AC air flow information for S1 XJ
#1
10-26-2017, 06:16 PM
AC air flow information for S1 XJ
My great AC shop has been trying to find the source of the abnormal high side vent temp with the AC on... normally I see 39-40F at the side vents with the
AC fans on Low speed...they are about 5 degrees higher when the new GM fans are on High speed. Now they are only producing 53F temps... all else has been confirmed to be working properly... thermostat cycles off/on properly. The pressures on the charging gauges are proper and comparable to past figure.
Nothing appears to be wrong..I am looking for technical information that might have been in a Jag Shop Manual.. the air flow direction using inside/outside// that shows air flow and hopefully has some flow speeds?
The '71 S1 XJ is the first year Jag had all the AC stuff inside the car.. no rear evaporator etc. and two fans in the firewall.
Is there any information/knowledge of why there is only a thin piece of foam wrapped around the heater matrix/core between it and the coils in the evaporator? I have attached photos of the two with the heater matrix out in one photo and in place in another. The two side vents are just for information and rear of the evaporator is shown to provide information about the coils.
AC fans on Low speed...they are about 5 degrees higher when the new GM fans are on High speed. Now they are only producing 53F temps... all else has been confirmed to be working properly... thermostat cycles off/on properly. The pressures on the charging gauges are proper and comparable to past figure.
Nothing appears to be wrong..I am looking for technical information that might have been in a Jag Shop Manual.. the air flow direction using inside/outside// that shows air flow and hopefully has some flow speeds?
The '71 S1 XJ is the first year Jag had all the AC stuff inside the car.. no rear evaporator etc. and two fans in the firewall.
Is there any information/knowledge of why there is only a thin piece of foam wrapped around the heater matrix/core between it and the coils in the evaporator? I have attached photos of the two with the heater matrix out in one photo and in place in another. The two side vents are just for information and rear of the evaporator is shown to provide information about the coils.
#2
10-27-2017, 08:28 AM
Need for information that may be in Jag Shop Manual?
Stock there are no center vents on a S1, just the two side “fascia” vents… I have added two, the source for one is from the bottom of the evaporator where a hole was already. The other source is from the the right hand tube that used to feed the rear passengers heat and cold. The air is even on both sides and the temps the same 53F after cooling down the air.
The heater functions perfectly… (water flow has been confirmed off by clamping of the feed line) but heat is not needed much in So Cal. AC is used about 300 days per year. They are separate systems on a S1… no climate control blending is done. My questions concerns the closeness of the heater matrix and the coils in the evaporator with only a thin piece of foam being wrapped around the heater coils.
The expansion valve is a new one, setup with R134 - adapted to the S1 flare on the right side and the capillary tube extended by cutting and adding more tubing to the bulb on the left (drivers) side. It is functioning properly.
I am afraid some of the insulation from the two fans area have dropped down and are blocking the screens around the coil in the evaporator. Any proper examination involves removal of the center console and maybe much more… I did this about 10-15 years ago when the heater matrix was leaking. The pictures show how far down the removal is to take out the evaporator.
I am hoping someone has a S1 Jaguar Shop Service Manual and can look for any information about the PATH of the air that flows through the evaporator. Plus, is there any flow information in amounts that pass through the evaporator in a period of time and how is that measured? The shop says some manufacturers give that info for troubleshooting. Do the manual talk about the heater matrix/AC in any manner? I only have aftermarket manuals and the Jaguar CD parts and service manual. Something has changed recently with no work being done to stop the very cold air of the past and only
allow the air to cool to 53F…38-40F is much better and desirable. The volume of air at any of the vents has not changed.
All we know is the air flows from the top flap, either from the outside of the car or from the inside depending on how it is set. It then enters the evaporator and is pushed around the inside/coils and out the exits that are selected open. With more air speed, the air feels “cooler” on the faces of the occupants… but with the speed the air heats up… Coldest air by measurement is at minimum fan speed… this is normal AC stuff.
The only other suggestion I have had is the Jaguar Ranco thermostat… it does cycle off/on but may be doing this too early and not allowing the maximum amount of coolness to occur. It is possible the capillary tube has backed out of the coils or the thermostat is failing after only 46 years! This will be tested today by the shop…it is easily replaced as it is external to the evaporator and attaches to the front surround panel.
The heater functions perfectly… (water flow has been confirmed off by clamping of the feed line) but heat is not needed much in So Cal. AC is used about 300 days per year. They are separate systems on a S1… no climate control blending is done. My questions concerns the closeness of the heater matrix and the coils in the evaporator with only a thin piece of foam being wrapped around the heater coils.
The expansion valve is a new one, setup with R134 - adapted to the S1 flare on the right side and the capillary tube extended by cutting and adding more tubing to the bulb on the left (drivers) side. It is functioning properly.
I am afraid some of the insulation from the two fans area have dropped down and are blocking the screens around the coil in the evaporator. Any proper examination involves removal of the center console and maybe much more… I did this about 10-15 years ago when the heater matrix was leaking. The pictures show how far down the removal is to take out the evaporator.
I am hoping someone has a S1 Jaguar Shop Service Manual and can look for any information about the PATH of the air that flows through the evaporator. Plus, is there any flow information in amounts that pass through the evaporator in a period of time and how is that measured? The shop says some manufacturers give that info for troubleshooting. Do the manual talk about the heater matrix/AC in any manner? I only have aftermarket manuals and the Jaguar CD parts and service manual. Something has changed recently with no work being done to stop the very cold air of the past and only
allow the air to cool to 53F…38-40F is much better and desirable. The volume of air at any of the vents has not changed.
All we know is the air flows from the top flap, either from the outside of the car or from the inside depending on how it is set. It then enters the evaporator and is pushed around the inside/coils and out the exits that are selected open. With more air speed, the air feels “cooler” on the faces of the occupants… but with the speed the air heats up… Coldest air by measurement is at minimum fan speed… this is normal AC stuff.
The only other suggestion I have had is the Jaguar Ranco thermostat… it does cycle off/on but may be doing this too early and not allowing the maximum amount of coolness to occur. It is possible the capillary tube has backed out of the coils or the thermostat is failing after only 46 years! This will be tested today by the shop…it is easily replaced as it is external to the evaporator and attaches to the front surround panel.
#3
10-28-2017, 08:46 AM
Taking out the evaporator this weekend
The expansion valve was replaced again, this time with a modern valve and long capillaries - it is equivalent of the stock valve in size but setup for use with R134.
If interested, contact me for the shop address and phone number.
More close examination was made and a laser probe used to measure the temp of the floor of the car at the air flow area below the evaporator.. the hole used for the second vent tube in this car. The temp, with the car inside the shop and AC running on High speed, 83.5F.
The plan is for me to remove the evaporator and return the car to the shop with it out.. examine the whole area behind the unit and then put insulation EVERYWHERE in that area. We need to lower the firewall/floor temp in the
evaporator area and behind the stock Jag vent tubing.
If interested, contact me for the shop address and phone number.
More close examination was made and a laser probe used to measure the temp of the floor of the car at the air flow area below the evaporator.. the hole used for the second vent tube in this car. The temp, with the car inside the shop and AC running on High speed, 83.5F.
The plan is for me to remove the evaporator and return the car to the shop with it out.. examine the whole area behind the unit and then put insulation EVERYWHERE in that area. We need to lower the firewall/floor temp in the
evaporator area and behind the stock Jag vent tubing.
#4
10-29-2017, 12:56 PM
The expansion valve was replaced again, this time with a modern valve and long capillaries - it is equivalent of the stock valve in size but setup for use with R134.
If interested, contact me for the shop address and phone number.
More close examination was made and a laser probe used to measure the temp of the floor of the car at the air flow area below the evaporator.. the hole used for the second vent tube in this car. The temp, with the car inside the shop and AC running on High speed, 83.5F.
The plan is for me to remove the evaporator and return the car to the shop with it out.. examine the whole area behind the unit and then put insulation EVERYWHERE in that area. We need to lower the firewall/floor temp in the
evaporator area and behind the stock Jag vent tubing.
If interested, contact me for the shop address and phone number.
More close examination was made and a laser probe used to measure the temp of the floor of the car at the air flow area below the evaporator.. the hole used for the second vent tube in this car. The temp, with the car inside the shop and AC running on High speed, 83.5F.
The plan is for me to remove the evaporator and return the car to the shop with it out.. examine the whole area behind the unit and then put insulation EVERYWHERE in that area. We need to lower the firewall/floor temp in the
evaporator area and behind the stock Jag vent tubing.
#5
10-29-2017, 07:16 PM
Evaporator is out now... no apparent problems noted. Will put insulation on the flooring under the area and around the firewall high up so the vent tubing does not receive
any heat from the engine compartment. The rest of the car is already insulated.
The left hand side of the expansion valve currently has the stock pipe with the return hose to the compressor.. it will be changed to one with a screw on fitting for ease of servicing the system in the future.
I expect the thermostat will be replaced with another brand that is totally adjustable. That way we can control the start/stop temperature the compressor cycles at in the
future.
Removing the S1 evaporator is not a fun job. Took about 6 hours today and parts of the dash wood had already been removed prior to today. Doing the work myself will save me
a lot of shop hours of labor. It will be tested with coolant for any leaks.. but the system was holding the charge before, so this is only a precautionary testing.
any heat from the engine compartment. The rest of the car is already insulated.
The left hand side of the expansion valve currently has the stock pipe with the return hose to the compressor.. it will be changed to one with a screw on fitting for ease of servicing the system in the future.
I expect the thermostat will be replaced with another brand that is totally adjustable. That way we can control the start/stop temperature the compressor cycles at in the
future.
Removing the S1 evaporator is not a fun job. Took about 6 hours today and parts of the dash wood had already been removed prior to today. Doing the work myself will save me
a lot of shop hours of labor. It will be tested with coolant for any leaks.. but the system was holding the charge before, so this is only a precautionary testing.
#7
11-09-2017, 01:21 PM
Received the EZ-Kool heat insulation material and just installed it under the AC evaporator. Easy to cut and I used 3M spray on adhesive..just waiting for the glue to dry and then will start the evaporator reinstall. Put it on the sides and up to the bottom of the heater matrix and all the way down to the center support for the center console.
Should help lower the air temps in the evaporator that mounts in the empty space. Will only put enough back into place to drive the car to the shop. This time the AC will cool down properly or it is all coming out for modern Vintage Air stuff!
Should help lower the air temps in the evaporator that mounts in the empty space. Will only put enough back into place to drive the car to the shop. This time the AC will cool down properly or it is all coming out for modern Vintage Air stuff!
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#8
11-21-2017, 04:44 PM
Car is done, vent temps are 40F at ambient temps of 79F.. feels very comfortable now.
Using the new expansion valve (part number on the invoice that was NO CHARGE) with the number 18-2141, plus the insulation under the evaporator area has allowed the air temps to return to normal.
When I asked why it was a no charge repair, I was told "because he did not fix it properly last time".. great shop and people there with integrity.
Will start putting all the dash and interior stuff I removed for their access back on tomorrow... another day or so to get it all back in place 100%.
Just in time for our current heat wave for Thanksgiving.
Using the new expansion valve (part number on the invoice that was NO CHARGE) with the number 18-2141, plus the insulation under the evaporator area has allowed the air temps to return to normal.
When I asked why it was a no charge repair, I was told "because he did not fix it properly last time".. great shop and people there with integrity.
Will start putting all the dash and interior stuff I removed for their access back on tomorrow... another day or so to get it all back in place 100%.
Just in time for our current heat wave for Thanksgiving.
Last edited by Roger Mabry; 11-21-2017 at 04:49 PM.