A/C Schrader valve

[Bailes1992]

I need to replace one of the Schrader valves on my Wifes Dacia Logan MCV A/C system as it's passing a lot of gas (you can hear it) and I don't think the rubber seal on the cap is able to hold all the pressure. It needs topping up every 6 - 8 weeks.

I've done a lot of googling but I'm unable to find any information on them? Are there diffeerent types? Thread sizes? Seals? For different gas? Etc. Can anyone throw some information at me please!

 

[Astro14]

If you replace the valve, the entire system will need to be recharged. That requires someone licensed to do the AC work in the UK, does it not? So, I think the answer to your question would be to have the same engineer (we call them mechanics) that is going to recharge the system do the valve replacement.

 

[Trav]

You can change the valve with a tool like this. Amazon UK will have this or similar.

https://www.amazon.com/MASTERCOOL-81490-R134a-Remover-Installer/dp/B000KITSMI

Valves and caps.

https://www.amazon.com/Four-Seasons...beedc&pd_rd_wg=Pk2Fn&pd_rd_i=B0023TQEFQ&psc=1

 

[Bailes1992]

If you replace the valve, the entire system will need to be recharged. That requires someone licensed to do the AC work in the UK, does it not? So, I think the answer to your question would be to have the same engineer (we call them mechanics) that is going to recharge the system do the valve replacement.

Yes and no. I've been using alternative hydrocarbon based gas that you don't need a license for. If I wanted to use R1234YF, then yes I would need a license. I've already replaced the condensor as it was in an awful condition and gassed up the system, but it was only after I gassed it up did I hear the valve hissing away. I was hoping the screw on cap would keep the gas in but evidently not.

You can change the valve with a tool like this. Amazon UK will have this or similar.

https://www.amazon.com/MASTERCOOL-81490-R134a-Remover-Installer/dp/B000KITSMI

Valves and caps.

https://www.amazon.com/Four-Seasons...beedc&pd_rd_wg=Pk2Fn&pd_rd_i=B0023TQEFQ&psc=1

Thank you Trav! I've ordered a kit of assorted valves and a tool. I don't know why I didn't think of amazon.

 

[Kurtatron]

I did the same thing to my Toyota Previa/Estima this summer. I replaced the compressor, started recharging, then heard the hissing valve. The system had to be completely evacuated, but replacing the valves was as easy as unscrewing and screwing a new one in. Hasn’t needed a recharge for months now.

 

[mk378]

There are two basic types of valve, one is almost exactly like in a tire valve (except the rubber compound is different) and the other one is of the same design but larger diameter.

If the pressure goes to zero during the replacement or if the pressure has ever gone to zero, better performance is likely using a vacuum pump to remove the air. Don't release HC gas indoors it is a serious fire hazard-- not that it can't also burn or explode outdoors.

 

[brages]

There are two basic types of valve, one is almost exactly like in a tire valve (except the rubber compound is different) and the other one is of the same design but larger diameter.

If the pressure goes to zero during the replacement or if the pressure has ever gone to zero, better performance is likely using a vacuum pump to remove the air. Don't release HC gas indoors it is a serious fire hazard-- not that it can't also burn or explode outdoors.

There is also this kind - it looks as though it has something like a rubber ball inside. I don't believe they are serviceable - the whole valve must be replaced:

https://www.amazon.com/Buy-Auto-Supply-Aftermarket-Replacement/dp/B07D32XYSQ