1993 300 SE a/c intermittent problem

Hi,a friend of mine has intermittent problem with air-con (sometime it works fine, sometime don't), blowing cold air n at times not. Appreciate if someone can help.
Joey
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Check the sight glass on the receiver/dryer and see, when it's blowing cold air, how many bubbles you observe in the freon flow. If there're lots of bubbles, add freon and it should work okay.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Funny thing, I JUST had the same problem on my '82 300SD. It would blow cold for awhile then suddenly blow hot. The climate control works fine, because the blower kicks into high to try to cool the car, but nothing but hot air came out. Shut it off for about 15 minutes and it'll blow cold again. So I took it in to have the freon charged. Turned out it was the same price to have the system converted instead of paying for the freon and found that the problem wasn't solved. The final diagnosis: the compressor couldn't keep up with the system (remember it's 22 years old) when it got too hot. Solution: I'll need to replace the compressor and associated parts. And I HAVE to do it here in 122 degree Phoenix. (But it's a DRY heat)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That's odd behavior for an "old" compressor. The cold to warmer transition should have been gradual, not abrupt. I bet the clutch was bad and when you bought the new compressor, it came with a new clutch.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

therefore at times, the magnetic clutch is not engaging the compressor. Try by-passing the pressure switch and if the compressor works, then it's time to replace the pressure switch.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Drive belt if loose will cause the speed sensor to turn off the clutch power and Wal-mart and all Dept stores and Auto parts have a very easy to use rechage kits with a Gage to tell you the proper charge pressure.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.