It’s getting hot. - Page 2 - PeachParts Mercedes-Benz Forum

123boy · #16 04-20-2022, 01:26 PM

Thanks for the info. I'll look into it and check some archives.

JHZR2 · #17 04-20-2022, 01:33 PM

Quote:

Originally Posted by 123boy

Be absolutely certain you know what you're getting involved with and the potential dangers. This quote is from another forum on the subject of alternative refrigerants.....

R12A is a hydrocarbon that is extremely flammable. You might recognize it by its more common name PROPANE. It will contaminate your entire system, and once contaminated, everything will need to be replaced, if you want to convert it back. The problem with R134A is that the smaller molecules of the gas, can penetrate the old rubber hoses, and that you also need to change the oil, flush the entire system of the old oil, and re-hose the entire system with barrier hose, if you want to do it correctly. With air conditioning, there are no short cuts, and using the wrong products devalues your car. It is your car, and you are free to do as you like, we can only advise you. I have seen how volatile an engine fire can be when the air conditioning hoses burn through, and the oil in the refrigerant lines starts to burn. It is like a flame thrower. I can image the same scenario with PROPANE in place of the R12 or R134A refrigerant. I can hear it now, when the flames hit the PROPANE, the flames will travel through the hoses, and all the a/c system will go BOOM, like a hand grenade. Don't want to be anywhere near when that happens.

So you’re reposting scare tactics without objective first hand evidence?

I’m not a 12a zealot, but I’ve indicated what and when I use it, and it has its place.

Putting ANY refrigerant into a leaky system is a combination of lazy and illegal. There are other hvac forums where the people are solidly anti-HC. Why wouldn’t they be? They effectively have a monopoly if CFC refrigerants are mandated and used. They’ll also tell you to NEVER use a sealant in your ac system because it fouls their recovery equipment. But how many r-134 or r-12 users put that trash in their systems effectively ruining them?

I’m curious how a properly done 12a system, using the correct blend filled into a vacuum, could explode inside the lines. Whomever wrote that has precious little clue, and you regurgitating it is not helpful.

Installing an HC gas in a car with a leaky evaporator is an issue (see my comment about not charging a leaky system). But leaking r-134a isn’t great either (see testicular cancer linkage).

Installing it in a leak free system does mean that you may have ten or so ounces of a readily dispersed flammable gas…. Next to eight quarts of oil and a pint, maybe more, of diesel. And 20 gallons in the back.

It has its place. I’m no fan of the variant that requires air mixed in other than the fact that it’s even cheaper to use as a diagnosis aid for systems that show zero refrigerant charge and thus you now that the r/d should be changed on it anyway.

JHZR2 · #18 04-20-2022, 01:40 PM

Quote:

Originally Posted by 123boy

Not really sure one way or the other. Until yesterday, I was unaware of R12a. I'll stick with R134a, for now. I'm just trying to nudge people to have respect for compressed gasses and ac systems. I think a lot of people are under the impression they can fix anything on a car so why should the ac be any different? Overcharging is no joke. It might not explode like a hand grenade, but shrapnel is shrapnel no matter its origin. Healthy respect, know you limitations and dont guess.
As always: A little knowledge can be a dangerous thing.

Again, it is illegal to put refrigerant, any refrigerant, into a leaky system.

R-134 has its own issues in the older HVAC systems in these cars that we love, when retrofit. 12a has some benefits there if the systems are leak free, and I’ve discussed the issues with blends before.

Leaky evaporators in say w124 or 140 cars create a paradox. It’s a 20-40 hour job to remove and replace. So what’s the plan? Condemn the car? Spend massive money in a car that has relatively limited value? Breather r-134 gas that can cause testicular cancer? Let HC slowly leak in your compartment waiting for a spark (recall that the concentrations need to be right and in a certain range to burn or explode).

123boy · #19 04-20-2022, 04:40 PM

Quote:

Originally Posted by JHZR2

So you’re reposting scare tactics without objective first hand evidence?

Not at all. Sorry if I gave that impression. I wasn't familiar with the R12a until I read about it here. Started to look around and found the quote I posted.
I think a lot of people (lacking knowledge and experience) will put just about anything in their system, leaking or not, if they think it's gonna give 'em some cool air on a hot day.

Thanks to advertising and marketing, all ya gotta do is.......(buy this can, with the little hose and cool little gauge with green and red zones, squeeze the trigger and "off ya go").

As I mentioned, I was only cautioning people. AC is pretty serious stuff. I commend you on your knowledge. You're the first person I've ever seen post here that exhibited a thorough understanding of gasses, vapor and pressures. Also NEVER heard anyone address the issue of the refrigerant blends changing their composition as they leak out and pressures fall, thereby changing the entire property of the gas.

Yes, it is a "paradox". I can't speak for every car ever designed, but I think MB kinda messed up by making their evaporators so ridiculously difficult to R&R. Hard to find fault with these old Benz's, but that IMHO is definitely one.

JHZR2 · #20 04-20-2022, 06:30 PM

Quote:

Originally Posted by 123boy

Not at all. Sorry if I gave that impression. I wasn't familiar with the R12a until I read about it here. Started to look around and found the quote I posted.
I think a lot of people (lacking knowledge and experience) will put just about anything in their system, leaking or not, if they think it's gonna give 'em some cool air on a hot day.

Thanks to advertising and marketing, all ya gotta do is.......(buy this can, with the little hose and cool little gauge with green and red zones, squeeze the trigger and "off ya go").

As I mentioned, I was only cautioning people. AC is pretty serious stuff. I commend you on your knowledge. You're the first person I've ever seen post here that exhibited a thorough understanding of gasses, vapor and pressures. Also NEVER heard anyone address the issue of the refrigerant blends changing their composition as they leak out and pressures fall, thereby changing the entire property of the gas.

Yes, it is a "paradox". I can't speak for every car ever designed, but I think MB kinda messed up by making their evaporators so ridiculously difficult to R&R. Hard to find fault with these old Benz's, but that IMHO is definitely one.

Agree it’s a design attribute that is lousy.

Can’t say that I’ve seen a claim to just add a squirt and it’s cool. Certainly not from HC vendors. I’ve seen that from r-134 at parts stores.

HC needs to be done right. But so does fixing refrigerant systems. Again, can’t be more clear on this that systems need to be fixed right.

It’s good that you’re investigating. There are lots of opinions out there. Many HVAC tradespeople have opinions but they also make money off of this. There is something to be said about their point that vendors don’t warranty compressors with other refrigerants. Question is why.

I don’t buy the flammability issues necessarily, but the question of comparability without doing it “right” is a question. Propane is a valid working fluid in terrestrial refrigeration so this isn’t just some fly by night concept.

vstech · #21 04-22-2022, 04:48 AM

Quote:

Originally Posted by 123boy

Be absolutely certain you know what you're getting involved with and the potential dangers. This quote is from another forum on the subject of alternative refrigerants.....

R12A is a hydrocarbon that is extremely flammable. You might recognize it by its more common name PROPANE. It will contaminate your entire system, and once contaminated, everything will need to be replaced, if you want to convert it back. The problem with R134A is that the smaller molecules of the gas, can penetrate the old rubber hoses, and that you also need to change the oil, flush the entire system of the old oil, and re-hose the entire system with barrier hose, if you want to do it correctly. With air conditioning, there are no short cuts, and using the wrong products devalues your car. It is your car, and you are free to do as you like, we can only advise you. I have seen how volatile an engine fire can be when the air conditioning hoses burn through, and the oil in the refrigerant lines starts to burn. It is like a flame thrower. I can image the same scenario with PROPANE in place of the R12 or R134A refrigerant. I can hear it now, when the flames hit the PROPANE, the flames will travel through the hoses, and all the a/c system will go BOOM, like a hand grenade. Don't want to be anywhere near when that happens.

Wow…

Well, there is some truth in your post… there is some propane in the mix…

Posting fearmongering misinformation isn’t a good plan…

Boom like a hand grenade… um… wow…

vstech · #22 04-22-2022, 04:51 AM

R290 or industrial propane is not for automotive use, it has completely wrong vapor pressures for use as an R12 replacement. The mixture used in 12A etc HC alternatives has isobutane or other modifiers to get the VP in line with automotive uses.

123boy · #23 04-22-2022, 09:43 AM

Quote:

Originally Posted by vstech

Posting fearmongering misinformation isn’t a good plan…

I hadn't heard of using propane as a refrigerant (besides RV refrigerators, which BTW work like crap) until reading about it here (as I already mentioned in a previous post).

I looked around and found a site talking about propane based refrigerants. Definitely got my attention. I simply thought, maybe, others would be interested. Am I to assume there's an argument about the flammability of propane?

"fearmonger" is a VERY strong term. Some might even consider it "mean", "abusive" and quite "offensive" to describe someone as such. I don't appreciate being referred to as a "fearmonger". I also apologize if anyone was "triggered" by the words "hand grenade".

Makes no difference, to me, what ANYBODY puts into the charge port of their automotive AC system.....knock yourself out (or, maybe I should say, "blow yerself up" heh heh).

No propane for me. Sounds dangerous and ill advised, to say the least.

As for the various companies that market this junk, they COULDN'T CARE LESS about your car or you. Their ONLY motivation is to SELL THEIR PRODUCT.

Good luck, to all, with the "alternative refrigerants of the future"......
Thankfully, I won't be needing any of it.

derburger · #24 04-22-2022, 10:37 AM

I've found a 14"x23"x44mm parallel flow condenser that might be the key to cold air in a W123. Other condensers are around ~20mm thick, and the rough measurements I've made suggests it'll fit a W123 240d. It would be easier than the dual condenser setups I've seen in a w123.

Cleaning the evaporator and adding a w126 aux fan + override switch has helped on my '80 240d, but the A/C system is still underpowered for hot summers.

Shern · #25 04-22-2022, 11:21 AM

“Sounds dangerous and ill advised”

Based on what, a single post you’ve read on an anonymous internet forum?

Once or twice a year my 72 year old mom forwards me a poorly compressed 10mb compilation of animals being cute.

Same energy.

123boy · #26 04-22-2022, 02:01 PM

Quote:

Originally Posted by Shern

“Sounds dangerous and ill advised”Based on what

Based on having a brain and the ability to think for myself. Also based on the knowledge of propane, what it is and what it can do if mishandled. Sorry I actually have an OPINION about something that's based on common sense and cognitive thinking.

As I've mentioned, several times in this thread, put whatever you want into YOUR automotive ac system.....I COULDN'T CARE LESS!!!!!

I'll save the propane for my BBQ grill......

Sorry about your mom, hope her posts have more energy (and interest), for you, in the future.

h3ffe · #27 04-25-2022, 10:12 PM

In your last post, you stated you didn't know propane is used as a refrigerant.

Now, you are talking about your knowledge of propane, then stating it's your opinion. I guess you don't know much about refrigerants or their flammability in general.

Please stop backpedalling and polluting this thread with your "common sense." Some of us are trying to swap useful, vetted/cited information.

...fearmonger

Quote:

Originally Posted by 123boy

Based on having a brain and the ability to think for myself. Also based on the knowledge of propane, what it is and what it can do if mishandled. Sorry I actually have an OPINION about something that's based on common sense and cognitive thinking.

As I've mentioned, several times in this thread, put whatever you want into YOUR automotive ac system.....I COULDN'T CARE LESS!!!!!

I'll save the propane for my BBQ grill......

Sorry about your mom, hope her posts have more energy (and interest), for you, in the future.

Shern · #28 04-27-2022, 10:49 PM

Well, I'm still alive.

I charged the system over the weekend. It was an interesting experience.

*Disclaimer* I have read much in the archives and I understand that I did not follow MB procedure to the letter. This is a learning experience and a fun hobby. Effing something up is often part of that.

Started by pulling a vacuum to 30hg (i believe that was the measurement) and holding it for an hour. Vacuum held so I ran the compressor for another hour to boil off any residual moisture in the system. Next, I attached a can of Duracool and bled the yellow line until I saw coolant venting. Charged until I reached 35psi on the low side and I can't recall what the high side was... maybe 180-200? more? I was paying more attention to the side I had immediate control over. Ended up using two cans. Slightly less than the factory equivalent of r12 (Duracool rep did the math and told me 15oz, 2 and a half cans).

A few observations:

First, I have to say, when the compressor is running now it is nearly imperceptible. That in itself is blowing my mind... I used to have to switch off the AC to do any high speed (lol) maneuvers eg merging onto a freeway, climbing a hill, pulling out of my Los Angeles driveway, thinking heavy thoughts. This is in part due to the Sanden compressor, but from what I've read, Duracool slugs the engine a lot less than r134a.

The temperature is about the same -feeling wise. I never really measured vent temps on 134a so I can't say whether it's better or worse. I did measure vent temps to today. At idle it's about 58 F. At speed, the vent temp drops to about 46 F. This is mostly stop and go LA traffic. I've yet to do any longer trips.

The compressor does an interesting cycle pattern (again, no baseline). It gets to about 46 and then cuts out (as observed through the rising vent temps) until the vents temp gets to about 56-58 degrees. Then it kicks on again and the temperatures drop. As a total amateur I have no idea what causes this, but something is responsible for this temperature range. I've read of a pressure switch at the drier, and I've read of an ETR by the evaporator. Curious if there isn't anything going on there... Seems odd the compressor would kick off at the mid to upper 40s. It falls pretty quickly until it hits that wall, then cruises back up until the upper bound.

Anyway, based on the performance increase alone, I'm very happy. Though I am wondering if there isn't another system component that deserves a closer look (specifically the ETR).

resago2000 · #29 04-28-2022, 09:52 AM

I have R-152 in mine. I had to adjust the txv 1/4 turn restricted to get the compressor to cycle correctly. R152 is a small homogenius molecule compared to the rest, so at first was flowing to much through the txv, not allowing it all to evaporate. works great now.

I have a '77 240d with an earlier engine. sanden compressor and largest PF condenser I could find that would fit.

links of pics of everything in my sig.

Shern · #30 04-28-2022, 01:26 PM

Hmm... I've found almost zero references to adjusting the TXV, though quite a few on adjusting the ETR. Have you any experience with that? Seems like the adjustment increment.