Air Con Control

[vodkas]

Having problems with air con not being very good at all. Had it charged 3 times at work even though it is not leaking (vaccumed out incase it had been contaminated).

 

The temperature of the air coming out of the vents was varying from sligtly cool to warm with hissing noise (not leak) intermittently coming from evapourator.

 

Sussed out the cause. Condenser fan is not coming in and pressure on the HP side is rising to around 25 bar becoming very inefficent and causing the evapourator to hiss. When the cooling fans do eventually come in due to high engine temperature, the AC begins to work but only for a short time 'till the HP becomes too high again. The AC is not controlling the fans only the engine temp.

 

Question. Is there a HP switch to bring in/control the condenser/radiator fans and if so where is it. Also is there a sight glass or receiver on the system to show the charge. There are so many pipes and swiches on the V6 and the engine taking up all the engine bay that I cannot find anything.

 

thanks vods

[seatkid]

Whenever A/C is turned on, the cooling fan should come on (half speed). Sounds as if you have an electrical fault.

For all electrical faults, you need to post full details of year, model, and options such as A/C variant cc etc. as there as several wiring possibilties.

 

I'm guessing now - 1999 V6 - try fuse F28 (10A)

[vodkas]

Thanks Seakid for the promp reply.

 

The car is a 1998 v6 auto 4wd ghia-x if that helps. I have a haynes manual but it does not include my model.

 

There are two fans on the radiator one higher and to the middle and one lower towards the near side. Any idea what the difference is. Also there is a fan control module (looks like heavy duty relays) infront of the battery with two high ampage plugs feeding the fans and a smaller plug, probably the signal wires.

 

I cant be certain but I think I am getting a click out of it when the AC starts up but no fans coming on. I have checked the signal wires and one is live by the ignition but none of the others change status when AC comes on (stange because this would account for the click as it happens when AC starts). One becomes live when engine temp is too high.

 

I am checking the wires while the plug is off (4 wires) so maybe i am getting anomalies because it is not in circuit.

 

I have never noticed the fans running at half speed even last year when it seemed ok, could it be that one fan runs all the time and the other cuts in when engine is hot?

 

If they are duals speed as it shows for other models, do you know wher the resistors are hidden. It may be possible to hot wire one fan on slow speed.

 

A circuit diagram would help loads.

 

vods

[seatkid]

may or may not help

AC_with_ATC_Module_2_8i_CD_V6_1998.doc

[vodkas]

Thanks Seatkid

 

Found that the fan resistors for both fans had burnt out so only getting full fan speed when every thing was 'red' hot.

 

Created another problem now. Bypassed resistor on one fan to give constant cooling and everything looked great. Engine temp and AC looking good so went out for a few hours drive. Then whammy, AC compressor seized up pulley became hot and snapped pulley/fan belt. Had to call out RAC recovery (there goes my RAC no claims discount).

 

On checking the AC compressor when I got home, It is now free, little bits of burnt belt stuck to pulley and the centre of the nylock nut melted. I am wondering what caused it to seize up, could the compressor have frozen ?. Cant test it properly because I cant source a pulley belt as it is bank holiday.

 

Its just going bad to worse. Never mind, the fun of motering lol.

[ridway]

Vodkas

 

Sorry to here your tale of woe. I'd be very depressed by now.

From your description of events I think there are two possibilities.

First if the system has been charged 3 times then you could have lost a lot of refrigerent oil. This loss then causing a seizure of the compressor. Secondly, the lack of cooling has fooled you or the repairers to thinking there is a leak and thus re charging several times. If there isn't a leak then there would be far to much refrigerant in the system and "whammy" the compressor could find itself trying to compress a liquid.

 

In the latter case, too much refrigerent, you may get away without damage to the compressor, however as you point out the electric clutch might need attention. A lack of oil in the first case will probably be terminal, new compressor required.

I agree with the comments on the electrical system that there may be a fault affecting the fans. I don't envy your situation.

 

You need to firstly to somehow establish and repair the compressor, then evacuate and purge with dry nitrogen. Recharge with no more than 800 gram of R134a refrigerant and establish whether there is a leak. If necessary firstly leave charged with nitrogen overnight at around 12 bar to see if there is a fall in pressure before introducing the gas. Prior to this and especially after such a catastropic failure I would change the filter dryer and check the TEV on the evaporator is working correctly, as this could also give a high condensor pressure as you mentioned. Also do a visual check for leaks before charging. Signs of this are oily dirty patches on pipes associated with the aircon. I don't know about the V6 but the diesel gal is very prone to cracking aluminium pipes at the top of the condensor.

 

This sounds like a bad failure that will be hard to find the cure for cheaply but the car car sounds worth it. Hope this helps, best of luck with it.

 

Rich

[vodkas]

First thing is to get the car back on the road ASAP as i need it to get to work. Hopefully the pulley on the compressor will still be ok and i'll do without AC for now.

 

Since getting the car 20 months ago remote locking/unlocking broke, cruise control jacked in, cracked windscreen, cd player dead and now AC. OH well there is still plenty more to go t*ts up.

 

Best car I ever had MK1 ford escort, nothing on it to go wrong.

[seatkid]

:P Chuffing eck!! :D No wonder they call you vodkas, I'd be knocking them back like mad if I had your problems.... :P

 

Good luck fixing it!

 

Ridway, when I eventually change that leaking evaporator of mine this summer do you recommend the nitrogen purge? Would any garage that regasses A/C's do this or do I need to go to a specialist?

[Guest nimrod]

How longs it been left with out gas? you could be changing a lot more than just the evaporator! for starters the filter dryer will need replacing and possibly a few of the O rings where they may have dried out! the system will need to be emptied and left under vacuum for 2/3 hrs to make sure that all the moisture is removed from the system before its re gassed that alone is a specialist job!

plus the responsible thing to do is to have the system pumped dry befor you start work and not just discharge any gas still left in the system! the guy that did my heater matrix drained the system and re used the gas in order to cut the cost of the job!

[vodkas]

Display on climate control started flashing late last year. Connected it to a diagnostic computer and told me it was a pressure switch (the sytem was low on gas and showing an error).

 

Six weeks ago I got the system recharged but there was still a small amount of refrigerent in the system, not enough to trigger the pressure switch though. Had it checked for leaks and seems ok. The drop in refrigerent must be down to acceptable loss over its 6 year life.

 

Luckily for me the fridge engineers I work with have vac pumps, gauges etc and as much R134a as a very large factory needs. Just need 1 of them to know what they are doing.

[seatkid]

How longs it been left with out gas? you could be changing a lot more than just the evaporator!

In my case my A/C's been kaput for about a year now,after 18 months of repair attempts at the dealers. I got fed up giving wads of dosh to the Seat dealer

 

comments like "We're fairly certain we've fixed it, sir" eventually "we think its leaking at the evaporator, the compressor, the...." >

[vodkas]

Had to take one of my precious days holidays today to try and get it sorted.

 

MSF ford dont have an auxilary belt in and got to wait till 2.30 for one to be delivered. Day is almost over by then, any way only

[ridway]

Seatkid

 

I concur with Nimrod's comments. A purge using inert dry nitrogen depends on how long the system has been left over a period of time. Using a high quality vacuum pump with a fresh oil change will allow the system to be evacuated (<=3 millibar) to a level that will allow any water, moisture or water vapour that has got in the system to flash or boil to vapour and be sucked out by the vac pump.

 

Water is a killer if it gets in a system, the reasons are firstly it can freeze, ice = iceberg, compressor = Titanic. Ice particles will also block the orifice on the TEV this is the device that meters the refrigerant into the evaporator. Lastly water reacts with refrigerant and it's oil to form acids which erode the system internally.

 

The dillema with the need for purging with nitrogen is how much moisture has got in the system? A good vacuum pump will always turn any water to vapour and suck it out but never all of it because a true vacuum can never be acheived. A proportion of the residual air left in will contain a small amout of moisture. Purging with nitrogen allows the residual air and any moisture to replace the vacuum. This could be repeated several times if desired (a technique called triple-vacuuming) to acheive a theoretically totally dry system.

 

The saviour here is the system's filter dryer. A system that needs recharging after several years use, and has been reported as getting slowly less effective will probably just require a small top up with gas. A system in this condition would always have had a greater pressure than atmospheric so no air or moisture would ever get in the system. A system that has lost all of its gas in a relatively short period has a leak which needs rectifying. When rectified consideration should be given to replacing the filter dryer as moisture content ingress is unknown. If the system has been left open to atmosphere for any length of time (repair to a front end crunch for instance), then changing of the filter dryer plus a purge with dry nitrogen is certainly good practice.

 

A reasonable benchmark is that the filter dryer has the capacity to catch any residual moisture in the system after a good vacuum session on a leak free system that has not been open for a longer period than necessary to change a system component on a dry day in a garage.

 

So in the case of your leaking evaporator, tread carefully. At least after changing it, which is a marathon I assume behind that dash, change the filter/dryer unit. Then give it the best vacuum you can with a pump that has had a fresh oil change, for as long as you can.

 

As a footnote keep everything as clean as possible, don't shipwreck the compressor.

 

It is more than likely that many garages would not have the facillity to purge with nitrogen. A specialist installer of split fixed systems would be you best bet because they purge copper refrigerent pipes with nitrogen while brazing them to prevent oxidization.

 

Best of luck behind that dashboard

 

Rich

[Guest nimrod]

Best of luck behind that dashboard

 

Rich

just the dash! :lol: half the engine bay has to come out! the wiper mech has to be moved, the coolant bottle, the fuse box and all the engine shroud around the battery area has to come out in order to get to the rear of the heater box and the necessary pipe work, its not a five minute job :o my guy quoted 9 hrs! it was more like 4 days :lol: although the total cost was still for the 9 hrs labour!

[vodkas]

Now that the compressor is banjaxed i ran an AC specialist for advise and price.

 

New comp

[Ivor_E_Tower]

So, what are you going to do? Bite the bullet and fork out

[ALARM MAN]

http://www.4s-europe.com/main_catalogue.asp

 

 

these people supply OE compressors and parts if it helps

 

We had big problems but now sorted

There is no easy way with these im afraid

 

Good Luck

 

I wont say Chill out Not fair :lol:

[vodkas]

For the moment I will have to get warm. The clutch has been electrically isolated so I can't engage it by mistake and the climate control can still run in auto mode. Obviously there is no chilling or dehumidifying but you can set a temperature and use the outside air same as eco mode.

 

I AIN'T SPENDING

[Dally]

vodkas

 

You may not have had a/c before, but I doubt you ever had a greenhouse on wheels either!!