Blocked TX Valve

[abl567]

I've had some electrical problems with my A/C leading up to summer so took the easy route and dropped into a local Auto leccy who diagnosed and fixed a hot contact on the A/C relay and a corroded contact on the control fuse feeding it.
Vaced it down and charged the system with 780gm 134a and it was cooling, just
After evacuating the system and testing the drier again the only cause for the poor cooling was a blocked TX valve, located deep under the passangers side dash
Thankfully removal of the fan and 6 slide clips later revealed the evap coil and TX Valve in sort of easy reach. I hope the A/C fellow thinks so

Along with the new TX valve I will replace all the A/C hoses to and from the compressor to elimate leaks

More to come

 

[Styria]

Hi abl567, steady on now, boy.
If you have black hoses, they were all new at the time when the car was restored. If you still have the original RED hoses, try and retain them. They're made of gold, and should just about last out the car.

That's a nice little job, in that left hand upper corner - not something you would want to do every day. You know, another job that one may need to tackle one day is the heater box - it's got to be one of the worst jobs on a 108/109. It is important to use the heater and cooling slides regularly, because you do not want the water valves to seize in the copper housings. Getting to them means a heater-out job and it's not nice.

Anyway, good luck in this instance - let me know if I can help in any way. Regards Styria

 

[BAR]

I'm chasing down my AC problem. So far eliminated the Pressure switch on the receiver / dryer, but haven't ruled out the TX valve.

Any pictures as to its location under the dash?

Also where to source a replacement?

 

[BenzBoy]

I'm chasing down my AC problem. So far eliminated the Pressure switch on the receiver / dryer, but haven't ruled out the TX valve.

Any pictures as to its location under the dash?

Also where to source a replacement?

I don't have a picture. My understanding is that the TX valve can be a generic one so long as the specs are correct. I'm about to replace the TX valve on the Spirit and my R-R tech man told me any would do so long as it fitted and was the correct temp range. The same happened with my Alfa 164 and we used a generic one on that with good results.
Regards,
Benz-Boy

 

[abl567]

I don't have a picture. My understanding is that the TX valve can be a generic one so long as the specs are correct. I'm about to replace the TX valve on the Spirit and my R-R tech man told me any would do so long as it fitted and was the correct temp range. The same happened with my Alfa 164 and we used a generic one on that with good results.
Regards,
Benz-Boy

I'll try and post a pic today.
Correct that the TX valves are generic, so the parts price isnt a problem

 

[abl567]

The evap coil had to come out, took me an hour


Tomorrow the AC bloke replaces the TX valve, reciver/drier, all the hoses and connections as some bugger has put hose clamps on in the past and puts it all back together

 

[BenzBoy]

Ah. It will be nice and cool for Sunday. You're a good man Ant.
Regards,
Benz-Boy

 

[abl567]

All done and nice and cold.
We sealed up a heap of air leaks where the fan enters the evap plenum and the ducts to the vents, replaced the TX valve with an internally equalised one, replaced the thermostat inside the evap plenum, replaced every hose with new crimped fittings which eliminated 3 unused gauge ports and allowed for new O ring seals to be used, reducing the chance of leaks.
It now works very well with much improved air flow and a nice bite the air at the outlets and coped well in todays heat in northwest Sydney.
I'm pleased with the result and the cost was reasonable, just under 900 bucks including all parts. I had replaced the compressor 2 years earlier for 370bucks so I now have a almost new A/C system for less than 1400 bucks that should be cool for 15 years. Pun intended.
All I need to do to complete the job is reinstall the heater ducting, glove box and other bits and bobs I removed to drop the evap out.
Then clean up the mess and get ready for Sunday
Wash, clay bar, polish and wax twice should fill up Saturday nicely

 

[abl567]

Ah. It will be nice and cool for Sunday. You're a good man Ant.
Regards,
Benz-Boy

Thanks Brian.
I really enjoy working on my car, hand and forearm injuries are a small price to pay for improving my car and I find it a great release from dealing with the pressures of running a small business.
The part I most enjoy at work is fixing/improving the machinery and then watching it produce, it is very satisfying

 

[Styria]

Do you still feel the same way ? I am just wondering how you are progressing with the big 6.3 monster. It's an old thread alright, but interesting to look back upon after all this time. Regards Styria