AC recharge.. A sucess!

[elwesso]

So today I had my AC recharged. For some that have already known, my evap was icing over a little and it wasnt as cold as it should be... They evacuated 1.7lbs, but they said that a couple ounces stays in thelines, so more like 1.5lbs was taken out, regardless of the semantics they said it wsa probably a tiny bit low...

Pulled it on the vacuum for 1 hour as requested... Their machine would only let them do 30 mins at a time, so they just let it run twice...

As per the FSM, you are supposed to short the ambient temp sensor, so that the compressor stays at max stroke.... But whatever the case is, they measured the vent temperature... At the time it was probably 80F with 60% relative humidity and they said it blew 38F air on medium speed... Pretty impressive I say.. I drove it home but it was raining and it seems to be good, i wouldnt say at lower speeds it seems colder but that doesnt surprise me...

[maxnix]

Great news.

Did you change the dryer also, or just go with a R134a and lubricant recharge?

[elwesso]

i didnt change the drier.. The system was never opened, so I didnt really see the use...

I think what im going to do now is try and tweak it from here... See if theres any way to adjust the compressor or expansoin valve.. It was really humid today, but not very warm, so we'll see... I need to drive it on the highway before I make any decisions..... I dont see how I could get any better than 38F as hot as it was before it rained today...

[maxnix]

i didnt change the drier.. The system was never opened, so I didnt really see the use...

Well the drier acts like a filter, catching impurities and moisture, so it is always a good idea to replace it after a few years as suggested by Q45tech's AC flushing routine.

No adjustment for expansion valve (fixed orifice) nor continuously variable displacement compressor, other than clutch pulley size, which would probably not be a good idea.

38°F if pretty good, but there might be a little more drop. Really all depends how much air is flowing by the condenser when the system is up to snuff.

[Jeff Williams]

Wes, if the system has not been opened, don't open it to replace the dryer. The impurities it catches is from burned out compressors. There is no other impurities in the system, unless it is pumped in with the new refrigerant.

There is really no adjustment that can be done on the expansion device or the compressor that I would recommend.

The best thing you can do, is clean the evaporator coil and make sure there is no abstructions in the system.

The optimal RPM for the compressor is 2500. If it gets a little hot in the car, just put it in neutral, and rev the motor to 2500. The air should get nice and cool.

Low refrigerant causes low temperatures and freezing up of the accumulator and evaporator coil. That is why it seems to work great for a while, then gets warmer. When you stop, condensate pours out of the drain. If you open the hood, the accumulator and lines would be covered with ice.

Usually an evacuation and re-charge is all that is needed.

I am glad you got her back working.

Be sure, to turn OFF the A/C and defrost before you make those WOT runs. It is hell on the compressor.

[elwesso]

Well remember that the AC compresor shuts off at i think 5000 RPM... Id have to ask robert for sure...

I agree with you about the drier, which is why I didnt replace it... Before I do anything else I have to get a manifold gauge set and check the pressures, and then ill consider doing a flush, however I probably wont spend a ton of money on it because the AC is already colder than most Qs.....

[93 Q45]

hope you got all the oil out otherwise your in big troublei use compressed air and a drying solvent to flush it outand this is why i always use a new dryer and orafice/filter never had a failurebutt im with you i like to see 32. f at center consol good luck

[maxnix]

butt im with you i like to see 32. f at center consol good luck

Ideal is 34°F. Don't want freezing temperatures at the evaporator.

[elwesso]

I dont know if you could really get 34F at the center vents... Youd like the EVAP to be about 34F, but im not sure you could get 34F air...

I think a lot of my problem is I need window tint.. We took a trip north today to play some golf in our suburban.. the ac doesnt feel terribly colder, but it just doesnt let so much sun through.... I bet when Fred had the tint removed it may have removed some of the UV protection from the windows.

[maxnix]

34°F at the evaporator coils, about 36°F at the vent.

[DominickJ30]

i use compressed air

If there was a list of things never to do when working on any A/C system this would be number one on the list.

Compressed air+refrigirant = BOOM

[texasoil]

I think really accurrate temp sensors are in order. IF the refrigerant was boiling at 30F, then lowest fin surface temp reasonable is about 32-34F, and air temp at least 5F above that (10F temp approach is GREAT). But refrigerant temp that low will cause freeze-up for sure when blower slows down.

A charge that is a few ounces low will perform to specs when air temps are 80F or lower. It is when air temps get high and the hot refrigrant does not all condense (bubbles in the sight glass)that evaporator performance drops off quickly.A tight system is just that. My 94 Q45a with 153K miles has never had any refrigerant added and it makes spec performance, and cools really well here in Houston summers (hot, high humidity). Same with wife's 91 Qa, 160K--never any refrigerant in the 6 years we've owned it and still great performance. (just completed 700 mi cross country RT, mostly 70-75 +/-, mid day heat(93,96) 21.7 and 22.3 MPG on the freeway legs.

[Jesda]

It works? Good enough.

Spend the money refilling that NOS bottle!