OK .... I know just enough about A/C to be dangerous.

My wife says she has no A/C in the 2012 Dodge Caravan

I put a gauge on it ... sure enough, 20 lbs on the low side ... 100 on the high.

So, vacuum the system

Put in freon with leak stop (134a ... 40.5 oz) ....

Now I get 40 on the low but 200 on the high going up to 290 then back to 200 constantly every 20 or 30 seconds.

What did I do wrong?

Compressor is staying on (not cutting on or off).

The van does have dual air (front and back).

Any advice would be great!

Thanks .... Mike

 

Check your refrigerant level without turning AC on, both sides should be balance, you perform this check first thing in morning before turning your van on.

 

Thanks ...I will try that. I did read how the pressure should relate to temperature ... and I see the temperature indicators on my pressure gauges.

I actually went and vacuumed down the system again today ... and refilled it with straight 134a (no leak stop) ... 40.5 oz (or just an oz or two more ... hard to read a cheap scale with a can and hose on it).

It was warm today (mid 80's .... had 50 on the low side and 260 on the high.

The system was stable and seems to be working .... no fluctuation on the gauge like last night.

Not sure what I did wrong yesterday.

I still suspect I have a very small leak .... both input and output pressures dropped by half after two months.

Thanks again ... Mike

 

Check both shredder valves with soapy water.

 

Good thought .... I will do that.

Thanks!

 

Any product with leak stop is a bad idea and should never be used. It plugs up the Drier/Filter and contaminates a shop's a/c equipment. Some R134a replacement products such as Redtek also contaminant shop equipment and some are downright flammable. If I knew that those products had been used I would refuse to service the vehicle rather than risk expense damage to my equipment. A sure sign of low refrigerant level without using a gauge is listening for a hissing sound from the dash when the compressor cycles on and off. That said older vans with rear a/c are prone to failure where the rear a/c lines bolt up to the rear expansion valve right behind the passenger rear wheel. It's open to constant road splash. Running any a/c equipped vans low on refrigerant will result in compressor failure as the refrigerant moves the lubricating oil through the system. Everything runs off of 1 belt when the compressor seizes your done. Better to disconnect the electrical connector if it is not working right. Could be many other things leaking as well. If you can't spot the leak due to oil/dirt accumulation at a certain spot then I would recommend the addition of a fluorescent tracer dye to the system. Using a black light leaks stick out like a sore thumb. It's a process of elimination if no external leaks are seen then it is internal and points to front or rear evaporators. If the charge is correct and you still have high/low pressure issues look into the expansion valves and the rad fans. No matter what it's not cheap.

 

Since I evacuated the system and filled it again with straight 134a (no stop leak) ... it seems to be working (a few weeks now).

I am guessing there is a very very small leak ... seems to leak about 1/2 the pressure every few months.

Here in VT, just a few more weeks of "hot" .. if you can call 80's hot .. weather.

By next year I will have a new shop and can take a good look at things.

I did have a leak once rear lines .... replaced them ... worked for three years ...now a new leak.

Thanks!

Just FYI .... videos of me building the new shop .... https://www.youtube.com/channel/UCYA...lfPxOTVmYMoAjg

 

I read stop leak gasses are not good for the person who will service later. In addition Late caravans use 1234yf freon instead of 134a.