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AC problems again

16K views 48 replies 5 participants last post by  amaster88 
#1 ·
I have a 2001 Dodge Intrepid SE 2.7 V-6. I recently charged my AC and after a few problems, the AC blew cold for a few weeks up to today, Today I turned the AC on, it worked fine, when I got to to a stop light I turned it off, a few minutes later, turned it back on, nothing happened. Check the AC compressor, getting no pressure when car is on, but when it's off I get a static pressure reading, the clutch is engaging, I made sure of it, after checking all the fuses and relays, the clutch is engaging, but the compressor I'm not sure if its running. It did this to my last time, I couldn't get a running pressure measure, but I could get static pressure readings, what should be my next move be? I don't want to try charge it, it won't do any good until I know if the compressor is seized or not, could the drive belt be causing any problems?
 
#2 ·
When you look from the front of the car into the compressor clutch, the center part is actually rigidly attached to the compressor shaft. When the clutch is not engaged, the outer (pulley) part of the clutch will be spinning when the engine is running, but that center part (think: compressor shaft) will be at a standstill. When the clutch is engaged, if the center part is rotating *with* the pulley part, then the clutch is by definition running.

Recognizing that so you can determine if the compressor is being turned is the first step.
 
#5 ·
What are you using to get the pressure readings? A proper AC gauge set or relying on the cheap gauge of one of those DIY cans of refrigerant you buy at the auto parts store?
 
#6 ·
the cheap gauge, I get a high static pressure reading from low side, Without doing too much more, I'm going to Meineke tomorrow after school to get a diagnosis. Their website says they do it for free, so hopefully they can tell me for sure what is wrong, and how much it's going to cost.
 
#8 ·
...I'm going to Meineke tomorrow after school to get a diagnosis. Their website says they do it for free, so hopefully they can tell me for sure what is wrong, and how much it's going to cost.
Just be careful. I don't have any personal experience with Meineke, but a lot of these chain stores are experts at "upselling" if you know what I mean. Think thru everything they tell you it needs, and check back here on anything you don't understand so you don't get taken.

If you have a Harbor Freight store near you I'd recommend getting this gauge set:

http://www.harborfreight.com/automotive-motorcycle/refrigeration/a-c-manifold-gauge-set-92649.html

It's currently on sale for $39.99...
Ooh! That's a deal and a half.
 
#7 · (Edited)
#10 ·
Thank you guys so much. Yeah I'll be on my toes, Meineke screwed over my brother once when he had the brakes checked, they checked them, and told him that he couldn't leave until they fixed the brakes for it was a safety hazard ,700 bucks later....

I'll make sure they break everything down to me and check with you guys, and with other people that I know that know more about cars than I do. But yeah, their website said they diagnose for free.
 
#11 · (Edited)
I took it to them today, they didn't even look at it, they ask me a few questions, such as if I topped it off, I told them I did but the charge went out after two weeks. Without even further diagnosing it by inspection they flat out said it was a leak before even looking at or testing the system, what a bunch of bunk. So that means I have to plunk down 100's of dollars just to have it checked? A place said they did AC service for 29.95, which I'm sure is before the cost of refrigerant, but that's only if they are able to charge it, I'm not sure if they would actually do the dye test or any of the other tests that would indicate the actual problem of the non-existent AC, thats probably the fee for topping off without vacuuming the old stuff out and putting clean stuff in, I can top it off myself, and that's not a solution right now, whaddya guys think? should I take it to the shop thats gonna charge me 29.95 plus the cost of refrigerant?
 
#12 ·
also, when I do the psi check on the low side when the compressor is on, and it says 0psi, the gauge goes below 0 like its sucking, is that just the suction port or the compressor? is it possible UI could have got moisture or air enough in the system to cause blockage? thank you guys again.
 
#24 · (Edited)
At idle you should get a range of PSI on the Low side ranging 30-45 ish psi. 35psi being the key psi to achieve. On the high side I think I recall around 180-220 psi not sure entirely.

When you look at the gauge and your engine is above idle, the low side will be pulled into a suction.

I would suggest getting a correct set of gauges, and while the a/c is on and the gauges hooked up take a reading of the gauges, then if they are not reading in the above areas tap (with the handle of a screw driver or something plastic and slightly heavy) on the expansion block (should be a rectangular block of metal on the firewall two lines (big and small) hook too. See if that changes the pressure because I am thinking you do have a faulty expansion valve. Most compressors will not turn on if you do not have enough freon in the system.


And I know some of this, because I personally replaced every last a/c component in my car myself, and learned how to charge it.
 
#13 ·
If you don't know what you're doing...I suggest you take it to a professional or shop experienced with AC systems. Hate to see you get injured or damage the AC system by playing around with it.
 
#34 · (Edited)
You might have run it out of oil. If so, time for a new compressor. Recommend getting the Denso (the OEM one) new one from Advance. Costs a little more than the brand of the month whatever else they have, but the risk will be *so* much lower.

Lesson learned, eh?

Ron did say:
But you learn by doing.
:)
 
#14 ·
who should I take it to? Do you happen to know, roughly, what a pro would charge just to check? thank you. Like I said, I really am not trying to mess with it myself anymore, I want to take it to someone, but alot of those places are rip-offs, should I take it to the shop that charges 29.95 for ac service, or do you think they would actually help me? thank you
 
#15 ·
I don't have a clue. All I can suggest is you call around to different places and ask what they charge for the diagnostics service. As you already found out don't tell them you've been messing with it...just say it stopped working. If they don't put a proper gauge set on it..there's no way they can diagnose anything. You might look into some places like Firestone or Goodyear, etc. Meineke and some others have been known to lure you in cheap and then talk about several hundred dollars for repairs that may not really be needed.
 
#19 ·
DrDodge works at Firestone. He might be able to give you better insight as to what they do and charge. Maybe even a discount. Do a search for him and send him a PM and introduce yourself and see what he says.
 
#22 · (Edited)
I'm going into to have it checked Monday, but I was going to ask you guys another question, how long should the ac clutch run before cycling off than back on again, how long does it cycle, typically? basically how long should the compressor run before cycling off than back on? I was doing some research on this vast forum, lots of info, if you look long enough. if my compressor is running too long, could it be the A/C Evaporator that is causing the warm air? they say if the evaporator switch is messed up it freezes up the evaporator, and that could cause the air flow to be warm. Thank you

http://www.dodgeintrepid.net/archive/index.php/t-75102.html
 
#25 ·
Is the a.c. pressure switch (the thing that is responsible for cycling the compressor) maybe bad and keeping the compressor on all the time? Not unheard of for them to go bad.
 
#27 ·
okay thank you guys again. What would cause the compressor to stay on and cycle? Do you know how much the expansion valve would cost to replace? Is it by itself, or is it part of the receiver dryer unit, I've been doing plenty of research on these systems, I heard that the valve is sometimes part of the receiver/dryer unit, would you have to tear into the dash to get the valve out? Also, my dad, who unfortunately lives a 1000 miles away, knows about cars and ac systems, he says it sounds like the expansion valve to him, becuase the static pressure reading takes too long to get a standing reading, when I check the static pressure it keeps climbing for a minute or two, if the car's been off for a awhile, the static pressure reading is instant, but freshly shut off, it takes awhile, he says that could be the expansion valve going out.
 
#30 ·
just now: I checked the low pressure again, the static pressure took a while to build, I turned the car back on after I tapped the expansion valve with a screw driver, and played with the low side valve a bit, I turned the ac on and it was reading 35 psi on low side, it would go lower after I heard the ac cycle off and than go back to 35 after cycling back on, I checked the air from the vents, it was blowing cold air, cooler than vent without the ac on, and I checked the vent temp after the car was off and the ac was off, I went back turned the car on with vent only, luke warm air, then turned the ac on, the air got colder. I think its either the expansion valve getting stuck or something like it.
 
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