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Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

Lightbulb Out posted:

I went to Autozone and well


That's not gone well.

I mean.....what's the temperature? I assume that's a static pressure (motor off and for a least a few hours). I'd expect to see the in the mid 80s to low 90s on a system that could be somewhere between "low charge but with some liquid refrigerant" and "all the lines are full of refrigerant and this will explode as soon as you turn on the compressor".

If there is any liquid at all in the system the static pressure will be the exact same given it's temperature, and this is in a range I believe possible.

Good start to diagnostics, but that's all it is.

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Lightbulb Out
Apr 28, 2006

slack jawed yokel


No the car is off - that was after the car had been sitting for 2 or so hours. 78 degrees.

The blower has been running well, but I just hear a relay clicking the compressor on and off. I can feel it while driving, and hear it when sitting. It also seems to trigger the A/C fan.

I suppose it could definitely be a relay or switch of some kind.

Lightbulb Out fucked around with this message at 02:09 on Jul 9, 2019

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

Lightbulb Out posted:

No - that was after the car had been sitting for 2 or so hours. 78 degrees.

The blower has been running well, but I just hear a relay clicking the compressor on and off. I can feel it while driving, and hear it when sitting. It also seems to trigger the A/C fan.

I suppose it could definitely be a relay or switch of some kind.

Do the readings on the gauges change when the compressor cycles on? That's the next reading you need.

E: I think my videos are still in one of the OPs to show you what this looks like.

Lightbulb Out
Apr 28, 2006

slack jawed yokel


I am out of light - I will do this tomorrow.

I was just spooked to see it reading in the *~danger zone*~ but you are right - I need to see what its like with the compressor on. The gauges I have don't have the nice R134a temperature gauge.

I will re-read the OP yet again and watch the video.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

Lightbulb Out posted:

I was just spooked to see it reading in the *~danger zone*~

Lol, I didn't even recognize those markings because I only look at the numbers. Yeah, "danger zone" on low is accurate.....IF THE COMPRESSOR IS RUNNING. It's not, which is why both the low and high are the same reading.

Lightbulb Out
Apr 28, 2006

slack jawed yokel




Ok that's with the compressor on, it's been about 80-85 degrees ambient. The static pressure with the compressor off was closer to 100psi on both sides off compared to around 95psi on Monday after it had sat longer.

I believe that tells me I'm a candidate for additional refrigerant?

STR
May 12, 2006

I thought I was a nice jester


Definitely.

STR fucked around with this message at 02:58 on Jul 11, 2019

Lightbulb Out
Apr 28, 2006

slack jawed yokel


I got it up to about 35psi on the low side, high side didnít move much. I heard hissing when I disconnected everything which is concerning, but I still have cold AC. I also had issue with my can tap - Iím not sure if it was freezing up or I wasnít patient enough or what. I had to fiddle with the valve on the can to get a pressure increase when opening the low side valve at times.

I was able to confirm my drain line is clear! And feel a lot more comfortable with this process!

Thereís more in the can but I ran out of light and the neighbors showed up to ask me about what I was doing.

Molten Llama
Sep 20, 2006


Basic question: Are these instructions relying solely on static pressures to determine when you've reached proper charge? The answer seems to be yes, but the last time I did this was on a vehicle with published operating pressures, so I'm out of my element here and want to avoid blowing poo poo up.

My current patient is my partner's MINI, for which BMW couldn't possibly imagine publishing anything but a full vac-charge dose weight. I'm planning to check Mitchell1 when I swing by the library, but 98% of their MINI content is just the dealer Workshop Manual, which would give me only what the engine bay label already does. (410 g, +/- 10g, which is useless to me, the dude in an 0.75-car townhome garage with a manifold gauge set.)

IOwnCalculus
Apr 2, 2003





Refrigerant doesn't care who made the system. Last I checked BMW wasn't bending any laws of physics, so that temperature/pressure chart STR posted should still be very much in the ballpark.

Also, scales exist. I admit it's fiddly as gently caress to balance a can on a hose on a scale but it's definitely possible to get a reasonably close weight with home-gamer hardware.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

Molten Llama posted:

Basic question: Are these instructions relying solely on static pressures to determine when you've reached proper charge?

Static pressures on a non-clogged system should be IDENTIAL, because that's how these systems work.

The chart is running pressures.

Molten Llama posted:

My current patient is my partner's MINI, for which BMW couldn't possibly imagine publishing anything but a full vac-charge dose weight. I'm planning to check Mitchell1 when I swing by the library, but 98% of their MINI content is just the dealer Workshop Manual, which would give me only what the engine bay label already does. (410 g, +/- 10g, which is useless to me, the dude in an 0.75-car townhome garage with a manifold gauge set.)

410g is the only number you need if the system is empty. You can buy small cans and estimate on the last one, or use a typical digital kitchen scale (tare it with the last can you only need a part of, put some in, close the tap and weight it again, etc).

Lightbulb Out
Apr 28, 2006

slack jawed yokel


Update: the car drives better because it doesn't seem to be short cycling the compressor as often. I am going to get the pressures to line up more with the chart when I have a chance, but this definitely changed the way it was acting in a positive direction.

Thanks for the help and the thread Motronic! This was extremely helpful in helping me get a real understanding of how A/C systems work, which have always been a bit of a black box for me, having never had to really deal with one.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

Whoohoo, a thread success!

Molten Llama
Sep 20, 2006


Motronic posted:

Static pressures on a non-clogged system should be IDENTICAL, because that's how these systems work.

Right, that I get.

It's the thread's running chart that's throwing me, as it's both miles off from the charts Denso/Chrysler have provided for my last two personal vehicles,(mostly at the high ambient end, which is what I'm stuck dealing with in Phoenix), and slightly off from the charts Mini forums have found God-knows-where.

A couple psi and I wouldn't have blinked an eye, but e.g. at 100į, my Denso chart lists a range a full 10-20 psi lower on the low side, and the questionable Mini forums charts have their low-side max pressure lower than the thread chart's min pressure.

Motronic posted:

410g is the only number you need if the system is empty. You can buy small cans and estimate on the last one, or use a typical digital kitchen scale (tare it with the last can you only need a part of, put some in, close the tap and weight it again, etc).

It's got enough of a charge to be semi-functional and I don't want to accidentally vent anything to atmosphere, so the scale's unfortunately out.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

Molten Llama posted:

Right, that I get.

It's the thread's running chart that's throwing me, as it's both miles off from the charts Denso/Chrysler have provided for my last two personal vehicles,(mostly at the high ambient end, which is what I'm stuck dealing with in Phoenix), and slightly off from the charts Mini forums have found God-knows-where.

A couple psi and I wouldn't have blinked an eye, but e.g. at 100į, my Denso chart lists a range a full 10-20 psi lower on the low side, and the questionable Mini forums charts have their low-side max pressure lower than the thread chart's min pressure.


It's got enough of a charge to be semi-functional and I don't want to accidentally vent anything to atmosphere, so the scale's unfortunately out.

You're not going to hurt anything charging to the lowest pressure you can find on any of those sources and then checking vent temps, driving around to make sure it doesn't freeze up.

Optimal is great, but really not required for the system to function. Even to function at peak performance most times. It just means that a lo charge weight is gonna get you back in there sooner. It's better than too much.....and even some too much is gonna be fine, just reduced performance unless it's so much extra that you're slugging the compressor.

Molten Llama
Sep 20, 2006


Yeah, my general plan was to go conservative, I just wasn't sure where the huge discrepancy was coming from or whether my vision of conservative lined up with non-compressor-slugging reality.

And now, back to the garage before an unwanted $40 Stop Leak MaXXX ICE BLAST gauge bottle shows up.

InitialDave
Jun 14, 2007

I want to believe


Welp, looks like the Daihatsu system isn't actually gastight, AC has gone back to nonfunctional after a couple of weeks being sat.

Still at least I know it does nominally work, just need to find where the leak is at some point. I called ATS and they say they do have UV dye in their stuff, so with any luck a blacklight might pinpoint the issue.

We shall see. Not the end of the world.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

InitialDave posted:

I called ATS and they say they do have UV dye in their stuff, so with any luck a blacklight might pinpoint the issue.

You should be in good shape. Off to ebay/amazon.......

InitialDave
Jun 14, 2007

I want to believe


Motronic posted:

You should be in good shape. Off to ebay/amazon.......
I already have a small one, the tubeless sealant I use on my mountain bike is UV dyed too.

But this is a relatively low priority job versus some of the other car-related nonsense on my immediate plate, so ehhhh. See how I get on for an opportunity to do something about it.

spankmeister
Jun 15, 2008








Slippery Tilde

Is there such a thing as a 12v vacuum pump that y'all can recommend? I don't have power available at the parking lot where I do most of my maintenance so when I do final get around to fixing my Golf's AC I want to evacuate the system using the car's power, if at all possible.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

spankmeister posted:

Is there such a thing as a 12v vacuum pump that y'all can recommend? I don't have power available at the parking lot where I do most of my maintenance so when I do final get around to fixing my Golf's AC I want to evacuate the system using the car's power, if at all possible.

I doubt such a thing exists. If it did, you'd need a lot more than the energy stored in a single car battery to do the job.

STR
May 12, 2006

I thought I was a nice jester


Molten Llama posted:

Basic question: Are these instructions relying solely on static pressures to determine when you've reached proper charge?

If the car uses a variable displacement compressor, then some of this goes out the window, and it really should be vacuumed + charged by weight.

STR fucked around with this message at 07:43 on Jul 12, 2019

BonoMan
Feb 20, 2002


Jade Ear Joe

Coming over from the short dumb questions thread.

I have a 2008 Honda Civic (base model... the LX? Not sure - inherited from my wife).

The A/C blows but not cold air. Last year I got the freon replaced and it worked fine. I seem to remember the mechanic mentioning a bad relay and/or clutch to me.

Well this week it goes kaput. I *thought* it was low refrigerant. I bought a thing from Autozone but the pressure gauge, when plugged into the L, was right near the top of the green so I guess it didn't need anything (per the directions).

I also thought the clutch was not engaging, but it turns out... it's not DISENGAGING. If I turn the A/C off it disengages, but once I turn it back on, it clicks-hums then never stops spinning unless I turn the A/C off via the button. Is this freezing me up? I noticed that when the A/C button is off the air is super hot (central Mississippi in a black car gently caress me) and when I turn it on it does cool a *little* but not enough to actually cool the car down.

Today I switched some relays out and it seems to do the same.

Am I wrong on the clutch? It should go for a bit then turn off right? Then rinse repeat? When the car is first cranked does it just run for a long time to get started?

edit: Just checked again with a different brand refrigerant gauge and it was, with the clutch running constantly, reading just above green into the yellow.

edit 2: Looking at other forums, it seems these Civics can have problems with the HVAC panel sending always on signals to the clutch? Ughhhhh god I can't afford a new car.

edit 3: Okay! Progress! After testing the HVAC diagnostic and clearing codes, I decided to take it for a spin and manually engage/disengage the compressor clutch by just pressing the A/C on/off button. Success! Cold as ice air!

So it looks like my freon is fine and my relay works (ish... not sure if this the problem). Just that the compressor clutch is receiving the always on signal. Apparently I need a new (2009-2011 since they have the fixed problem) climate control unit. Ordered one from a 2010 model. We'll see!

BonoMan fucked around with this message at 21:27 on Jul 22, 2019

IOwnCalculus
Apr 2, 2003





Are the passenger vents cold at all?

You need to get a high side gauge on there as well.

If the air never gets cold, I don't think this is anything your HVAC control could be doing. Even if it's not ever disengaging the compressor and freezing up the system, you should get some cold air for a bit until the evaporator core ices over.

BonoMan
Feb 20, 2002


Jade Ear Joe

IOwnCalculus posted:

Are the passenger vents cold at all?

You need to get a high side gauge on there as well.

If the air never gets cold, I don't think this is anything your HVAC control could be doing. Even if it's not ever disengaging the compressor and freezing up the system, you should get some cold air for a bit until the evaporator core ices over.

Just updated the above posting.

However in regards to this... it would be semi-cool for a few minutes before moving back to room temperature. (and if I turned off the A/C button it was flat out hot) So it looks like the system is freezing even before it gets really cold? That would be par for the course for this car. Ever since I've had it, even when in perfect working order, it would take a while to get cold cold. So I'm guessing it's just freezing before that happens. Especially since manually cycling seems to let it get super cold after a while.

PainterofCrap
Oct 17, 2002

Hey bebe





Well, I pulled vacuum on the 2001 (not a 2000) Accord V6 on Saturday.

It was 108˚ so the pressures I was shooting for were ridiculous (55 low, 320 high). Pulled it for 45-minutes with my trusty, brand-new $95 Horror Freight pump & it held fast in the red, so at least there's no leaks.

Fed in the first can; compressor kicked on, air started to chill; the pressures started to see-saw like normal...took forever to empty that can, and after ten minutes, the needles stopped; pressures never rose above 30/120 thereafter & the compressor never shut off.

Then that fabulous chilled air disappeared.

Hello, new expansion valve & a lovely day of ripping apart the dash! Tell you what: the passenger seat is coming out for this one.

PainterofCrap fucked around with this message at 00:47 on Jul 23, 2019

IOwnCalculus
Apr 2, 2003





BonoMan posted:

Just updated the above posting.

However in regards to this... it would be semi-cool for a few minutes before moving back to room temperature. (and if I turned off the A/C button it was flat out hot) So it looks like the system is freezing even before it gets really cold? That would be par for the course for this car. Ever since I've had it, even when in perfect working order, it would take a while to get cold cold. So I'm guessing it's just freezing before that happens. Especially since manually cycling seems to let it get super cold after a while.

I think you're probably onto something there. Seems weird that the HVAC would fail compressor-on, but not impossible.


PainterofCrap posted:

Hello, new expansion valve & a lovely day of ripping apart the dash! Tell you what: the passenger seat is coming out for this one.

I'm so, so sorry. In hindsight I wish I had pulled the passenger seat out on my CR-V to do it because gently caress THAT JOB.

BonoMan
Feb 20, 2002


Jade Ear Joe

IOwnCalculus posted:

I think you're probably onto something there. Seems weird that the HVAC would fail compressor-on, but not impossible.




Yeah apparently clutch failing to always on is a known issue with the 2006-2011 Civics because of course it is.

Suicide Watch
Sep 8, 2009


Thanks for the great first post, OP! My a/c crapped out a week ago and I've just ordered a gauge set to diagnose the problem. I'm hoping it's not a system leak but UV dye will tell.

Two questions to start:
- how important is it to purge the service line prior to opening the low pressure valve to add refrigerant?
- are those cans of R-134a that include UV dye okay, or is it better to add it via the service line?

Thanks, I'll have more questions sure to come when the gauge set comes in.

Motronic
Nov 6, 2009


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Grimey Drawer

Suicide Watch posted:

Thanks for the great first post, OP! My a/c crapped out a week ago and I've just ordered a gauge set to diagnose the problem. I'm hoping it's not a system leak but UV dye will tell.

Two questions to start:
- how important is it to purge the service line prior to opening the low pressure valve to add refrigerant?
- are those cans of R-134a that include UV dye okay, or is it better to add it via the service line?

Thanks, I'll have more questions sure to come when the gauge set comes in.

There's not much you're going to be able to to to purge the service line realistically as a home gamer doing a top off. It's a minimal amount of air.

Dye in refrigerant cans is good. Sealant and/or oil is bad.

RIP Paul Walker
Feb 26, 2004



Motronic posted:

Sealant and/or oil is bad.

I totally understand the issue with sealant, but why is oil in the can bad? I saw one of those on the shelf a few weeks ago and it seemed like a decent idea (assuming itís the correct oil).

IOwnCalculus
Apr 2, 2003





Unless you're dumping a whole can in, you don't know how much oil you're putting in. Better to measure it and put it in a line before you pull a vacuum.

Motronic
Nov 6, 2009


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Grimey Drawer

RIP Paul Walker posted:

I totally understand the issue with sealant, but why is oil in the can bad? I saw one of those on the shelf a few weeks ago and it seemed like a decent idea (assuming itís the correct oil).

Because you're not going to be getting oil in very well using a set of gauges and a service hose. You have no control over how much you put in other than "some of it" or "all of it". Maybe "none of it" if you're really careful about can position.

I prefer to fill the service line with a syringe that attaches to the line. This is when the system is in vacuum already at the beginning of a refill.

I'm not sure why you would want to add oil if you are just topping a system off, but if there is a reason you can still just detach the service line from the gauges and fill it with the syringe with the exact amount you want.

RIP Paul Walker
Feb 26, 2004



That makes sense, youíre talking about those cans that are almost 100% oil tho right?

I was thinking of those cans that have mostly r134a in them with 0.5 or 1oz of oil mixed in, which seems like maybe kind of a good idea. Itís good to know itís mostly just an issue of not being able to measure vs. something horrific like what the sealers do.

rdb
Jul 8, 2002
chicken mctesticles?

So AC thread I have a dilemma...

Vehicle is a 2001 GMC yukon with rear AC controls.

Ac doesnít work. Compressor doesnít come on. Previous owner says he had it diagnosed as a clutch. It still has lots of refrigerant in the system, i hooked up my gauges and when I released them a lot came out from a sticky old Schrader valve which I replaced. Relays and fuses are good, and jumping across the low pressure switch does nothing.

My choices are replace the clutch, I think I have a small 3 jaw puller that will work, and OíReilly has the part for $140 or rock auto for $110. This is assuming the compressor still turns which because of its location I canít verify.

Or I can buy a complete compressor kit for like $180 with all the trimmings like a new receiver dryer and a poo poo ton of o rings and new oil. I have a beat up vacuum pump my wife uses for her milking machine and a set of gauges that measure vacuum but not in microns. I think I could do it either way.

Its just a question of which way is the right way. New clutch on an old compressor or new compressor of cheapest quality. What do you guys think?

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

Have you found the compressor clutch relay and tried to bridge it yet to see if it's actually a clutch that doesn't work? That would be my step 1.

rdb
Jul 8, 2002
chicken mctesticles?

Motronic posted:

Have you found the compressor clutch relay and tried to bridge it yet to see if it's actually a clutch that doesn't work? That would be my step 1.

I will give that a shot. I did swap relays around and put the DRL relay in the AC spot (DRLs worked and still do), but I did not jump any pins or probe for power.

I was debating smacking the clutch with a hammer but its not in a good location, nor is it my vehicle.

Colostomy Bag
Jan 11, 2016

C-Bangin' it



Ok, this one is a little out there.

Have a 2007 S600. Sometimes the blower comes on, sometimes it doesn't. Doesn't come on sometimes with AC or heat set for max so rules out temp sensors. You'll be driving around and in 5-20 minutes it decides to do its thing. Or it will just work the minute you start your car.

So researching this, it appears to be a "somewhat" common problem. They redesigned the blower so it has more protection from crap that falls through into the blower chamber and exposed motor.

I've already decided to replace the blower. Fortunately it is a somewhat easy fix, as in not ripping the dash out. Just back breaking under the dash removal of a panel type thing. People have had success removing the blower and cleaning it out, works ok, etc. My luck with that is about zero, and the new improved blower is around $120 for basically OEM.

So that brings me to the resistor. https://www.rockauto.com/en/catalog.../+resistor,6557

Seems quite simple on the inside, but the price is sort of ugggghhhh moment while I'm in there moment.

Not sure if to spend the coin on that. Basically looks like a fancy starting capacitor to me.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

I'm not sure how the hell that one works, but the old school ones are bypassed when the fan is on high - it's typically the easiest way to tell if the blow motor resister needs to be changed.

That one is.......special. And I'm guessing it's got something to do with a continuously variable fan speed.

If the cap on you old one isn't bulged out it's probably fine. And for $135 I would absolutely take that SOB apart and replace the cap for $1.25 rather than buy a new one.

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Colostomy Bag
Jan 11, 2016

C-Bangin' it



Motronic posted:

I'm not sure how the hell that one works, but the old school ones are bypassed when the fan is on high - it's typically the easiest way to tell if the blow motor resister needs to be changed.

That one is.......special. And I'm guessing it's got something to do with a continuously variable fan speed.

If the cap on you old one isn't bulged out it's probably fine. And for $135 I would absolutely take that SOB apart and replace the cap for $1.25 rather than buy a new one.

Yeah, like I said...odd one. Is it the blower or a bulging cap? Around 13 years old. Housing looks like it is thermo welded on so a dremel and futzing with it all. One of those moments..."hey if it is $60 bucks no brainer" but like I said uggghhh.

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