Bubbles in AC sight-glass
 

My car is a '95 E300 Diesel with R134.

The current ambient temperature is around 40F. I turned on the AC and noted bubbles in the sight glass. The compressor cycled on-and-off normally.

Do the bubbles in the sight glass mean that i am a bit low on freon, or is that a normal condition when the ambient temperature is that low.

If so, can I expect these bubbles to disappear once the ambient temperature reaches 70F+


Phil

Is the engine idling?

I'd expect a few bubbles at such a cold temp... It's always easiest to check charge on a very hot day- 90-100F.


Michael

The bubbles are there both at idle, as well as at around 2000 RPM. I have not checked for bubbles at a higher RPM.

Phil

At such a low temp the sight glass means nothing. When you have an ambient of about 80 or greater then it is an indication worth paying attention to.

Evaluating an a/c's performance in cool weather is a waste of time.

Good luck,