1988 C4 AC compressor cycling on and off
08-05-2017, 06:58 AM
#1
Drifting
Thread Starter
1988 C4 AC compressor cycling on and off
The first thing I did was good up a recharge kit from auto part store. The gauge came back in the normal range. I squeezed the trigger once and the readings fluttered and read normal range. The compressor cycles again and again. I changed the ac cycle switch and no change at all. The fan only works on low and medium. I changed the fan module. It is the manual hvac.
08-05-2017, 01:57 PM
#2
Melting Slicks
The first thing I did was good up a recharge kit from auto part store. The gauge came back in the normal range. I squeezed the trigger once and the readings fluttered and read normal range. The compressor cycles again and again. I changed the ac cycle switch and no change at all. The fan only works on low and medium. I changed the fan module. It is the manual hvac.
You Really Need a Gauge set. To Help show your Low/High side Readings. Your condition could be as Easy as a Low or High Pressure Switches are having problems or a clogged Orifice or even deeper problems
08-13-2017, 11:12 AM
#3
Drifting
Thread Starter
I am going to replace the compressor. New they are over $400 but I found rebuild's for $110. The condenser is more expensive being a one year only part. I would hate to take the chance on metal deposits damaging the replacement compressor.
I took the HVAC fan relay connection off to inspect the relay. It shows signs of damage from heat inside and plug and the connection on the car needs replaced. Napa wants $70 Autozone $60. Various sellers on eBay want over $40 until I found one for $23 shipped. I hope this will remedy my fan speed problem. I am debating having the freon drained and removing the compressor, condenser, and collector myself rather than pay for the labor. I've never removed a compressor. I know there is oil in the compressor but the procedure to install it is something I need to figure out. Is it worth paying someone?
I took the HVAC fan relay connection off to inspect the relay. It shows signs of damage from heat inside and plug and the connection on the car needs replaced. Napa wants $70 Autozone $60. Various sellers on eBay want over $40 until I found one for $23 shipped. I hope this will remedy my fan speed problem. I am debating having the freon drained and removing the compressor, condenser, and collector myself rather than pay for the labor. I've never removed a compressor. I know there is oil in the compressor but the procedure to install it is something I need to figure out. Is it worth paying someone?
08-13-2017, 08:56 PM
#5
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The pure mechanical end of swapping a compressor is easy, but if you still have R12 in your system I would be careful who you take it to. Many shops will not touch R12 cars because they need dedicated equipment to properly handle the R12. Get a set of manifold gauges and read the Hi/Lo pressures and get back to us.
08-14-2017, 07:13 AM
#7
Greetings,
....I too have an 88. I was going to ask if you changed out the refrigerant but, I see that it has been changed out to "134". Low refrigerant will cause a "short-cycle" and other things will also (low refrigerant, defective high or low pressure switch, etc).
.....You very well could have a bad low pressure switch which is located right in front of the evaporator at the firewall and that IS adjustable. A friend of mine had same problem.....
.....I would start off by trying to look for a visual leak (usually an oil stain which dirt will collect to) at all the hose, orifice tube, evaporator and condenser locations/connections as well as the front and back of compressor for leaks at seals or clutch area....
I you have access to a electronic leak detector, engage ac and fan on "low" and place probe in each of the vents to determine if you have an evaporator leak (can be used at all joints and fittings on items/areas mentioned above.
My 88 has an evaporator leak that I am waiting for temps to cool off here in Florida to attack and remove the evaporator where leak is.
Reference material should you need it:
https://www.corvetteforum.com/forums...r-removal.html
....I too have an 88. I was going to ask if you changed out the refrigerant but, I see that it has been changed out to "134". Low refrigerant will cause a "short-cycle" and other things will also (low refrigerant, defective high or low pressure switch, etc).
.....You very well could have a bad low pressure switch which is located right in front of the evaporator at the firewall and that IS adjustable. A friend of mine had same problem.....
.....I would start off by trying to look for a visual leak (usually an oil stain which dirt will collect to) at all the hose, orifice tube, evaporator and condenser locations/connections as well as the front and back of compressor for leaks at seals or clutch area....
I you have access to a electronic leak detector, engage ac and fan on "low" and place probe in each of the vents to determine if you have an evaporator leak (can be used at all joints and fittings on items/areas mentioned above.
My 88 has an evaporator leak that I am waiting for temps to cool off here in Florida to attack and remove the evaporator where leak is.
Reference material should you need it:
https://www.corvetteforum.com/forums...r-removal.html
Last edited by Da Mail Man; 08-14-2017 at 07:20 AM.
08-14-2017, 07:32 AM
#8
Drifting
Thread Starter
The pure mechanical end of swapping a compressor is easy, but if you still have R12 in your system I would be careful who you take it to. Many shops will not touch R12 cars because they need dedicated equipment to properly handle the R12. Get a set of manifold gauges and read the Hi/Lo pressures and get back to us.
08-14-2017, 07:35 AM
#9
Fan speed is either a bad fan motor, fan switch, or blower module located in engine compartment and is a 15 min change out (I had a bad one too).
Last edited by Da Mail Man; 08-14-2017 at 08:10 AM.
08-14-2017, 07:36 AM
#10
Drifting
Thread Starter
Greetings,
....I too have an 88. I was going to ask if you changed out the refrigerant but, I see that it has been changed out to "134". Low refrigerant will cause a "short-cycle" and other things will also (low refrigerant, defective high or low pressure switch, etc).
.....You very well could have a bad low pressure switch which is located right in front of the evaporator at the firewall and that IS adjustable. A friend of mine had same problem.....
.....I would start off by trying to look for a visual leak (usually an oil stain which dirt will collect to) at all the hose, orifice tube, evaporator and condenser locations/connections as well as the front and back of compressor for leaks at seals or clutch area....
I you have access to a electronic leak detector, engage ac and fan on "low" and place probe in each of the vents to determine if you have an evaporator leak (can be used at all joints and fittings on items/areas mentioned above.
My 88 has an evaporator leak that I am waiting for temps to cool off here in Florida to attack and remove the evaporator where leak is.
Reference material should you need it:
https://www.corvetteforum.com/forums...r-removal.html
....I too have an 88. I was going to ask if you changed out the refrigerant but, I see that it has been changed out to "134". Low refrigerant will cause a "short-cycle" and other things will also (low refrigerant, defective high or low pressure switch, etc).
.....You very well could have a bad low pressure switch which is located right in front of the evaporator at the firewall and that IS adjustable. A friend of mine had same problem.....
.....I would start off by trying to look for a visual leak (usually an oil stain which dirt will collect to) at all the hose, orifice tube, evaporator and condenser locations/connections as well as the front and back of compressor for leaks at seals or clutch area....
I you have access to a electronic leak detector, engage ac and fan on "low" and place probe in each of the vents to determine if you have an evaporator leak (can be used at all joints and fittings on items/areas mentioned above.
My 88 has an evaporator leak that I am waiting for temps to cool off here in Florida to attack and remove the evaporator where leak is.
Reference material should you need it:
https://www.corvetteforum.com/forums...r-removal.html
08-14-2017, 07:51 AM
#11
You could purchase a set of ac gauges off ebay and use an on-line pressure temperature chart to adjust charge.....I know they have them for "12" and other refrigerants. (Pict of blower module attached - not mine but, found in forum).
Last edited by Da Mail Man; 08-14-2017 at 08:45 AM.
08-14-2017, 08:21 AM
#12
08-14-2017, 08:28 AM
#13
A few picts of ac recovery machine and yellow recovery cylinder used to recover R-12. I wanted to change my orifice tube and that requires me to reclaim refrigerant and place system in a vacuum to recharge. Hummm, they didn't attach!...let me try again below.
Last edited by Da Mail Man; 08-14-2017 at 08:30 AM.