|
| | |
|
|
glennst
User
Aug 23, 2024, 8:25 AM
Post #1 of 30
(2609 views)
|
|
Rear Evaporator Flush
|
Sign In
|
|
2004 Chevy Tahoe LT
5.3Z 2WD
with Rear AC
Has anyone ever flushed their rear evaporator. I am working a compressor / accumulator / condenser swap and I flushed the front evaporator and it was easy. Flush flowed easily, air pressure flowed easily. No problem.
I went to flush my rear evaporator also because I purchased the Denso ND-8 oil and want to get as much PAG 46 oil out of the system and load with exact amount of NG 8. When I placed air hose on the rigid liquid line going into firewall towards rear evaporator it acts like it is clogged. Minimal air comes back thru any other lines. I assume the return on this is the insulated line coming back from firewall going to the splitter on the suction hose because I can detect a very slight amount of air there. I am only using air at this time but now am afraid to use any liquid flush.
QUESTION? Has anyone ever flushed your rear evaporator and if so was it easy, or did it appear very restricted?
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 23, 2024, 12:13 PM
Post #2 of 30
(2601 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
It's not clogged. You're blowing through the rear expansion valve.
Remember, evaps are not serpentine construction. Just because you can blow through one doesn't mean you are blowing through all of it.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
|
|
| |
|
|
glennst
User
Aug 23, 2024, 12:48 PM
Post #3 of 30
(2596 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Thanks Hammer Time
I did remove rear lines from rear evap. Behind back tire near the exhaust and the lines are clear. So as you stated its inside the evaporator.
That said I thought my system did not have an expansion valve since I have an accumulator and orifice? So does all rear evap use an expansion valve? Any chance I damaged the valve by blowing pressurized air (90 psi) through it?
glennst
(This post was edited by glennst on Aug 23, 2024, 1:16 PM)
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 23, 2024, 1:26 PM
Post #4 of 30
(2590 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Yes, it uses an orifice tube for the front and an expansion valve for the rear.
I can't know if you damaged it or not but since you have to remove it to finish flushing, you should just replace it while it's off. They aren't that expensive.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
|
|
| |
|
|
glennst
User
Aug 23, 2024, 1:50 PM
Post #5 of 30
(2583 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
HT it looks like a complicated ordeal to remove the rear evaporator. If I did not see any oil dripping from
the rear evap (ports are facing toward ground) should i be ok to proceed with vacuum pump testing? If it holds vacuum should i be ok?
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 23, 2024, 1:58 PM
Post #6 of 30
(2582 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
That won't tell you if the exp valve is stuck or not. It will just tell you if there are any leaks.
The chances are low that the valve is damaged from that so I would just go ahead and charge the system after checking for leaks and if the rear is cold, you're good to go.
I believe you have to remove the rear side panel inside to access the evap. It's not a real big deal, mostly trim panels.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
|
|
| |
|
|
glennst
User
Aug 23, 2024, 2:27 PM
Post #7 of 30
(2578 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Thanks….
glennst
|
|
| |
|
|
glennst
User
Aug 25, 2024, 10:12 AM
Post #8 of 30
(2407 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Has anyone ever experience this..?
Please help.
Summary - Poor cooling at idle. Gauges read Low=60 and High=165 at 85-90 ambient. Should be 45 and 225 ish. All info available could not identify anything definitive and suggested a weak compressor. Compressor is 20 years old so decided to replace it. Info suggests when replacing compressor to replace the accumulator also. I recovered around 5 oz of oil from those 2 items. I bought exact model compressor (Denso 471-0316). It indicated for warranty I must use ND-8 oil so ok I am this far so i decided to flush the front evaporator and clean it. That went great. But I read you cannot flush a condenser so WTH I am this far so replaced it with a new ACDelco 15-63667 condensor. Hey only thing left up front are the lines so I replaced all lines (discharge, suction, liquid-rigid).
I removed and flushed the lines going back to rear evaporator and left off 2 days to allow any oil to drip out of rear evaporator. I blew air into the rear evap and some air passed but per feedback the TXV expansion valve wont let much air pass so I accepted as good.
95% new system. Clean. I loaded ND-8 oil into system. Compressor came with 2.5oz, I added 1 oz to condenser input, 1 oz to each evaporator input, and 2 oz to accumulator. total = 7.5 oz.
Pumped id down for 3 hours. -29 solid. Let sit overnight and no leaks. -29 solid.
OK here is where my perfect world turned upside down. Using 12 oz cans and SureBilt can tap dispenser from Autozone I attached can, bled air, cranked car and turned on AC, opened low side, and it pulled in about 6 oz and compressor kicked on but then it stopped pulling freon. Clutch engaged and turning but nothing. I shook can, turned it between 12-3 oclock, turned it upside down. open and closed the tap, etc. nothing. i closed tap (wide open so can self sealed) and put on a new can. nothing. I went and purchased a new tap dispensor but nada.
SO WTH? Why will my system not pull freon and charge?
It almost back to the same problem i started with?
My gauges are per pic (engine off) both around 90 psi which I guess are good static readings. But i cannot get it to charge.
oops not allowed to attach pics yet. i am new to forum.
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 25, 2024, 10:30 AM
Post #9 of 30
(2402 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
There is no restriction to attaching pics to anyone. There are occasionally some issues with the site's imaging software. I have been using an external site myself.
On your charging problem you have to remember refrigerant will flow from higher pressure to lower pressure. Since your low side reading is a bit high, it's getting too close to the can pressure. What you can do is get a container of hot water and submerge the charging can into it. That will make it charge faster.
As far as your pressures are concerned, turn off the rear AC while charging. It is normal for pressures and temps to be higher when both systems are running because you are trying to cool 2 evaporators with one compressor. This is the same compressor used on a single system so if you are running both front and rear at the same time you will get higher suction pressure and higher front vent temp.
You do have to run it for a while after it's fully charged to get all the oil circulated and the system stabilized to see max temp.
The other issue you are probably dealing with is that a lot of the foam sealer between the doors has deteriorated allowing warm air to mix with the cold air due to the air of the vehicle.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Aug 25, 2024, 10:31 AM)
|
|
| |
|
|
glennst
User
Aug 25, 2024, 10:55 AM
Post #10 of 30
(2394 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
I pride myself on being thorough but you got me.
1. I have the rear AC running.
2. The guy who evacuated my system told me to put the freon can in hot water if i had problems and I completely forgot about it.
Going to eat lunch and try it again. Fingers crossed.
glennst
|
|
| |
|
|
glennst
User
Aug 25, 2024, 12:10 PM
Post #11 of 30
(2375 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
I tried to upload photo but it asks me to enter email and password. When I do it fails. When I choose forgot password it asks for my email. When i enter email it tells me my email is not in system. However I can log in and add comments. When i joined it informed me I would not be able to add photos until I had posted 7 times.
Ok here is latest on freon load. My rear AC was off but to be certain I unplugged the RR HVAC fuse. I placed freon can in hot tap water and it appeared to load more freon as high side pressure increased to 130 psi, BUT the low side pressure increased to 350 psi and has never dropped. I shut engine off.
any advice?
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 25, 2024, 12:40 PM
Post #12 of 30
(2368 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
I believe you have to register separately for the image software.
I think you have those pressures backwards. 350 is way too high. You either have no cooling fan or it's way overcharged.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
|
|
| |
|
|
glennst
User
Aug 25, 2024, 1:03 PM
Post #13 of 30
(2354 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Unfortunately I dont have it backwards.
Low side at 350 psi.
I signed up for pics but now cant load any above 500K size. My mobile wont take less than 1M.
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 25, 2024, 1:07 PM
Post #14 of 30
(2352 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
No, that's not possible. The low side cannot be higher than the high side. The compressor sucks from one side and pushes out the other. You can't have higher pressure on the suction side.
Here's a dumb question.......... are you sure you removed the shipping plugs from the condenser?
You're going to have to use some edit software to reduce the size of your pics.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Aug 25, 2024, 1:08 PM)
|
|
| |
|
|
glennst
User
Aug 25, 2024, 2:39 PM
Post #15 of 30
(2330 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
I have had crazy things happen to me. I have the photo. I will try to edit the jpeg but cannot today. Do you have an email I can send pic i have ?
Just curious when i added 3 oz of oil to accumulator i just poured it into the port where the suction line connects going back to the compressor. Was that correct?
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 25, 2024, 2:43 PM
Post #16 of 30
(2329 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
It was a little heavy on the amount for the accumulator but it won't effect anything.
You can try this place for images
https://postimages.org/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
|
|
| |
|
|
glennst
User
Aug 25, 2024, 3:00 PM
Post #17 of 30
(2323 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
ok tried to load the pics. Normal, and then 480x680?
Also a found an article where a guy could not load freon on a silverado until he swapped out his fan clutch (not cooling good enough)? I will replace it tomorrow since its also 20 years old.
I dont mind buying parts and i may also just teplace the rear evap and expansion
valve also. parts cannon maybe but at least i am getting things new after 20 years and can end up with some spares if good.
Found another article where guy loaded freon on high side with can upside down (liquid)?
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 25, 2024, 3:26 PM
Post #18 of 30
(2316 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
That is not a normal fan clutch. It's pulse width modulated by the PCM so it's pretty expensive.
Don't pump liquid. You can crash your new compressor.
You can't load high side with the engine running and if you do it with the engine off it will stop when the pressure equalizes which will be less than one can.
If you try pumping into the high side with the engine running the can will explode in your hand.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Aug 25, 2024, 3:29 PM)
|
|
| |
|
|
glennst
User
Aug 26, 2024, 5:40 AM
Post #19 of 30
(2188 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Yea I dont have the experience or balls to tty high side.
I took today off to try once more before I take it to a professional. I just dont want to feel like a failure.
I found the fan clutch for my vehicle at autozone for $80.
Duralast Fan Clutch 922786. Also a new fan blade for $60.
I hate being a parts cannon but my original parts are 20 years old so why not.
I have an engine light on and will read it this morning after coffee. Probably an ac pressure sensor code.
Could a bad expansion valve on the reaf evaporator cause my problem?
Also i purchased this line (AutoZone part 55942) and installed it without looking to see if the orifice tube was in it or wrapped in plastic, etc. Online it states it comes with the orifice tube so i just trusted but did not verify. Going to look at this this morning also.
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 26, 2024, 5:50 AM
Post #20 of 30
(2183 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Forget about the high side charging idea. It can't be done without a recovery/charging machine.
It should be pretty easy to determine if the fan is pulling air or not. I am not a fan of the parts cannon, even if you can afford it, you can create new problems in the process. You should have a reason for everything you do.
Letting a professional look at this may be the best path at this point. It's starting to get dangerous and risking damaging the new parts you just bought.
Like I told you earlier, cracking that valve open to those high pressures will allow that pressure back into the can and explode it causing serious injury.
No, the rear exp valve won't effect anything but the rear air temp.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Aug 26, 2024, 5:58 AM)
|
|
| |
|
|
glennst
User
Aug 26, 2024, 2:54 PM
Post #21 of 30
(2109 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Well guess what I found today. In one way its embarrassing, yet another it makes me very angry.
There is no orifice tube in the line. I purchased the new line from Autozone and their website has “ Four Seasons A/C Hose Assembly with Orifice Tube 55942”. It came in a large clear plastic zip bad with handle. One piece and no separate tube. Thus I trusted it was already installed.
one moment please.. “@&$(:/((&75;,?&&??(;/-2;)$. ihbhfdxc vhbjoiygfxxcc “…..
So now I could have damaged my new compressor or evaps or new condensor, etc all because of trusting autozone.
Ok so would no orifice tube explain my experience?
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 26, 2024, 3:00 PM
Post #22 of 30
(2108 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Lack of a tube will only cause no cold air. It's high pressure on the discharge side that does the damage.
Make sure you are charging it with the exact specified weight of refrigerant. Otherwise the pressures mean nothing. This doesn't explain the high discharge pressure.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
|
|
| |
|
|
glennst
User
Aug 27, 2024, 7:06 AM
Post #23 of 30
(1964 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Hammer
I read somewhere that a clogged condenser could cause high pressure on low side. My condenser is brand new but before I vacuum system down again would it be a good idea to blow air in it to conform its clear?
glennst
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Aug 27, 2024, 8:06 AM
Post #24 of 30
(1955 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
That would be a waste of air. Don't believe everything you read on the Internet.
Current condensers are no longer serpentine type. They are bypass type meaning they have one chamber that feeds all the tubes simultaneously, therefore even if all tubes but one are blocked solid, the air will still pass through the one tube meaning it's not flushable.
You need to look hard at the fan before even considering a condenser. When the pressure rises the PCM will bring the fan speed up and the pressures will drop.
Everything starts with a correct WEIGHED charge. Make sure you installed the tube in the right direction also. The screen side goes facing the condenser.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
|
|
| |
|
|
glennst
User
Aug 27, 2024, 8:36 AM
Post #25 of 30
(1947 views)
|
|
Re: Rear Evaporator Flush
|
Sign In
|
|
Thanks Hammer that makes sense.
BTW yesterday I installed a new clutch and fan.
Today I am installing the orifice and vacuum pumping it down. I will let it run for several hours to ensure it’s good because here in Houston we have high humidity.
I might try to load it tonight but cant tomorrow. Is it safe to leave it under vacuum until Thursday?
glennst
|
|
| |
|
Auto Repair Home
SEARCH
WHO'S 
LOG 
Toro 1644 Hxl won't start
Mercedes Benz keeps getting Unaligned !
Codes say Drive by wire throttle body but tests seem to conflict
1
