Need ac help!

[Bear]

First of all, I did do an ac search but didn't see anything specific to my problem.
99 Dodge Dakota - ac works most of the time. It may stop during a drive or may not start up again after a short stop. This can happen at any ambient temperature and I can't seem to pick up on a ny pattern. I checked the pressure with one of those gauges you get w/refills tanks and it reads good. Temperature out of the dashboard vent registers from 38F to 40F on a digital thermometer when it's running well. Any suggestions?

 

[Quest]

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=24;t=003803

 

[toocrazy2yoo]

quote:

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I checked the pressure with one of those gauges you get w/refills tanks and it reads good. Temperature out of the dashboard vent registers from 38F to 40F on a digital thermometer when it's running well. Any suggestions?

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Bear, when you say "reads good", what's the figure? Those gauges read the suction, or low-pressure side, which, at around 80-90 degrees F should be somewhere around 30-60 PSIG.

You have a pretty good duct temp, my guess is you have an intermittantly bad low-pressure switch which cuts power to the compressor solenoid. If the charge is good, and the components are good, look to faulty parts that interrupt the process. Vacuum lines leaking, or misrouted in a recent repair can swing temp control partitions to the warm side also.

Another weird thing that happens, especially with older systems, is bits of receiver/drier element can float around inside the drier, intermittantly blocking the outlet carrying the freon out to the compressor. Other troubles could be the wiring, or the AC button on the dash. Bad wiring and control knobs are less likely causes, however.

GL!

 

[Bear]

Thanks guys, I will check the low -p switch and wiring and get a actual psig reading.
Quest, I did read that thread but it seemed like that problem was constant, whereas mine is intermitant.

 

[toocrazy2yoo]

Hey Bear? My bad

quote:

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Another weird thing that happens, especially with older systems, is bits of receiver/drier element can float around inside the drier, intermittantly blocking the outlet carrying the freon out to the compressor

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Should have read FROM the compressor. The drier is on the high side after the compressor but ahead of the expansion valve in the unit under the dashboard. Thought I'd mention, sorry about that.

 

[Bear]

Once again thanks for the replies, but it turns out it was the bearing(s) that ****ped out. Apparently the clutch would sometimes just disengage. The pulley had a good 1/2" play in it when the belt was removed. My mechanic checked it and said that the whole compressor would have to be replaced - no clutch/shaft only replacement was available. $250 for the compressor alone. So for now I installed the shorter belt that just bypasses it. This gives me till spring time to come up with the cash to replace the unit.