R4 A/C compressor noise

[plpeyton]

You can close the valve to the can before opening the high side valve.

Not something I want to risk on a fingertight o-ring seal...jus saying

 

[plpeyton]

You can close the valve to the can before opening the high side valve.

I sincerely doubt the high side has a problem. I have a parallel flow condenser and the R4 actually makes more racket with less refrigerant in the system. Pretty sure the parallel condenser I'm using requires actually MORE refrigerant than less of the original tube and fin design. It's thick, 16"x26" by about 7/8 or 1 inch thick, that combined with the endcaps contain enough room for quite a large amount of refrigerant, not to mention reduced high side pressures, especially when air is blowing through it. No good way to get a good high side reading anyway, the pressures change too much between sitting and idling and driving (10 or 15 psi low side) the orifice tube is from a 91' as well, and I did that on purpose so system pressures would correspond with the AC pump from the 91'. Low side pressures correspond with the ambient temperature according to the r-135a charts. Extremely unlikely the high side would be off in comparison.

 

[someotherguy]

I sincerely doubt the high side has a problem. I have a parallel flow condenser and the R4 actually makes more racket with less refrigerant in the system. Pretty sure the parallel condenser I'm using requires actually MORE refrigerant than less of the original tube and fin design. It's thick, 16"x26" by about 7/8 or 1 inch thick, that combined with the endcaps contain enough room for quite a large amount of refrigerant, not to mention reduced high side pressures, especially when air is blowing through it. No good way to get a good high side reading anyway, the pressures change too much between sitting and idling and driving (10 or 15 psi low side) the orifice tube is from a 91' as well, and I did that on purpose so system pressures would correspond with the AC pump from the 91'. Low side pressures correspond with the ambient temperature according to the r-135a charts. Extremely unlikely the high side would be off in comparison.

Cool story. Why let facts get in the way of it? You may want to have someone that knows what they're doing have a look, with gauges, and experience.

Richard

 

[plpeyton]

Well, at this point I have a working A/C unit. Take that FACT. I've used the guages and have enough experience with the system. I didn't come here to argue. I want to hear other people's experiences with R4 compressors. Typical shops and AC guys either won't touch it, or wind up up the same results I ALREADY HAVE, after thousands more dollars of labor and parts. I've had shops that wanted to put in new parts when I already had the exact same new parts already on the vehicle. I want to hear about people that have had experience with the R4 in particular, especially since it's been branded a HIGH FAILURE UNIT. I'm considering changing to either a scroll compressor or a Sanden unit. I'm not here to discuss STUPID about what I already KNOW.

 

[Schurkey]

1. We've determined for certain that you don't know how to use a manifold gauge set.

2. We've determined that your system is probably over-charged by a full can of refrigerant; although condenser size may affect how much it's over-charged.

3. We've determined that you may not have a suitable orifice tube for the new refrigerant.

4. We have not determined if you've got way too much oil in the system, 'cause you've not answered my question about that.

My educated-guess based on the above, is that your high-side pressure is so high it's affecting compressor reliability.

The R4 compressor does not have the bullet-proof reputation of the A6. However, most of that reputation was developed in the first few years of R4 production. Later years seem reasonably reliable. In other words...they built it crappy, then developed it into a decent product after a few model years.

 

[someotherguy]

Well, at this point I have a working A/C unit. Take that FACT. I've used the guages and have enough experience with the system. I didn't come here to argue. I want to hear other people's experiences with R4 compressors. Typical shops and AC guys either won't touch it, or wind up up the same results I ALREADY HAVE, after thousands more dollars of labor and parts. I've had shops that wanted to put in new parts when I already had the exact same new parts already on the vehicle. I want to hear about people that have had experience with the R4 in particular, especially since it's been branded a HIGH FAILURE UNIT. I'm considering changing to either a scroll compressor or a Sanden unit. I'm not here to discuss STUPID about what I already KNOW.

Got it.. good luck

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[plpeyton]

I'm thinking I got the wrong orifice tube. Yeah, I'm going to tend to pattern off of the 91' because that's the year model of the pump. However, even that's tricky because everything has changed with the advent of having to use R134A refrigerant. I'm just now finding out that I maybe need a black orifice instead of white to compensate system pressures correctly. I'm getting a lot of variance on the low side and the high side both because of lack of air flow through the condenser at idle. Still, none of that really explains the racket the r4 is making. The thing started groaning like a dying bull the second it started cooling. GM didn't really change a whole lot over the years from early 80s to the mid 90s. They all used the R4 compressor. What I'm finding our is that the R4 isn't really suited for the higher running pressures of the R134A; they were originally designed for R12. The retrofits just don't seem to be able to hold up from everything I'm hearing, so I have decided to go with an R4 style Scroll Compressor from UAC and yet another 16x26" condenser. I think the compressor will last longer and be a lot quieter, even if it doesn't cool as well. I'm looking for recommendations on the orifice tube. So far, I've seen people use blue and orange. THe guy that used the orange didn't seem to have much success. High side was way too high in comparison to the low side. I'm also considering a variable orifice tube. It's supposed to help with hot conditions and lots of idling (stop lights in town). Posting a link for the scroll compressor I have ordered.

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[L31MaxExpress]

I'm thinking I got the wrong orifice tube. Yeah, I'm going to tend to pattern off of the 91' because that's the year model of the pump. However, even that's tricky because everything has changed with the advent of having to use R134A refrigerant. I'm just now finding out that I maybe need a black orifice instead of white to compensate system pressures correctly. I'm getting a lot of variance on the low side and the high side both because of lack of air flow through the condenser at idle. Still, none of that really explains the racket the r4 is making. The thing started groaning like a dying bull the second it started cooling. GM didn't really change a whole lot over the years from early 80s to the mid 90s. They all used the R4 compressor. What I'm finding our is that the R4 isn't really suited for the higher running pressures of the R134A; they were originally designed for R12. The retrofits just don't seem to be able to hold up from everything I'm hearing, so I have decided to go with an R4 style Scroll Compressor from UAC and yet another 16x26" condenser. I think the compressor will last longer and be a lot quieter, even if it doesn't cool as well. I'm looking for recommendations on the orifice tube. So far, I've seen people use blue and orange. THe guy that used the orange didn't seem to have much success. High side was way too high in comparison to the low side. I'm also considering a variable orifice tube. It's supposed to help with hot conditions and lots of idling (stop lights in town). Posting a link for the scroll compressor I have ordered.

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I have used the white, blue, red and orange in a factory R134a system. The high side pressure stays the same. The low side pressure drops with the smaller orifice. I run the 0.062 Red and it gets ice cold. The Orange 0.057 cooled even better at idle but caused the compressor to cycle frequently at highway speed. Will also add the systems I have worked with are dual evaporator and all use an expansion valve in the rear.

Get a genuine Sanden compressor with a GM style rear head. You won't be dissapointed.

 

[plpeyton]

Thanks for the input on the orifice tube. I'm positive a Sanden compressor would do excellent, but, at the moment, I'm trying to work with what I have. To put a Sanden in, I'd really be required to spend a lot on hoses and lines to make that work, and the expense AND wait on that is something I'm trying to avoid. (I'd have to order in some hard line and have new hoses made, plus acquire the tools/services to bend the hard-lines, and/or acquire a more suitable condenser for the 73', ideally a parallel flow unit that would qualify as a direct replacement. I'm not ready to spend that much money and time on it just yet. This is more of an experiment to find something affordable that works and is reliable. Based on what you're telling me about your experience with orifice tubes, I'm thinking I may try an automatically adjusting orifice tube that is recommended for numerous GM applications. It starts at .062 (which is also exactly 1/16") and depending on conditions, restricts flow even more for conditions where the vehicle is hot and idling. I seem to be having trouble with my low side pressure dropping enough in relation to my high side. This last go around, I used a bigger condenser than last time, but for some reason, my high side pressures seem to be dropping (I can tell by the lack of heat coming off of the lines per refrigerant low side psi). I'm thinking maybe a faulty compressor from the get go, right out of the box, or somehow, despite my efforts to flush the system, something may have gotten left behind and immediately got in there. I'll be working with a guy I know that has a shop here in town to set up the Scroll Compressor because he has more tooling and a bit more knowledge than me working with AC. He's had a few successful retrofits where so far, I really haven't. Not very many people are really ready to set up a custom AC system from scratch, which is pretty much what I'm doing. Most shops won't even touch it unless it's a factory system using factory recommendations, and anyone else around this area that's known just quite simply, bleed people's bank accounts dry. I've been able to get mine to work and cool, last setup I did lasted for the summer last year, then the R4 started pooping out. The set up I have now is mostly the same as last year, except for a larger condenser because the system didn't seem to be cooling well enough per refrigerant charge (I had to lose too much refrigerant to get the thing to cool, hence a larger condenser and opening up the airflow a bit more, got rid of my transmission cooler that I don't think I needed anyway, the cooling lines to the radiator are more than sufficient) Last year, I used the white 1/16" orifice tube with a 14"x24" condenser and an additional electric fan. This year, I've duplicated that setup with a larger condenser (16"x26" and THICKER also), lost the trans cooler that was blocking airflow but unfortunately also had to lose the electric fan because it won't fit. As of the moment with my present set up and second attempt, it seems I'm headed the same direction as last year, I'm having to lose too much refrigerant to get the system to cool......and that dam R4, if it isn't making a ton of racket, it isn't cooling. This is why I'm headed towards the Scroll Compressor and an orifice change. I have a link for the orifice I'm considering. https://www.oreillyauto.com/detail/...981-gmc-c1500-pickup-rwd?q=orifice+tube&pos=2