Welcome to the world's #1 Volvo forum!

Volvo Fixes & Advice since 2001.

Login Register

Back Flushing

Help, Advice, Owners' Discussion and DIY Tutorials on all Volvo's "mid era" rear wheel drive Volvos.

1975 - 1993 240
1983 - 1992 740
1982 - 1991 760
1986 - 1991 780
1990 - 1998 940
1990 - 1998 960
1997 - 1998 V90/S90

Post Reply
waynegarbo
Posts: 74
Joined: Tue Dec 15, 2015 5:18 pm
Year and Model: 86' 740 non-turbo
Location: Fresno, Calif.
Has thanked: 2 times

Back Flushing

Post by waynegarbo »

I'm getting ready to flush the evaporator. Is it OK to back flush and leave the liquid line attached to do both at the same time?

User avatar
MoVolvos
Posts: 3041
Joined: Sun Jan 15, 2012 6:47 pm
Year and Model: 03S80T6~08C30T5
Location: NC
Has thanked: 65 times
Been thanked: 127 times

Post by MoVolvos »

waynegarbo wrote: Thu Oct 31, 2019 12:02 pm I'm getting ready to flush the evaporator. Is it OK to back flush and leave the liquid line attached to do both at the same time?
What occurred to the system so that you are only flushing the Evap and Liquid Line? This video shows flushing is insufficient for the Condenser which means it won't be good enough for the Evaporator either. The filter and dryer is suppose to pick up a few things but not a really contaminated system.

Blessings,

BKM


2003 S80 T6
2008 C30 T5 2.0 M66
1998 S70 T5 Prior
1989 240 Wagon Prior

waynegarbo
Posts: 74
Joined: Tue Dec 15, 2015 5:18 pm
Year and Model: 86' 740 non-turbo
Location: Fresno, Calif.
Has thanked: 2 times

Post by waynegarbo »

I am flushing the evaporator first to remove everything then I'm going to pressure test it with a hand vac. If the pressure test fails then I will not proceed any further. This is an old system that hasn't worked for probably 20yrs. I have seen Scotty's video but I don't believe it applies to my condenser because it's an older system with larger passages. I found 3 large shavings on the outside of my orifice tube, that tells me my condenser has large ports. When I did a dye charge, the high pressure never came up which coincides with the shavings from my compressor. The juries not out so I'll flush the condenser and pressure test it also if my evaporator passes. Then i'll flush the hoses. After I install the new compressor, orifice, and dryer, I plan on putting on two filters if I decide to stay with the old condenser. But right now I'm asking if I can leave the liquid line on when I flush the evaporator.

User avatar
MoVolvos
Posts: 3041
Joined: Sun Jan 15, 2012 6:47 pm
Year and Model: 03S80T6~08C30T5
Location: NC
Has thanked: 65 times
Been thanked: 127 times

Post by MoVolvos »

waynegarbo wrote: Fri Nov 01, 2019 2:46 pm
I have seen Scotty's video but I don't believe it applies to my condenser because it's an older system with larger passages... But right now I'm asking if I can leave the liquid line on when I flush the evaporator.
I know it's oversimplified but on car or off and which end do you intend to spray/flush from? How long is your liquid line?
-
https://www.autozone.com/images/MEDIA_P ... iagram.jpg
-
Auto AC System.png
Auto AC System.png (240.44 KiB) Viewed 360 times
Blessings,

BKM


2003 S80 T6
2008 C30 T5 2.0 M66
1998 S70 T5 Prior
1989 240 Wagon Prior

User avatar
MoVolvos
Posts: 3041
Joined: Sun Jan 15, 2012 6:47 pm
Year and Model: 03S80T6~08C30T5
Location: NC
Has thanked: 65 times
Been thanked: 127 times

Post by MoVolvos »

In thinking about this more, it would be best out of the car and back flush without the low pressure liquid line. Afterwards, I would forward flush the evaporator also.
Blessings,

BKM


2003 S80 T6
2008 C30 T5 2.0 M66
1998 S70 T5 Prior
1989 240 Wagon Prior

waynegarbo
Posts: 74
Joined: Tue Dec 15, 2015 5:18 pm
Year and Model: 86' 740 non-turbo
Location: Fresno, Calif.
Has thanked: 2 times

Post by waynegarbo »

I'll disconnect the liquid line and flush the evaporator left in the car because the evaporator is to much for me to remove. In fact if my evaporator fails the pressure test I've decided not to proceed with any other repairs or replacement.

waynegarbo
Posts: 74
Joined: Tue Dec 15, 2015 5:18 pm
Year and Model: 86' 740 non-turbo
Location: Fresno, Calif.
Has thanked: 2 times

Post by waynegarbo »

What's the best way to catch the contents coming out when I flush? Will air pressure blow it all over? Or will it flow out without a mess?

User avatar
MoVolvos
Posts: 3041
Joined: Sun Jan 15, 2012 6:47 pm
Year and Model: 03S80T6~08C30T5
Location: NC
Has thanked: 65 times
Been thanked: 127 times

Post by MoVolvos »

waynegarbo wrote: Tue Nov 05, 2019 10:30 am What's the best way to catch the contents coming out when I flush? Will air pressure blow it all over? Or will it flow out without a mess?
This might help with your work.
Blessings,

BKM


2003 S80 T6
2008 C30 T5 2.0 M66
1998 S70 T5 Prior
1989 240 Wagon Prior

waynegarbo
Posts: 74
Joined: Tue Dec 15, 2015 5:18 pm
Year and Model: 86' 740 non-turbo
Location: Fresno, Calif.
Has thanked: 2 times

Post by waynegarbo »

This guy left the liquid line as the drain for the solvent because he's going to change it. I'm going to do the math on changing everything and decide.

jimmy57
Posts: 6674
Joined: Fri Nov 12, 2010 9:25 am
Year and Model: 2004 V70R GT, et al
Location: Ponder Texas
Has thanked: 4 times
Been thanked: 279 times

Post by jimmy57 »

The orifice tube in the line next to strut housing needs to come out if it is not already open there. You can't flush it with orifice in place as that will restrict flow and catch all the debris that might be there.

Post Reply