LM7 swap a/c issues
Thread Starter
Teching In
Joined: Jul 2016
Posts: 13
Likes: 0
From: Dallas, TX
LM7 swap a/c issues I swapped a 2004 104k LM7 into my 1993 volvo 240.
The problem is that there is extremely high side pressure. 450+ psi when compressor is on. When A/C is off pressure equals out to 90psi on both low/high
Items that have been replaced:
-New dryer
-New orifice tube twice
Everything in the system has been flushed and blown out with compressed filtered air
New o-rings all around
Condenser, evaporator, dryer, 90% of lines are original to the 93 volvo
custom suction line from compressor to dryer
custom high pressure line from compressor to condenser
Car was not equipped with an expansion valve. NO Expansion Valve
Im using 10s17f compressor that came with the 2004 engine but this one is missing the valve on the back of the compressor. I believe it is a on/off cycle compressor. When we attempt to fill the system with r134a, the high side pressure goes up to 450-480 after about 12oz of r124a. Between 0oz and 12oz compressor cycles on/off as it should and pressure goes up to where you would assume it would be depending on temp 95º 40-50% humidity then high side drastically goes up. You would assume that the high pressure switch would kick in and shut the compressor off.
High pressure switch
on 270pis
off 412psi
At first maybe we though a blockage of some short but the system has been flushed before first attempt and before second attempt to fill system. Same results.
-Could the high pressure switch be faulty?
-is this a constant cycle compressor?
-is there still the possibility of there being a blockage some where else?
Any help or direction would be appreciated. Luckily r134a is $4.36 a 12oz can at walmart.
The problem is that there is extremely high side pressure. 450+ psi when compressor is on. When A/C is off pressure equals out to 90psi on both low/high
Items that have been replaced:
-New dryer
-New orifice tube twice
Everything in the system has been flushed and blown out with compressed filtered air
New o-rings all around
Condenser, evaporator, dryer, 90% of lines are original to the 93 volvo
custom suction line from compressor to dryer
custom high pressure line from compressor to condenser
Car was not equipped with an expansion valve. NO Expansion Valve
Im using 10s17f compressor that came with the 2004 engine but this one is missing the valve on the back of the compressor. I believe it is a on/off cycle compressor. When we attempt to fill the system with r134a, the high side pressure goes up to 450-480 after about 12oz of r124a. Between 0oz and 12oz compressor cycles on/off as it should and pressure goes up to where you would assume it would be depending on temp 95º 40-50% humidity then high side drastically goes up. You would assume that the high pressure switch would kick in and shut the compressor off.
High pressure switch
on 270pis
off 412psi
At first maybe we though a blockage of some short but the system has been flushed before first attempt and before second attempt to fill system. Same results.
-Could the high pressure switch be faulty?
-is this a constant cycle compressor?
-is there still the possibility of there being a blockage some where else?
Any help or direction would be appreciated. Luckily r134a is $4.36 a 12oz can at walmart.
Thread Starter
Teching In
Joined: Jul 2016
Posts: 13
Likes: 0
From: Dallas, TX
I would think not having enough flow over the condenser or not a big enough condenser could cause it. Have you tried running a garden hose over the condenser to see if its the problem? Also, its really hard to flush some components, so you could still have a blockage.
Thread Starter
Teching In
Joined: Jul 2016
Posts: 13
Likes: 0
From: Dallas, TX
Running water over was an idea from another local volvo guy. I forgot to do that and blockage is still on the list. The Pass through condenser that was a one year deal on the 93's are NLA but I have found as close to same size universal Im going to throw in and see.
Keep the ideas coming. A/C systems is still something I'm learning about. Ive mastered everything else like sticking a v8 into a brick.
Keep the ideas coming. A/C systems is still something I'm learning about. Ive mastered everything else like sticking a v8 into a brick.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
Having too little air flow will make the pressure spike, but those pressures seem too high for insufficient air flow to be the only issue. Do you have any idea what size orifice tube the Volvo uses or what the displacement of the stock compressor was?
Thread Starter
Teching In
Joined: Jul 2016
Posts: 13
Likes: 0
From: Dallas, TX
Nope. Im not even sure.
Stock compressor is Sanden DKS15BH
The orifice tube interchangeability is:
AUDI A4 2001-2005
AUDI A6 1998-2005
AUDI A8 1999-2012
AUDI S4 2001-2002
AUDI S6 1997
AUDI S8 2007-2010
BUICK LESABRE 2000-2004
CHEVROLET ASTRO 2002-2005
CHEVROLET CLASSIC 2004-2005
CHEVROLET MALIBU 1997-2006
GMC SAFARI 2002-2005
OLDSMOBILE ALERO 1999-2004
OLDSMOBILE CUTLASS 1997-1999
PONTIAC BONNEVILLE 2000-2005
PONTIAC GRAND AM 1999-2005
VOLKSWAGEN PASSAT 1999-2005
VOLKSWAGEN PHAETON 2004-2006
VOLVO 240 1991-1993
VOLVO 740 1985-1992
VOLVO 760 1983-1990
VOLVO 780 1987-1991
VOLVO 850 1993-1997
VOLVO 940 1991-1992
VOLVO 960 1992-1997
VOLVO C30 2008-2013
VOLVO C70 2000-2012
VOLVO S40 2005-2011
VOLVO S70 2000
VOLVO V50 2005-2011
VOLVO V70 1998-1999
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TECH Regular
Joined: Sep 2007
Posts: 443
Likes: 3
From: Kansas City, MO
What are the high and low side pressures? Usually if the high side and low side is high there is a lack of airflow (heat being removed) through the condenser. Might need more fan or make sure the condenser and radiator are properly shrouded.
