Air Con not working help please

[janker]

Hi everybody
I have a Rover 75 2.0 litre Diesel with no aircon for a few years now ,just decided after this good spell of weather to look into it .
Could someone give me some starting points to check please,i know it used to work but not for a few years.
Ive had the engine running with temp down to 16.c manually and tried auto but no joy.
Ive been trying to read up about it but struggling,Ive looked at the fan through the grill and it isnt moving but im not getting any overheating problems always at correct halfway mark.
Any tips to help would be appreciated,ive also looked in fuse box but nothing looks burnt or melted.
The aircon rad looks in good condition also the pump but im not sure wher to start testing.
many thanks for reading julian.

[RPWC]

When you switch the aircon on is the heater fan switched on!? Most common problem with aircon systems , is the refrigerant gas becomes stale, and needs replacing. This can be done at any garage that does aircon recharging,it should cost around £50. But if the low speed fan isnt working, then it could need the resistor replacing. There is plenty of information on the forum about it, forum trader Jules does an upgraded one, and if you're handy with a soldering iron,you can fit it yourself..

[Jules]

General points we carry out

Order of events is:

Recover old gas (if applicable)

Fit new condenser and pipes (if required)

Pressure test with Nitrogen to 8BAR.
Check for leaks while front of car still off especially around disturbed unions.

VAC down to 300-500 microns or at least (-1 bar) for 30 mins to an hour minimum to extract moisture and air

Add up to 100ml PAG46 oil (depending on how much is in the system)

Charge with 450g R134a
Wait 5mins for gas to equalise.

Start engine check low and high pressures are within spec and cooling fan for correct operation on all speeds

Also most importantly we check the temp of the LP & HP pipes during operation.

HP is generally no higher than 10C above ambient (if condenser is in good condition and working efficiently)
LP temp should get down to +4C within 1 minute (if compressor is good)


Jules


If cooling fan isn't working do not use the AC until fixed or select ECON (economy) below 30 mph until fan fixed.

There must be sufficient gas in the system to trigger the trinary pressure switch which in turn switches relay 7 (fuse box) via the command from the ATC unit.

Relay 7 then energises the compressor clutch and pressure differential occurs and hence evaporation

[janker]

Originally Posted by RPWC

When you switch the aircon on is the heater fan switched on!? Most common problem with aircon systems , is the refrigerant gas becomes stale, and needs replacing. This can be done at any garage that does aircon recharging,it should cost around £50. But if the low speed fan isnt working, then it could need the resistor replacing. There is plenty of information on the forum about it, forum trader Jules does an upgraded one, and if you're handy with a soldering iron,you can fit it yourself..

Hi Rich
thankyou for your response,Im not sure as the fan is running fastest speed to blow air into car and if i drop the temp to 16.c it doesnt get cold.
I cant see the fan running at the front of the car so maybe the low speed fan is not working and i need a replacement resistor from Jules,but how do i run some checks to see what is my problem ?

many thanks for your help appreciated julian

[Jules]

Check the middle of the compressor clutch is turning for starters.

Seen from above with torch into engine bay.
Compressor is the lowest pulley forward of the crank pulley

[janker]

Originally Posted by Jules

General points we carry out

Order of events is:

Recover old gas (if applicable)

Fit new condenser and pipes (if required)

Pressure test with Nitrogen to 8BAR.
Check for leaks while front of car still off especially around disturbed unions.

VAC down to 300-500 microns or at least (-1 bar) for 30 mins to an hour minimum to extract moisture and air

Add up to 100ml PAG46 oil (depending on how much is in the system)

Charge with 450g R134a
Wait 5mins for gas to equalise.

Start engine check low and high pressures are within spec and cooling fan for correct operation on all speeds

Also most importantly we check the temp of the LP & HP pipes during operation.

HP is generally no higher than 10C above ambient (if condenser is in good condition and working efficiently)
LP temp should get down to +4C within 1 minute (if compressor is good)


Jules


If cooling fan isn't working do not use the AC until fixed or select ECON (economy) below 30 mph until fan fixed.

There must be sufficient gas in the system to trigger the trinary pressure switch which in turn switches relay 7 (fuse box) via the command from the ATC unit.

Relay 7 then energises the compressor clutch and pressure differential occurs and hence evaporation

Many thanks Jules for your help and warning ,Noted, Im sure im going to be ordering something from you soon.
I just wanted to check if before having it gassed i wasnt missing something i could do myself.
many thanks Jules.

[Stevie25]

Originally Posted by Jules

General points we carry out

Order of events is:

Recover old gas (if applicable)

Fit new condenser and pipes (if required)

Pressure test with Nitrogen to 8BAR.
Check for leaks while front of car still off especially around disturbed unions.

VAC down to 300-500 microns or at least (-1 bar) for 30 mins to an hour minimum to extract moisture and air

Add up to 100ml PAG46 oil (depending on how much is in the system)

Charge with 450g R134a
Wait 5mins for gas to equalise.

Start engine check low and high pressures are within spec and cooling fan for correct operation on all speeds

Also most importantly we check the temp of the LP & HP pipes during operation.

HP is generally no higher than 10C above ambient (if condenser is in good condition and working efficiently)
LP temp should get down to +4C within 1 minute (if compressor is good)


Jules


If cooling fan isn't working do not use the AC until fixed or select ECON (economy) below 30 mph until fan fixed.

There must be sufficient gas in the system to trigger the trinary pressure switch which in turn switches relay 7 (fuse box) via the command from the ATC unit.

Relay 7 then energises the compressor clutch and pressure differential occurs and hence evaporation

Jules, perhaps you could advise?
My aircon works well on my diesel - especially since I purchased your fan upgrade.
However, it does suffer from the 'stale smell' during and after use.
Is there an easy DIY way to cure this?

[bigblue75]

Recently applied a foam antibacterial spray into the evaporator matrix housing https://the75andztclub.co.uk/forum/s...d.php?t=194849 and now have a fresh smelling car when air con is not in economy mode. Unfortunately, when in economy mode the car has an unusual smell through the vents- and more noticeably through the one for demisting.
Checked plenum (replaced pollen filter eight months ago- and have a carbon activated one on order to replace that one), anybody have any idea on what may be causing the odour when not using the air con?

[Jules]

Possibly your smelly feet 😀

Sorry couldn't resist !!

[Bogbrush82]

Originally Posted by bigblue75

Recently applied a foam antibacterial spray into the evaporator matrix housing https://the75andztclub.co.uk/forum/s...d.php?t=194849 and now have a fresh smelling car when air con is not in economy mode. Unfortunately, when in economy mode the car has an unusual smell through the vents- and more noticeably through the one for demisting.
Checked plenum (replaced pollen filter eight months ago- and have a carbon activated one on order to replace that one), anybody have any idea on what may be causing the odour when not using the air con?

Could still be the pollen filter?