AC help please! So hot. I need proper pressures.

[bimmerteck]

Cool, glad to hear it worked for you. Pressures look alright with today's temps.

[bben76]

Success!

I don't know where in Nashville you are but if your anywhere close to me(south east Nashville) your welcome to come use my 5 cfm vacuum pump so you can be sure to get all the moisture out of the system. I'd hate to see you have to go around again.

Thanks Bimmerteck! I definitely would have taken you up on that. I left the cheap Harbor Freight vac on for about 2 hours, guess it worked.

Success! Got down to 42-43f vent temp on recirc. Ambient temp 75-ish. Not sure what Relative Humidity is today.



Hare are my gauge readings at 75 ambient temp:
Idle: low 43 high 210
1500 rpm: low 33 high 235

Idle


1500rpm


Is this good? Bad? It's cold now so something is working :D

I primed the lines to eliminate atmosphere.

I was a little worried during charging because the site glass on receiver/drier looked frothy again, but as soon as I got close to the right charge it cleared up. Now it's completely clear, this is good right?

I put in two 12oz cans, so 24oz and then added as close to 6oz of a third can as possible. To track how much was going in I kept my scale handy - I measured how much the can weighed new and then continued to remeasure its weight as it emptied.

The compressor seems to be cycling as I can feel the drag just a tiny when it clicks on and off.

This is where I purchased my remanufactured compressor: http://stores.ebay.com/compressorsoftheworld for about $130 (including s/h)

[bimmerteck]

I don't know where in Nashville you are but if your anywhere close to me(south east Nashville) your welcome to come use my 5 cfm vacuum pump so you can be sure to get all the moisture out of the system. I'd hate to see you have to go around again.

[scottinAZ]

you appear to be drawing almost 20" from what I see. Red scale is .5 BAR.

It wont hurt to open up the high side as well, but in reality, it wont make much of a difference.

[bben76]

ah ha, i see.

I've already mounted the compressor with 4oz by volume. So I decided to see what the difference really is.

Using water (b/c I don't have a lot of PAG left) I measured 4oz of water by volume and put it on the scale:



Turns out 4oz of water by volume when weighed is 4.3oz in weight. 3.7oz of oil (by weight) is what I drained out. So I overfilled by .6oz.

But maybe water density isn't the same as PAG oil? I checked, .5oz by volume of water is .6oz weight:



And .5oz of PAG oil volume is the same:



Very non-scientific but in the end I'm very close to what I drained out, within .6oz if I did this right.

------

Here's my next question. Using the Harbor Freight vacuum my air compressor can't hold the recommended 75-90psi. It settles and remains at 40psi when drawing the vacuum. Which results in this gauge reading:



Am I reading this gauge correct when I say I'm pulling only about .5inHG? Is this going to be sufficient to vacuum down?

I'm only drawing from the low side, should I be drawing down the high side too?

[bimmerteck]

A fluid ounce is a measure of volume, a dry ounce is a measure of weight.

You should measure the volume of oil that came out of the compressor rather than the weight.

[bben76]

Drained 3.7 ounces of nasty oil out of the compressor.



And refilled the compressor with 4oz of PAG 46. Is this the right PAG?

[bben76]

For the noobs (like me), here's a great write up on basic gauge readings

http://www.denlorstools.com/autoblog/2009/04/adding-freon-to-car-ac-gauge-readings-explained/

[bimmerteck]

no need for that just get colder temp switch from e36

YOU should stop giving advice on systems you don't understand the operation of. ;)

A colder temp switch in the radiator will make no difference in aux fan speed, or activation when the fan comes on during A/C operation. The A/C button on your dash is wired to command the low side relay to run the aux fan WHENEVER the A/C is on regardless of the temp switch.

It wasn't but a week ago you were asking r3v about aux fan's, how the 2nd speed is obtained, whether you need a pusher or a puller. Now here a little over a week later your going to tell me that I'm killing a compressor, then claim that the high side pressure has some bearing in the life of the aux fan's motor or control system, and insinuate that scottinAZ is wrong about bypassing the fans's resistor. (he's not, it's a cheap yet effective option for conversions needing more airflow at idle)

http://www.r3vlimited.com/board/showthread.php?t=210864

[immajackuup]

Kind of... the fan runs on two speeds factory.

Low speed may not provide enough airflow at high ambient temps.

This is why I hard wire my aux fans for high speed only operation.

no need for that just get colder temp switch from e36

[scottinAZ]

Correct me if I'm wrong, but shouldn't my aux fan either "work" or "not work?"

Kind of... the fan runs on two speeds factory.

Low speed may not provide enough airflow at high ambient temps.

This is why I hard wire my aux fans for high speed only operation.

[Ryann]

It was easier for me to run flush agent and compressed air through in reverse direction of what freon runs through it b/c I couldn't get the end of the air compressor and blow nozzle under the dash.

Probably actually a good thing. Any shit stuck to the TXV screen was blown out the other way.

What is reccomended for a conversion such as this is ester oil. will not react with the residual oil left in the system (no way to get it truly all out) the way that PAG and mineral will (totally unmiscable, so can cause issues with lack of lube)

I was given that same info by two separate people (bimmerteck being one of them) and used ester in mine.

This is why bben flushed his system. PAG performs better than ester.

As I have said before in other threads, a better option than any of these for our old r12 systems is to fix the leaks and recharge with r414b. ZERO oil hassles.

[agent]

most likely his aux fan is going to shit,even at at a dead stop it shouldn't be doing that.

Correct me if I'm wrong, but shouldn't my aux fan either "work" or "not work?"

[immajackuup]

If the condenser had no airflow and was run in a small and very hot garage with no airflow and 120 degree ambient temps all the time then yes it would kill the compressor, but roll the car down the road @30mph at 90 degrees ambient and the head pressures drop right down where they should be. ;) If he actually sat in traffic in the car I would recommend a higher flow aux fan. but that's what he has his e39 for.

most likely his aux fan is going to shit,even at at a dead stop it shouldn't be doing that.

[bimmerteck]

you're killing the compressor just to let you know.

If the condenser had no airflow and was run in a small and very hot garage with no airflow and 120 degree ambient temps all the time then yes it would kill the compressor, but roll the car down the road @30mph at 90 degrees ambient and the head pressures drop right down where they should be. ;) If he actually sat in traffic in the car I would recommend a higher flow aux fan. but that's what he has his e39 for.