fans , now the condenser is in front and the right side the radiator and left side the tranny oil cooler with a space of 1cm using a rubber spacer like the pic below

Tube and fin condensers are not good. The parallel flow is much better, the result of years of engineering effort on the best way to condense R-134a. Since R-134a is harder to condense than R-12, car makers quit using tube and fins when R-12 was banned. You may have trouble with the vacuum pump getting the air out before charging without a high side fitting. Really if it were my car I'd put it back to stock and fix the fan issue that caused the initial problem. Generic Chinese fans may draw lots of watts but move little air. No system reaches full performance at idle, but a worn scroll compressor can really lose compression at idle speeds. You have to be careful with the oil amount. Too much oil will reduce performance. Also like Dougflas said, charging by weight is essential.

20 psi suction proves that discharge valve and scroll tangential gas bypass are ok.
Scroll mounted thermal protection switch (TPS) may disengage clutch at low suction/high discharge or air in system
Excessive oil just raises louver temp with scroll application
Normal scroll wear turns oil gray but doesn't cause condenser restriction. It may prevent txv complete closure but that is not your problem.
With high fans power draw the idle clutch voltage may aproach borderline an should not drop below 11.5 volts at high under hood temp
Hope this helps,
hotroac

thanks alot guys this is the difference between people who know and people who pretended to know to make a living . until recently AC was black magic to me .

i had to learn because the new business model is trail and error with the customer money and time at least where i live , i dont have anything against workshops i re-manufacture injectors for a living thats how i can acquire all the stuff on whole sale price. but really non of the shops i went to did use a scale , or even check the high side .for them engine off 80 psi low side engine on 40 psi low side pressure ,pipe is cool ok your clear to go.


i even suspect the oil amount is high as the guy poured around 300ml which is around 10 oz of pag oil .


the original civic condenser is small and single flow which started the problem in the first place.

as for now is there a way to calculate the amount of oil and gas for a non standard system. because i have anther car which is a Mitsubishi colt 99 with black death which i want to use a crown vic compressor (got new one very cheap & the mitsubihi units not that good ).

well i can remove 2 off Chinese fans and return the stock ac fan and i can vacuum the system and put i high side valve then fill it again put i want to know what is the max safe compressor temperature in general and how to know the proper amount of freon and oil to put in the system


Thanks again

total oil in Civic txv system should be approx. 4.5 oz (135cc or ml)
hotrodac

and freon?