Instant O/O and Load boards

Everyone you've talked to are right... if it's blowing cold air, it can't be clogged.

Usually when a system clogs up, it will be caused by a failed compressor—sending metal shavings into the screen at the expansion valve or orifice tube. The condenser and drier will sometimes plug up with crap after a failure too... but the evaporator? Ah... no.

Back in the day, we used to use a solvent to flush out the condenser... then the tree huggers outlawed the solvent—requiring the condenser to be replaced if it's plugged real bad. If it's just a few shavings, you can have an inline filter installed in the liquid line coming from the condenser.

I'd say they outright lied to you. Systems do not unclog themselves and start working again.

 

The cans I bought looked like fix-a-flat, just had a cheap plastic hose attached to the can of freon.





Maybe it was fix-a-flat. Just kidding

 

You can fill the system without gauges pretty accurately by one of two methods:

1. Place your hand on the evaporator outlet pipe. On a system that is low, the outlet pipe will be considerably warmer then the inlet pipe directly after the expansion valve.

Fill with freon until the inlet and outlet are approximately the same temp by feel. You will actually feel the pipe get cold when the evaporator is properly flooded.

2. Use the sight glass on the drier. When the compressor is running and liquid is flowing on the high side, there shouldn't be any bubble going by in the sight glass. Fill until the bubbles disappear.

 

could be they are AC stupid.
hey barcode, isn't there an oriface/expansion valve on the evaporator like a home A/C? i did HOME HAVC for 15 yrs. i am pretty ignorant on vehicle AC though.

 

I think they know your clueless and were looking for a quick buck. jumped right to the most expensive piece to replace too. probably was a rush peterbilt dealer too.. lol

 

When I worked in the GM dealerships, I could count on one hand the number of mechanics I worked with, who did A/C work, and actually knew what they were doing. Most of them knew nothing more than how to replace the whole #### system and charge it back up. Which does work... but is also extremely expensive, lol.

99% of problems with A/C are usually simple fixes... leaks... bad pressure switches... bad expansion valve... too much oil (never add oil to a system unless you have replaced a component)... or overcharging.

Leaky systems are probably the number one cause of A/C failure though.

 

I can't see anything in my sight lens. guess it's too old and crudded up.

I had to put a can in today and didn't have a gauge. I think I need another but I'm not sure. it's colder then it was but not much. it's real cold now but the sun went down and isn't as hot out. My system is buchered though. the compressor is hotwired bypassing the pressure switch. I havn't been too concerned about it since I have a direct drive fan with no clutch so it runs all the time. But I need to straighten it all out as i'm getting ready to put a fan clutch on it