Checking For Black Death

[kings1527]

Now that summer is upon us, I'm anxious to figure out what I need to do/purchase/install to get my AC going again.

What's the best way to check for "black death" in my system? As I understand it, if black death is found then a new compressor, hoses, evaporator (might as well do the heater core too), and accumulator are all in order.

Thanks!

Alex
6575

[vwdmc16]

how llong has it been since your system cycled? is there any refrigerant inside?

[kings1527]

how llong has it been since your system cycled? is there any refrigerant inside?

Honestly, I have no idea. I'm not sure what the PO had going on with it. There is no refrigerant in the system and I have no idea how long the system has been void. I disconnected the lower hose on the condenser since it was rusted on and a fair amount of oil came out. That's about all I know.

Someone mentioned one time to access somewhere in the system and look inside with a flashlight to look for black death. Where can I do that on the DeLorean?

Thanks.

[Bitsyncmaster]

Pull the orifice and look at the screen on it. You will know instantly if you will need a high pressure flush. I think if I were doing my system again, I would replace the condenser which is the hardest to flush clean.

[WelmoedJ]

Dave's advice is sound.
However since you mention the system being empty for a long period of time there's more to do.

You need to replace all seals (o-rings) after flushing the system.
You also need to replace the accumulator (dryer).
As an extra insurance you may want to replace the low and high pressure switches.
Drain the oil from the compressor.

Then have the system nitrogen pressurised for let's say 24 hours to see if it's leak-proof.
If OK, the next things are:
- use (ester) oil to refill the compressor
- fill the system with either R-12 (if available) or R-134A
- have some flour added for easier leak checks afterwards

Mind that summer is not the proper time to start checking an A/C system.
Checking should best be done before the season (e.g. end or winter/begin of spring).

[Ron]

- have some flour added...

Were you hungry when you posted this. lol

fluorescent dye

[kings1527]

Pull the orifice and look at the screen on it. You will know instantly if you will need a high pressure flush. I think if I were doing my system again, I would replace the condenser which is the hardest to flush clean.


Thanks Dave, I'll pull the orifice tube and see what I have. I know it's not at the condenser. Is the OT located at the accumulator?

And is "black death" curable with a high pressure flush? I was under the impression that I have to replace everything rather that do a high pressure flush. But if the flush works, then great.

I just replaced the radiator and upgraded the fans and coolant expansion tank to SS a couple days ago. That would've been a great time to do the condenser, too. I think it's OEM and I definitely wouldn't mind going back in there and putting a brand new condenser if it needs to be done.

Alex
6575

[Bitsyncmaster]

Thanks Dave, I'll pull the orifice tube and see what I have. I know it's not at the condenser. Is the OT located at the accumulator?

And is "black death" curable with a high pressure flush? I was under the impression that I have to replace everything rather that do a high pressure flush. But if the flush works, then great.

I just replaced the radiator and upgraded the fans and coolant expansion tank to SS a couple days ago. That would've been a great time to do the condenser, too. I think it's OEM and I definitely wouldn't mind going back in there and putting a brand new condenser if it needs to be done.

Alex
6575

OT is in the tubing going to the evaporator. Don't expect a fill the units with solvent and blow them out with air to clear enough crud to not have to do it again (maybe a few times). If you see a lot of black crud, get as many new parts as you can afford. The evaporator can be cleaned to save you the work of replacing it. The higher speed you can flush solvent, the better job it does cleaning.

[jfirios]

what a coincidence, I was just about to start looking for info on represurizing the ac system. I am in the same boat but don't know how long the system has been empty of coolant. Is this something that any garage can do, or should I have the guys at DMC Cali do it. I know they send cars out to another shop for presurizing. What do you all think.

[kings1527]

OT is in the tubing going to the evaporator. Don't expect a fill the units with solvent and blow them out with air to clear enough crud to not have to do it again (maybe a few times). If you see a lot of black crud, get as many new parts as you can afford. The evaporator can be cleaned to save you the work of replacing it. The higher speed you can flush solvent, the better job it does cleaning.

Thanks again, Dave. I'll check all t his out.


what a coincidence, I was just about to start looking for info on represurizing the ac system. I am in the same boat but don't know how long the system has been empty of coolant. Is this something that any garage can do, or should I have the guys at DMC Cali do it. I know they send cars out to another shop for presurizing. What do you all think.

That is definitely the beauty of this board. I always figure someone out there is having the same problem as I am. As far as I know, the AC system (R12) isn't any different than any other car out there. So I'd imagine any shop out there can do it. The only hiccup might be finding an AC service facility that won't be afraid to deal with an R12 system, even if there isn't any refrigerant in the system. It might be as simple as them not even having the fittings for an R12 system. I didn't know DMC Cali farms out there AC stuff. I'm sure they deal with a shop in the area that handles R12 systems. Those shops are getting tougher to find. I went around to a few in my area and asked them if they service R12. By the looks on their faces, you would've thought I was asking them if they sell plastic explosives. I like DMC Cali but I want to do as much on my car as I can. It's a good learning process and it saves $$$.

If I find out that I'm going to have to replace several parts (i.e. hoses, compressor, condenser), then I'm just going to go ahead and convert it to R134a. It wouldn't make any sense at all to put that kind of money into new parts and keep it R12.

Alex
6575

[kings1527]

BTW, if you're dealing with any parts that are rusted, whether they're bolts or AC hoses that are rusted together, I HIGHLY recommend Break-Free.

http://www.break-free.com/

I've had some rusted parts and I haven't run into anything yet that Brake Free wasn't able to handle. For the really bad stuff, you might have to hit it pretty good with the stuff and leave it overnight, but that's better than breaking something off. Just work the part slowly when you first start so you don't break anything.

Hit it with Break Free and then work it back and forth until you get some play, and then hit it again to flush out the old rust that's coming off and help it penetrate deeper and keep that process going until you get what you need. It gets rusted parts going again like they're brand new.

Alex
6575

[jfirios]

had anyone converted their cars ac from the R12 to the R134a system? Is it a big deal to do? Is there any retrofitting that needs to be done?

[nullset]

had anyone converted their cars ac from the R12 to the R134a system? Is it a big deal to do? Is there any retrofitting that needs to be done?

You need to thoroughly clean and flush everything, and make 100% sure that you get all of the oil out and replaced. The oil used in R-12 systems is not compatible with R-134a.

If there's currently R-12 in your system, try to find a shop to evacuate it for you. They probably won't charge anything if they get to keep the R-12. That's stuff's getting expensive.....

--buddy

[David T]

The easiest way to check for contamination is to undo either end of the high side hose (the one on the left side of the car) and look inside. If it is not clean and shiny the system is contaminated and needs to be flushed at least. Trying to inspect the OT is difficult and I would not touch it unless the system is confirmed to be contaminated. If the system has been at atmospheric for an extended period of time figure you have to replace at a minimum:
3 hoses
dryer/accumulator
refrigerant oil
refrigerant
service valve cores
Other things can include the belt, idler bearings, fan motor. Unless someone already converted and burnt the system up it should not look too bad inside. You may have to clean the condensate drain hose once you get it running. The typical job starts because the 30 year old hoses leaked and the system gets to atmospheric for a while. Air gets in and with that moisture. Usually not too bad but it has to be done correctly and without damaging parts, some of which are delicate.
David Teitelbaum

[Bitsyncmaster]

It would not be wise to not replace the orifice tube on any AC system work. If you can't get it out then take it to and AC shop. The orifice tube has to have a clean screen and to not replace it is asking for trouble.

[David T]

Normally I would agree with replacing the OT but because it is so hard to do and so easy to damage the pipe, and so hard to replace the evap coil, I would not recommend replacement unless you can confirm contamination.
David Teitelbaum

[jfirios]

i saw this youtube video where this guy ( think it was posted on this forum) but he was saying to turn the AC on high and spray Lysol right into the intake of the AC unit. That will pull the cleaning solution right through the whole system killing any mold that might be growing in the AC unit. just be sure to have the doors open and let it vent out for a while after spraying the system.

[jawn101]

i saw this youtube video where this guy ( think it was posted on this forum) but he was saying to turn the AC on high and spray Lysol right into the intake of the AC unit. That will pull the cleaning solution right through the whole system killing any mold that might be growing in the AC unit. just be sure to have the doors open and let it vent out for a while after spraying the system.

I don't know if that's a good idea, I would classify Lysol as a contaminant in a system that should only contain refrigerant and oil.

[stevedmc]

i saw this youtube video where this guy ( think it was posted on this forum) but he was saying to turn the AC on high and spray Lysol right into the intake of the AC unit. That will pull the cleaning solution right through the whole system killing any mold that might be growing in the AC unit. just be sure to have the doors open and let it vent out for a while after spraying the system.


http://www.youtube.com/watch?v=VrVc_FXrbHY&feature=relmfu

[stevedmc]

You might want to reconsider wrenching on 30 year old AC connections. Check out this article.

http://www.dmcnews.com/Techsection/r134_v2.html

[nullset]

You might want to reconsider wrenching on 30 year old AC connections. Check out this article.

http://www.dmcnews.com/Techsection/r134_v2.html

If your system is leaking, you should fix the leaks, period.

It's irresponsible AND ILLEGAL to fill a leaking system, with R134a or R-12. I don't care what anyone else says about "it works for me" or "i don't care about the EPA".

-buddy

[dmc6960]

i saw this youtube video where this guy ( think it was posted on this forum) but he was saying to turn the AC on high and spray Lysol right into the intake of the AC unit. That will pull the cleaning solution right through the whole system killing any mold that might be growing in the AC unit. just be sure to have the doors open and let it vent out for a while after spraying the system.


I don't know if that's a good idea, I would classify Lysol as a contaminant in a system that should only contain refrigerant and oil.



http://www.youtube.com/watch?v=VrVc_FXrbHY&feature=relmfu

Thats for cleaning out the exterior of the evaporator. Not the issue here. The issue here is cleaning out the insides of the compressor, hoses, condensor, evaporator, etc.

[stevedmc]

Thats for cleaning out the exterior of the evaporator. Not the issue here. The issue here is cleaning out the insides of the compressor, hoses, condensor, evaporator, etc.

Hey mentioned a youtube video of someone spraying lysol. I thought I would post it for clarification.

[stevedmc]

If your system is leaking, you should fix the leaks, period.

It's irresponsible AND ILLEGAL to fill a leaking system, with R134a or R-12. I don't care what anyone else says about "it works for me" or "i don't care about the EPA".

-buddy

And if it isn't leaking, you shouldn't just replace everything just to do it. He might only need a good flush and a new compressor.

[DMCMW Dave]

I don't know if that's a good idea, I would classify Lysol as a contaminant in a system that should only contain refrigerant and oil.

I think he meant blowing it through the air handling part, not the liquid freon part, i.e. it would come back out the vents. There are automotive products aimed at the same thing, to kill molds on the outside of the evap core.

[jawn101]

I think he meant blowing it through the air handling part, not the liquid freon part, i.e. it would come back out the vents. There are automotive products aimed at the same thing, to kill molds on the outside of the evap core.

Ah, OK - I can't see the videos from here so if I was mistaken then I apologize :) Thanks Dave

[Ron]

I wouldn't spray something that says "79% Ethanol/SD Alcohol" on it into an intake port a foot or two away from a running electric motor.

Not to mention "Health Rating 1" = ("Minimal risk when used as intended")...a little heat can do odd things!

[jfirios]

so has anyone changed over from the r12 to the r134 system? was it expensive to do?

[jawn101]

so has anyone changed over from the r12 to the r134 system? was it expensive to do?

Search the forum... there are about a hundred threads on the topic. Many have converted and there are many opinions on how much it can/should/does cost. Starting that discussion here will derail OP's thread in a big way.

[stevedmc]

so has anyone changed over from the r12 to the r134 system?

Yes.



was it expensive to do?

No


http://www.dmcnews.com/Techsection/r134_v2.html

[Chris4099]

http://www.dmcnews.com/Techsection/r134_v2.html

There are a couple of serious flaws in that procedure. First is flushing the whole system. Every book on automotive AC says not to flush the dryer (I would assume this damages the desiccant). Next is not changing out the oil. While most oil does stay in the compressor, it does come out and therefore needs to circulate. Mineral oil which was used with R12 will not circulate with R-134a. You must replace with Ester oil. PAG works too, but will react with old mineral oil and R12 molecules still remaining in the system. Therefore it's critical to flush the whole system if using PAG. Finally, the link mentions using engine vacuum. Very bad as it's not sufficient to remove moisture. Instead rent a vacuum pump from Auto Zone for free.

Back to the previous topic, just about everything on my D seems to be well rusted in place (I broke nearly every stud on the exhaust for example) but I was able to disconnect all the AC connections with no issues. I just made sure to soak them for several days with PB Blaster. Then using good wrenches and having a firm grip, I was able to break loose the fittings with minimal effort. When I removed the orifice tube, it actually pulled right out with no issues. I do understand some can be stuck in there real well and have heard of people damaging the evaporator getting it out, but that doesn't always happen. Getting the new one back in was actually more effort on my part!

So when inspecting for black death, there's no reason in my mind to not pull the OT and replace the accumulator.

[Ron]

You might want to reconsider wrenching on 30 year old AC connections. Check out this article.

http://www.dmcnews.com/Techsection/r134_v2.html



No

http://www.dmcnews.com/Techsection/r134_v2.html

There are a couple of serious flaws in that procedure.
...
Sadly, what you mentioned is not the worst of it.


Steve,
I'm curious as to what you would say if someone following the procedures in your link turned a can of Freon "upside down" (which delivers a liquid vs gas) to "empty it faster", and it locked up their compressor and destroyed it, because no liquid can be compressed -- "It worked for me/Bill" ?

Yeah, I've heard of a lot of people getting away with it too -- But that is because they are usually dumping it into the system through a service port upstream of the compressor (usually at or near the Accumulator or Receiver-Dryer) where it has a chance to expand into a gas/vapor there, and as it runs through the line(s), before it gets to the compressor. With Delorean service ports mounted at the compressor, the liquid has no chance to expand at all!

Also, note that AC technicians are taught to not use use the old trick of using a small torch to look for small leaks because burning R12 is highly dangerous. I don't mention this because Bill suggests burning leaks -- Instead, he instructs one (after ambient pressure is reached) to run the entire volume of the system through the engine!
Google "burning R12", "Phosgene gas", "WWI".

[Bitsyncmaster]

Using engine vacuum to remove R12 is deadly. The exhaust is burning the R12 and very deadly. Vent or recover the R12 first.

Engine vacuum has been used for may years to evacuate auto AC systems. It's just not capable of removing much water if there is any in the system. The purpose of the dryer is to hold any left over moisture in the system. I bet a new dryer would work fine 99% of the time with 20 inches of vacuum when charging.

You could charge with liquid if your letting the liquid flow at very low levels. But it's something I never do. It only saves you from heating the can of freon.

[stevedmc]

Using engine vacuum to remove R12 is deadly.

Yep. Thats why I always say a person should "properly evacuate" a system before pulling vacuum on it. Personal, I don't use my engine for pulling vacuum. I invested about $100 for a pump a year or so ago and I've used it to service 3 cars since then. In my opinion having a vacuum and set of gauges is a good investment. Another good investment is going to Big Lots and buying about 25 cans of r134a at $8 a can.

[David T]

"Back in the day" we used to use a propane torch with a modified head that had the flame burning on a copper "reaction plate". The head had a hose that you used to suck in the air around any suspected leaks and fed it into the flame. When the flame turned green you knew you were burning freon. We also had "Carbon Tet" fire extinguishers. If the fire didn't kill you the toxic gasses would! We all like to think we are a lot smarter now (those of us that survived!). They also sold a set-up where you would remove a spark plug, screw an adapter in with a hose and run the motor and pump up your tires! We also used to use the compressor in the system to pull a vacuum on the system itself but cars never had the service valves to isolate things so you could do that, only on the larger commercial systems. Those were the days when we had Ammonia systems. When they leaked you KNEW it! It amazes me as many survived as they did with all of these unsafe practices!
David Teitelbaum