This is what my A/C is reading.

[GTRON]

Head pressures are a bit higher with R-134a but performance is very predicable. I've never used those drop-in substitutes, they might work well, just be warned that a shop won't touch your system after you fill it with a non-standard refrigerant and also be aware of special procedures they might require. Redtek R-12a, for example, specifically says NOT to vacuum the system down - why, I have no idea.

There's also flammability. R-134a is basically non-flammable. Most drop-in substitutes are hydrocarbon based (butane, propane, etc). They claim to non-flammable but that would still make me nervous. The a/c system was not designed to contain a flammable gas in a collision.

Regarding oil quantity, use the factory fill amount for adding new Ester oil. The old oil is basically irrelevant at this point. You need a complete charge of the new stuff. I have a Honda PDF that says the system takes 8 oz total, you might want to double check this value but it would be a good place to start.

A/C service is really the low-hanging fruit of auto repair IMO as you are discovering. It's expensive to have a shop do it and it's really not that difficult to do. Keep at it and you'll have yourself a very useful skill and very useful set of shop tools!

Wow, again, so helpful, thank you.

I'm still confused about oil, LOL.
So, I'm going to do what you mentioned above. I need to buy a jug of ester oil, I'm going to fill the compressor and evaporator. How? How much? What oil do I put in with the 134a?

[masospaghetti]

Let's assume this Honda PDF is correct. It applies to Accords sold in different countries during that generation, so the cars are similar if not exactly the same. I think the a/c compressors are the same.

The total system requires 8 oz of oil, total. Since you are retrofitting from R-12 and the R-12 oil will not circulate with R-134a, you are basically assuming the system is dry. That old mineral oil will just settle out somewhere in the system. Where you put that 8 oz of oil is somewhat up to you. Normally, I would put half in the compressor and half into the drier (through the suction port) since the drier also serves as an oil reservoir. You put half in the compressor to ensure it has oil when it starts up.

You COULD put some of that oil in the evaporator instead of the drier but I don't think it really matters as long as you put some of it in the compressor.

If you add 8 oz liquid ester oil, don't add any more when you charge with R-134a. You want to add pure R-134a without oil, additives, or leak sealers. UV dye won't hurt though. If you add too much oil you will start reducing the system performance since less of the charge is refrigerant (which transfers heat) and more of it is oil (which does not transfer heat).

As an alternative to using the liquid ester oil you can also get oil in aerosol form and shoot it through the manifold before charging. BUT, the way you are doing it with liquid oil is better as it ensures the compressor is nice and lubed up before you turn it on.

[GTRON]

Let's assume this Honda PDF is correct. It applies to Accords sold in different countries during that generation, so the cars are similar if not exactly the same. I think the a/c compressors are the same.

The total system requires 8 oz of oil, total. Since you are retrofitting from R-12 and the R-12 oil will not circulate with R-134a, you are basically assuming the system is dry. That old mineral oil will just settle out somewhere in the system. Where you put that 8 oz of oil is somewhat up to you. Normally, I would put half in the compressor and half into the drier (through the suction port) since the drier also serves as an oil reservoir. You put half in the compressor to ensure it has oil when it starts up.

You COULD put some of that oil in the evaporator instead of the drier but I don't think it really matters as long as you put some of it in the compressor.

If you add 8 oz liquid ester oil, don't add any more when you charge with R-134a. You want to add pure R-134a without oil, additives, or leak sealers. UV dye won't hurt though. If you add too much oil you will start reducing the system performance since less of the charge is refrigerant (which transfers heat) and more of it is oil (which does not transfer heat).

As an alternative to using the liquid ester oil you can also get oil in aerosol form and shoot it through the manifold before charging. BUT, the way you are doing it with liquid oil is better as it ensures the compressor is nice and lubed up before you turn it on.

So you're recommending putting half of the recommended oil in the compressor, and half in the drier, is that correct? How do you put oil in the drier and compressor? That really detailed retrofit tutorial that that guy made said to coat the o-rings with oil when you replace them, does that apply to ester oil?
Thank you so much!!

[masospaghetti]

So you're recommending putting half of the recommended oil in the compressor, and half in the drier, is that correct? How do you put oil in the drier and compressor? That really detailed retrofit tutorial that that guy made said to coat the o-rings with oil when you replace them, does that apply to ester oil?
Thank you so much!!

That's right. You just pour it in. Both the compressor and drier have two ports, suction and discharge. Pour it in the suction port of each. Then spin the compressor a few times by hand to make sure the oil is moved around inside and not pooled up where it could "slug" when you fire it up the first time.

Yes you want to coat the o-rings with oil when you install them. This will keep them from tearing or binding up when you tighten the fittings down on top of them. I've used Ester and/or plain motor oil, neither is technically correct (you're supposed to use a special lubricant made specifically for this) but I have not had any problems.

Good luck and keep us posted!

[GTRON]

That's right. You just pour it in. Both the compressor and drier have two ports, suction and discharge. Pour it in the suction port of each. Then spin the compressor a few times by hand to make sure the oil is moved around inside and not pooled up where it could "slug" when you fire it up the first time.

Yes you want to coat the o-rings with oil when you install them. This will keep them from tearing or binding up when you tighten the fittings down on top of them. I've used Ester and/or plain motor oil, neither is technically correct (you're supposed to use a special lubricant made specifically for this) but I have not had any problems.

Good luck and keep us posted!

Thank you so much for the help! I made a big amazon order with all the stuff I'm going to need last night ($150 later..). Everything besides 134a, going to get that at Walmart.

I'll keep you guys posted, and of course, continue asking dumb questions!

[GTRON]

It's working!

Hey guys!
Quick update, (long story short), I replaced expansion valve, did O-rings, replaced drier, couldn't hold a vacuum, fixed the leak, A/C is working!

So I am waiting on a temperature gauge to ship to me, but I'm wondering what pressures I should be running, or how much r134a I should have in the system.
At the moment I think I have about 24oz in the system. (Hard to tell, because I used part of a can finding that leak)
How cold should I be expecting from my A/C system, that is designed for r12?
With the really slow car temperature guage thing I had, I read 45 degrees max from the vent(2500 rpms) with an outside temperature of 75-78.
The pressures I had at 75-78 degrees were, 35-45 low side 145-155 high side.

Thank you guys so much!

[masospaghetti]

Here is a good discussion on R-134a: http://www.peachparts.com/shopforum/...when-stop.html

System pressures are going to vary a lot depending on airflow through the condenser and whether you are using recirc or not, and the fan setting.

Also keep in mind a R-134a retrofit is not going to cool quite as well as a car designed for R-134a from the factory. The condensers for R-134a are larger. You might notice that at a stoplight where only the fans are providing airflow that the vent temperatures rise significantly, but when you begin driving the air gets really nice and cold. Every R-134a retrofit i've done works like this.

Basically what I'm saying is that your system pressures are about right!

This is also a useful guide for properly charging your system:

[GTRON]

Here is a good discussion on R-134a: http://www.peachparts.com/shopforum/...when-stop.html

System pressures are going to vary a lot depending on airflow through the condenser and whether you are using recirc or not, and the fan setting.

Also keep in mind a R-134a retrofit is not going to cool quite as well as a car designed for R-134a from the factory. The condensers for R-134a are larger. You might notice that at a stoplight where only the fans are providing airflow that the vent temperatures rise significantly, but when you begin driving the air gets really nice and cold. Every R-134a retrofit i've done works like this.

Basically what I'm saying is that your system pressures are about right!

This is also a useful guide for properly charging your system:

I'm going to wait until I get my kitchen thermometer in the mail, and do what some people on that forum said to do. It's working for now, I'm just wanting to make sure it's as cold as it should be, I'm going to need it when the 100 degree weather hits.