Aircon Sealer Recommendation

[Matt Schubert]

Hi everyone. Not sure if this is the correct section but I’ll give it a go. I have a 2014 E350 that Mercedes regassed for me and told me there is no leak on the system. After just two months it wasn’t blowing cold again and I tried a second garage who told me there were no leaks detected, but there was only 50gms of refrigerant left. So it’s lost approx 500gms of refrigerant in just two months but no leaks are being detected. Whenever the AC stops blowing cold, theres a constant sucking noise from behind the dash which I think is due the residual R134a rushing around the free space in the evaporator. My question is does anyone here have experience of using the STP aircon sealer and what degree of success did you have?

 

[matthew k]

I had a similar issue with a Peugeot 406 years ago. It was pressure tested and worked fine after a regas but within a month had lost the gas. The same thing happened after it was regassed for a second time. It seemed likely it was loosing gas through the compressor seals while it was running. The gurgling is likely due to low refrigerant.

 

[Wighty]

Hi everyone. Not sure if this is the correct section but I’ll give it a go. I have a 2014 E350 that Mercedes regassed for me and told me there is no leak on the system. After just two months it wasn’t blowing cold again and I tried a second garage who told me there were no leaks detected, but there was only 50gms of refrigerant left. So it’s lost approx 500gms of refrigerant in just two months but no leaks are being detected. Whenever the AC stops blowing cold, theres a constant sucking noise from behind the dash which I think is due the residual R134a rushing around the free space in the evaporator. My question is does anyone here have experience of using the STP aircon sealer and what degree of success did you have?

The aircon specialists , rather than garages who just have a plug in machines should be your go to now . They can inject a uv dye that shows leaks . Also the modern leak sealers they use may be better than a diy version .
Sometimes the valves that leak are the ones the hoses connect to and maybe don’t show up as an issue until the hoses are disconnected ?

 

[Steve@Avantgarde]

The usual suspect is the condenser, mainly because it takes a battering from the debris flying through the front grille. If the previous garage injected a UV dye (almost all AC machines these days won't regas without that phase being completed) then it should be an easy spot. Also look for any damp on the condenser or pipework where the PAG oil is also escaping from.

Your AC on your car is no different to your fridge at home, and that I assume doesn't eat AC gas....in other words its a sealed system that should remain leak tight.

 

[mioba]

Any AC specialist will put dye in the system and send you away to come back a few days later. A check of the system with the UV will soon ID the leak, do post back and let us know how you got on.

I would also be inclined to write to your dealer and tell them you paid for nothing....see what their goodwill is!

As for pour n sealers, dont bother. They dont fix and may well block something else.

 

[Matt Schubert]

Thanks all for your input. I’ll post back when I know more.

 

[Matt Schubert]

Any AC specialist will put dye in the system and send you away to come back a few days later. A check of the system with the UV will soon ID the leak, do post back and let us know how you got on.

I would also be inclined to write to your dealer and tell them you paid for nothing....see what their goodwill is!

As for pour n sealers, dont bother. They dont fix and may well block something else.

The main dealer in MK can’t troubleshoot this issue because their AC diagnostics is faulty. I’ve also fallen out of love with them over a £540 oil change on this E350. Ridiculous.

 

[Wighty]

The main dealer in MK can’t troubleshoot this issue because their AC diagnostics is faulty. I’ve also fallen out of love with them over a £540 oil change on this E350. Ridiculous.

What about an AC specialist (not MB ) ?

 

[Matt Schubert]

What about an AC specialist (not MB ) ?

I’ll give the local garage one more shot at finding the fault. They are generally a very good independent garage and I’ve found them to be very trustworthy since using them. Failing that I’ll find a specialist.

 

[Wighty]

I’ll give the local garage one more shot at finding the fault. They are generally a very good independent garage and I’ve found them to be very trustworthy since using them. Failing that I’ll find a specialist.

As long as they inject uv dye you have a chance

 

[Wighty]

Your user pic is making me hungry

 

[mioba]

without digressing, how the hell did you pay over 500 notes for oil change.

 

[Matt Schubert]

without digressing, how the hell did you pay over 500 notes for oil change.

“it’s fixed price servicing sir, you should have been given the price before we started”. No **** Sherlock! Last time I use a main dealer.

 

[joderest]

what!!! over £500 for simple service !!!!, oil filter at best is £20, oil maybe £80 (if using good stuff) 1 hours labour maybe £150.
What a rip off.

Air con, the bloke that does mine said there are some good advances in leak sealing stuff for air con, but also said he would be very careful, as it may well seal a leak, but bugger something else up, like the compressor. His moto is, it should work like it was designed, find the faulty bit and replace it.
Small leaks are almost always the condenser or dryer, and very difficult to find.

 

[RhodieBill]

I've used this,
Mastercool 53615 Air Conditioning HVAC Master Leak Shield Stop Sealer twice, worked both times.

It's imported from the US so is not cheap. I think the last I paid was about £26 on Ebay. But only works on slow leaks - ie 3-4 weeks to leak.

The bottle looks like this.

 

[LostKiwi]

I've used this,
Mastercool 53615 Air Conditioning HVAC Master Leak Shield Stop Sealer twice, worked both times.

It's imported from the US so is not cheap. I think the last I paid was about £26 on Ebay. But only works on slow leaks - ie 3-4 weeks to leak.

The bottle looks like this.

Unlikely to fix compressor seals though.

 

[RhodieBill]

Both times mine was leaking by the thing with a little glass window on it. Well on the Beemer it has a window, not on the Merc. Forgotten what it's called.
Anyway, it worked that's all I cared about!

 

[mioba]

Things should be fixed to the way they left the factory and were intended. anything else is just a bodge job.

 

[RhodieBill]

Things should be fixed to the way they left the factory and were intended. anything else is just a bodge job.

Well, some of us don't like throwing away ****ing money unnecessarily on a 20 year old car - dick!

 

[alexanderfoti]

Both times mine was leaking by the thing with a little glass window on it. Well on the Beemer it has a window, not on the Merc. Forgotten what it's called.
Anyway, it worked that's all I cared about!

Sight glass, MB's havent had them for yeaaaaaaaaaaaars

Most of the sealers will just gunk up the system and get stuck in the receiver dryer. If its a £500 car that you don't car too much then give it a go, I would be inclined to find the leak and sort it.