Hi To All who helped. Especially those who cautioned that heater control valve heat needed a shut off.
I had one already and it did completely shut off any heat from flowing thru to the cabin air.
BUT, I found the vacuum feed (There was a splice near the master cylinder) to the HVAC controls had been accidentally disconnected by my mechanic when he replaced my master brake cylinder.
Therefore the recirculating door did not close allowing hot air from the outside to heat up the evaporator.
This explains why the cold air would shut down when pulling off to the side of the road after getting cold air on the highway and it never regained cold after that.
After the car sat overnight, it was cold again until it ran for a while and warmed up.
I am on my way to Lexington Kentucky on Thursday for a July 16 Concours just as another heat wave is going to hit.
Hopefully I can stay Cool as well as look Cool in my 300-F!!
Thanks to all,
I believe that filter is actually a muffler or so I was told or read somewhere to quiet or smooth compressor discharge / intake pulses . Maybe a filter in it too ?
I agree if ice it would melt . Good thinking , although might freeze again instantly if water remains at expansion valve . High pressure side gauge should tell you compressor or valve ? Sounds like valve . Or something hurting valve . They say tiny amount of dirt can clog expansion valve , a piece of junk from making the lines etc . That would be intermittant ? Pressure equalizes slowly , dirt falls back ?
The problem with vacuum is even if pumped for a week if you open to air while changing lines after vacuuming but before charging
due to unscrewing adapters all the benefit of extensive vacuuming is lost . I have seen people do that . They think it is ok !! Adding some freon puts a positive pressure in system air will not be sucked in . Same problem happens with Mitsubishi split systems . I have many scars on wallet due that issue.
I do not understand how more freon than needed impacts anything in a good direction . Tread lightly there . It is not arbitrary amount , once receiver is full enough . Although a bigger / smaller receiver might impact that . Can you tell level in receiver by temp of wall ( feel it ) ? Should be down an inch or two from top .
Sent from my iPhone
Hi To All My Cool Friends,
"NO flow implies a compressor problem (valve issue maybe) and FREE flow implies an expansion valve staying too openâ•ˇ MG
Classic Air and the mechanic agree with Marshall in that it either has to be the expansion valve or compressor. Already replaced the expansion valve once with NOS because the system would not cool enough on initial charge.
After this initial replacement, we got great cooling but after a period it stops not to restart until the car sits overnight then on cold start up it cools great again but eventually stops. BTW, The cooling did not effectively start until they increased the charge from 2.5 to 4 lbs.
"An intermittant action has a high probability of being ice.â•ˇ
I would think that if it was an ice block, running at highway speeds with system off for 15 minutes should cause thawing thus allowing it to cool again when turned on. Doesnâ•˙t start cooling again until the car sits overnight.
"Expansion Valve doesn't shut off the flow, it really turns off the clutch, to stop it.â•ˇ
There is no connection to the compressor blue wire thru the expansion valve. It has a bulb sensing evaporator temperature and opens and closes accordingly.
Compressor clutch is controlled by temperature switch with a bulb sensing evaporator temperature instead of EPR pressure valve. I thought the previous statement "It actually allows passage at a given temp and STOPS it at a lower tempâ•ˇ was correct.
AND hoping the expansion valve is defective and shuts down after a period? by mis-sensing the temperature at the bulb next to the evaporator.
Hopefully, a new expansion valve will fix the problem.
"What is a filter bulb ?"
See photo below (A â•˙62 set up in my â•˘60): 300 group will not see this.
If it isnâ•˙t the expansion valve, then the damn compressor has to go back to Classic Air under guarantee.
They also are talking about having the evaporator sent to them and building a more modern expansion valve into it.
Will have the system pulled down under vacuum overnight.
Drier is newly renewed as well as the 2 filter bulbs to and from the compressor. The compressor was rebuilt.
Generally the high pressures are good with the low pressures not being as low as they would like.
There are no leaks. There is UV dye in system. No problems.
Hopefully the replacement of the expansion valve, vacuum down will occur Monday night and recharge on Tuesday.
If you're not finding a cold spot somewhere in the system that can only mean that you have either NO flow of refrigerant or else FREE flow. NO flow implies a compressor problem (valve issue maybe) and FREE flow implies an expansion valve staying too open. In either case the problem should be immediately noticed by reading pressures on the HIGH side and LOW side. Hasn't someone checked pressures yet?
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---------- Original Message ----------
From: "Tony Rinaldi awrdoc@xxxxxxxxx
To: Ray Jones <1970hurst@xxxxxxxxx
Cc: Tony Rinaldi <awrdoc@xxxxxxxxx
>, Chrysler 300 Club <Chrysler300@xxxxxxxxxxxxxxx
Subject: Re: [Chrysler300] Problem With Converting To 134A
Date: Sat, 9 Jul 2016 23:59:44 +0000 (UTC)
Now that we have that all straightened out.
I will insist for an overnight vacuum pull down to minimize any moisture.
My receiver/dryer is newly rebuilt by Classic Air.
I have been told that we need to put another expansion valve and that my symptoms can be caused by a bad unit.
Ray just stated:
"This is the cold LOW pressure liquid, going thru the expansion valve where it starts to become a gas again. This valve mostly regulates the amount of flow which regulates temps. It actually allows passage at a given temp and STOPS it at a lower temp.
First: I get great cooling inside the cabin from a cold start.
The line that empties the evaporator, after it is fed thru the expansion valve and the evaporator, is cold as is the filter bulb that feeds the condensor. This line becomes hot and the cooling stops after 10 minutes.
Second: I get great cooling at highway speeds, pull off to check the temperatures and the cooling stops and never returns even after shutting off the A/C for 10-15 minutes and turning it back on.
Compressor is engaged. There is no visible frost.
Compressor is controlled by a temperature controlled switch that shuts the compressor off if evaporator coil freezes.
Soon, if everything works extremely well then it craps out without any visible freezing.
Does anyone think that we are on the right track and it sounds like a bad expansion valve?
Also, it works better with 4 lbs. of 134A than with the recommended 2.5 lbs. which is 70-80% of normal? 3 lbs.
Does that reinforce a bad expansion valve.
PS I heard that you guys have enough R-12 to carry you thru until Y3K. Ã°Å¸Ë˛â™≥
Sent from Yahoo Mail for iPhone
On Saturday, July 9, 2016, 6:54 PM, dverity@xxxxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:
I hate to say it Keith, but you got some wrong too. The compressor takes the low pressure gas from the evaporator and turns it into a high pressure gas. The compressor cannot compress liquid any more than an engine can. The high pressure gas Ã¢â≠¬Å„condensesÃ¢â≠¬ËΩ in the condenser and becomes the high pressure liquid. When it hits the expansion valve, it goes to a low pressure, low temp liquid and is evaporated into a low pressure gas by the air flow over the evaporator. It then goes back to the compressor and the cycle starts all over. High side is hot, and low side is cold. Any cold on the high side means a restriction.
Don, with an equally cold 66 Imperial.
Sent: Saturday, July 09, 2016 5:35 PM
Subject: Re: [Chrysler300] Problem With Converting To 134A
Hate to say it Ray, but you got most of that A/C info backwards. You might want to check out a tutorial like this one:
The compressor actually turns the gas into a pressurized hot liquid. The liquid goes through the condenser coils up by the radiator where it partially cools off. This is normally referred to as the "high side". Then it flows to the expansion valve just before the evaporator coils. The high pressure of that liquid is released at the expansion valve, turning it to a very cold gas there and becoming the "low side". This makes the coils cold and they absorb heat from the air passing through them. The low-side gas, which is still quite cold, then returns from the evaporator to the compressor to be compressed in to liquid state again.
One part you did get right is the critical importance of system evacuation before charging with freon. Because low pressure cause liquids to turn to gas, when you vacuum the system for several hours it causes the contaminating liquids, including water and oils, to boil into a gaseous state and be drawn out by the vacuum pump, and thereby cleansing the system before freon charging.
And one final tip: If you can't or don't want to buy a new receiver/drier (which is your A/C system's garbage can) it is possible to "rejuvenate" your old one. Use an old toaster oven - which you probably keep around anyway to bake paint on small parts. Take it out into the garage or outdoors and bake the receiver/drier in it at 400 degrees for a couple of hours. It may stink to the high heavens, but that process will boil out whatever garbage is in there - same as turning on your self-cleaning oven. Give it a new coat of paint, bake it again at 250 for 15 minutes, and it will look and perform like a brand new champ again.
Freezin' a can of beer in front of my '57 A/C
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Posted by: Tony Rinaldi <awrdoc@xxxxxxxxx>
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