greenquark

After 2 years without A/C I decided to fix it. I went to the specialist today to maintenance the AC system.

The guy didn't have the adapter for the high pressure valve to connect the hose.

The perfomed a 10 minute vaccuming through the low pressure valve only. Refilled the system with refrigerant and the vent didn't throw cold air. I said the high pressure line was not vacuumed he said:

1. The system can be serviced/ vacuumed through the low pressure port, without using the high pressure port.

2. The system must have clogged somewhere so the machine didn't performed a correct vacuuming.

3. Most likely is the expansion valve, and not to worry about replacing the dryer (eventhough I told them I have not used the AC for years).


Any thoughts about this?


Questions :

1. What is the correct amount of refrigerant used for this car? honda accord 1990 dx already retrofitted for r134a refrigerant .

2. What is the correct retrofit extension for the high pressure port? ( Mine is a bit thicker than the tire valve) .

fcm

An A/C system can be serviced from just a low side service port, some cars, [some Volvos] only have a low side service port, however to properly test/diagnose an A/C system you need both the low and high side service ports

Both the r12 service ports need the R134a adapters, there is one size low side and two sizes of high side, the smaller high side is the same size as the low side, yours must be the bigger of the two.

FYI a proper retrofit requires

1- an A/C flush, to remove all R12 refrigerant oil, removal and draining of A/C compressor
2- replacement of filter/dryer.
3- removal of service port Schrader valves and installation R134a service ports, both high and low.
4- replacement of all the R12 Orings.
5- the correct amount of R134a refrigerant oil, Ester oil works well, half in filter half in compressor, an oz. of C4 oil in compressor is also a good idea.
6- a nitrogen pressure test at 250PSI for at the very least .5 hr, the longer the better, I do overnight,
7- a min..75hr vacuum before recharging with the correct amount of R134a refrigerant that is about 80% of the R12 charge.

Oil, [ester] is 4oz + 1oz C4 oil
Refrigerant, [R12] is 32oz so about 27oz of R134a.

Find another A/C shop, one that does not have both retrofit high side service ports is the wrong shop also one that only does a 10 min. vac is also the wrong shop.94

greenquark

Thanks for the info ,


When I told him about the 10 min vac, when I asked more than 30 min because the AC has been off for more than a year, he said the machine was automated, it would stop by itself...I pressed the high port valve showing him there was still stuff in the system!

He also said that the high pressure port was only necessary when the condenser fan was not operating, since in my case it is, no need.

And not to worried about replacing the dryer...that was the last straw ...

He was going to put 2 pounds of refrigerant , too.

As you suggested I will replace as much as I can by my self , then try to find someone to do the vac/refill with the correct amounts you posted here.


To be sure, I need the system with at least 75 hour vaccumed before doing the refill ?

Thanks in advance

holmesnmanny

it's .75

greenquark

Quick question.

Since I cannot find the high pressure port adapter around here, I will end up going to a u-pick. Do I have to look for Honda 1990-1993 or Any japanese car pre 1994 with the conversion made, would work ( the high pressure port adapter that any car pre 1994 might have?

holmesnmanny

You should have no problem finding a 90-93 accord with a 134 high pressure port adapter

masospaghetti

The conversion fittings are standard and any half-decent auto parts store should stock them. Here ya go:
Doesn't sound like this a/c "specialist" really knows what's he's talking about just based on what you've said so far. Yes, you can service and vacuum the system down just by using the low pressure port, but not replacing the drier is a very big mistake. The part literally costs $7 on Amazon. You should replace the drier, vacuum the system, recharge, and do a proper diagnosis. The expansion valve is inside the car and it's quite a bit of work to access it, you don't want to replace it unless you really need to.

You really need to get a high port adapter and then connect a gauge manifold to the system to see what the pressures are. You will be able to tell, very quickly, if the expansion valve really is stuck closed. Are you sure the compressor is even turning on?

fcm

Ditto the above^^^, the specialist, is not very good, any good shop would have both the low and high side retrofit service ports, and would have told you you needed the dryer, [it is saturated with pad/mineral oil and needs to be replaced, also I know of no automatic A/C machine that does not allow adjustments for vacuum time out, [test to see if vacuum holds] and recharge amount.

Also system needs to be flushed to remove the Pag/mineral oil, the desiccant is also most likely saturated with moisture, [very bad for A/C].

Last but not least not needing the high side if condenser fan is working is just so much more bull ****, you need to know what both the high and low side pressures are as compressor cycles, it will literally tell you what's wrong with the system, obviously he did not even check the vent temp. or he would have known system was not working, find another shop.

According to my numbers 2 lb, [32oz] is an overcharge and can be as bad or worse then an undercharge it can/will lead to high head pressure and a loss in cooling. 94

holmesnmanny

It actually is best to replace the expansion valve if it hasn't been replaced already. Besides a leak, expansion valves are the number one reason for an ac system not working right. The third would be the compressor is bad. On our car it's not as hard as you would think. You just disconnect the two lines in the engine bay that go to the evaporator and then there are four evaporator case bolts, after removing the glove box, then pull out the evaporator case. Don't forget to unclip the thermostat connector. Sometimes you need to gently unbolt the heater core case bolts a little bit that sits next to it to wiggle the evaporator case out.

greenquark

Thanks so much for all the info. I finally got the two retrofitting valves an the dryer and the o-rings kit. Up here in Canada is a bit different to USA :/ . I saw a kit with pump and gauges for 130 USD in amazon.com...you cannot find it in amazon.ca ...

I will proceed as you guys say, install valves adapters, replace o-rings, dryer and see.

IS there a way I can evacuate the oil from the compressor without dismounting it ? In my car I have to take off power steering and alternator to get the compressor out. It is a pain. I was wondering If I could bleed the compressor some how and out Ester oil in it.

A friend is trying to convince me of using Duracool refrigerant. He swears by it, and he says is more efficient and easier on the compressor than the R134. What is your opinion on this guys?

Yes the compressor engages. Since I could not read the high pressure valve I don't know IF it is working properly. Any way to know ?

Thanks again


PS: When the A/C system was tried I could swear I was hearing a hissing sound, maybe coming from the passenger vent, but I am not 100 % sure

I did have a leak on the high pressure schrader valve which I replaced.

greenquark

How do I know if the expansion valve is stuck closed?

fcm

Duracool contains butane/propane as the refrigerant, both are hydrocarbons a will void any warranty on any new A/C parts installed, it will contaminate your gauge set as soon as you connect them and any other A/C system the gauge set is connected to.

The only time I would use Duracool or RedTec or anything other then R12 or R134a is if the system is already contaminated, even then I would flush the system and use R134a.

You must remove the compressor to flush it, 94

greenquark

I am having a hard time taking apart this part... what size is the nuts on the left? I tried with expansion wrench but it was a no no. I need to buy that size wrench ( the low pressure size) ..suction hose side....Once I take those two out...Evaporator could be checked

masospaghetti

I haven't done that particular fitting but a standard Crescent-style adjustable wrench usually works well on A/C lines.

I think you should check the system properly before you tear it apart, your expansion valve might be fine. Sometimes leaving an old system alone is less troublesome than disturbing a bunch of old fittings and seals.

If you get a proper gauge set you can tell if the expansion valve is stuck shut based on the pressures inside the system.

fcm

Ditto the above, get/rent a proper gauge set, although the expansion valves are a common problem, they are a pain to install and can result in leaks if not done exactly right, best to find out if it is a problem first.

Don't forget to remove the Schrader valves from the R12 service ports before installing the R134a retrofit service ports. 94

greenquark

Well I am beating myself for not reading this before...I got my hands into it I am in the middle of a big mess. I finally Got the two nuts off ( 24 and 27 mm )

I was thinking of replacing as many o-rings as possible and leave it alone. Then I decide to take out the evaporator to clean everything out.

I took all the nuts off , AC band, So the evaporator is lose. But I don't see how I can pull it out. Even the dashboard doesn't allow it. In other words, it is not as easy as the manual says :/

EDIT: I am such an idiot. I was trying to pry off the fan instead of the evaporator. I couldn't do anything else and went back And corrected the problem. Once I took the evaporator out, I could put back the fan ....

I tried and blew air... I was asking the new and the old gods I didn;t break anything in this process. And it worked.

I will post pictures later so you guys advice me what to do...

greenquark

Update:

This is how the evaporator looks like:






The stuff around the expansion valve looks like oil.

How do I test the expansion valve?

I must say I blow air and there is no resistance to it . It passes through

holmesnmanny

It's actually a good thing you pulled out the evaporator because as you can see the expansion valve is leaking and that evap core is caked up with crud. You can just imagine blowing air across that crud and it blowing into the vents and into your face. You can clean off that one or just get another. I would get another since you can't tell if that core is leaking as well or possibly its just the orings leaking in that area.

fcm

Replace the valve, it is only $16.95 from Performance Rad... https://shop.performanceradiator.com...39_20268_20269

Replace any/all O rings of connections you have undone, DO NOT reuse O rings, they will leak.
Do not forget to oil, [C4 oil is best, but Ester oil will work] the O rings as you install them and keep everything clean, even a spec of dust can be a problem. 94

enzoferrari

Cleaning the evaporator and the A/C temp switch makes it a lot different. I did mine a few days ago and it's a whole new thing now.

If your compressor works about 20 to 30 seconds and idles about 20 to 30 and you don't get cooled, it's more likely that your A/C components are good, but with a clogged evaporator or a leaking heater valve, the air doesn't get cooled. Clean it up!

greenquark

Well. I finished cleaning the evaporator , replaced every o-ring, put it back. I tried the fan , and the improvement in air flow is as day and night. My daughter thought I already had fixed the AC!

Since I am no expert I am a bit doubtful about taking out the compressor , and replacing the oil. I have a friend that will do the vacuum and check for leaks... and I will put the R134 ... My concern is the amount of oil. How do I know how much oil do I need to put in? Do I get a can with R134 and oil ? What oil should I use? Ester or PAG ?

Any ideas?

masospaghetti

From Honda's service manual (it's for a JDM Accord so may be slightly different) they recommend 5/6 oz of oil for evaporator change and 1/3 oz of oil for dryer change.

Since you don't know how much oil is really in there it's always a guess without totally flushing it out. I might add an extra ounce of oil just as a precaution, too much oil will reduce system performance, so weigh that with the risk that there's not enough oil in there.

Regarding oil type I've done quite a bit of reading on this and there's no real concensus. Ester is typically used for retrofits but the new "DEC" PAG oil is supposed to be more stable than the old "SEC" PAG oil, which would react with the trace chlorine from R-12 and form corrosive compounds. Still I would use Ester. You can get a 2 oz can of aerosol Ester oil and shoot it in, or you can get a bottle of liquid oil and add it directly to the dryer.

greenquark

Great,

One question though. You say to add 1 oz of oil , but to get a 2oz spray can. I am guessing the 2oz can has 1oz of oil in it? more or less?

What I am thinking of doing is : Replaced all o-rings I can, check for leaks . Vacuum the system if it holds vacuum, then replace Dryer ( I already got it) then , vacuum again , and fill it up.....sounds correct?

fcm

As the dryer needs replacing anyway replace it before you add oil or do a vacuum.

If your doing a proper retrofit then removing and flushing the compressor is the only correct way, it also allows you to install the correct amount of oil, 4 oz ester and 1 oz C4 and that can be split between the compressor and the new dryer. 94

masospaghetti

I meant add 5/6 oz + 1/3 oz + 1 oz (as a precaution), but since this is all a guess anyway, just add the 2 oz can of oil and call it a day.

Replace the dryer first, then vacuum the system down, then add oil, then refrigerant. No reason to vacuum the system before the dryer change.