92 coupe auto LT1

I got my Vette month and a half ago. It has the R134 fittings. There is no cold air coming out and the clutch does not engage. I checked it for freon...the gauges said it was empty (snapon gauges, hooked red to high, blue to low pressure. Checked for codes by pushing the 2 fan buttons for 5 seconds and then pressing the middle button...it displays 00 if i push it twice it says -00....no 09 code and no freon. This is my first time trying to recharge a vehicle. I searched the forum, thats how I got this far. I have a 1990 FSM...are the 90 and 92 ac systems similar enough? I dont know what to do next. Any help appreciated

Jason

 

This is your lucky day. Check out the tread from a few days ago titled "No power at AC clutch connector on a 91".
SunCr is the AC guru, but others contributed.

Good luck.

 

It doesn't run without gas and 0 on the gages is no gas. Go to an a/c shop and have them leak test it - it doesn't cost a fortune - and before you go, make sure you disconnect and reconnect the battery. It may have set a trouble code for the Pressure Sensor (which is a PCM code and that won't be displayed in the HVAC controls). And assuming your Vette has that diagnostic built into it, it may not start up without the Code being cleared. Some a/c shops don't know that, so there's no reason to complicate it for them. Once you know where the leak is, you can figure out how to repair it - or a shop will probably refund the leak test charge if you let them dig into it.

 

When you got the car a month ago, did the AC work then, or did you purchase the car with the AC not working?

If it was working for awhile after you purchased it, you can do a quick visual on the AC hoses. Look for visable oily greasy buildup or deposits on the hose. This usually indicates a leaky hose. These leaks often happen where the metal lines are crimpped to rubber hose. Also look around the compressor clutch and see if it has thrown oil around. If the clutch is leaking, you will usually see oil thrown on the underside of hood, right above where the compressor is located.

Going to an AC specialist is a good idea, just be careful, they can charge an arm and leg....In any case, if you have no pressure at the high or low valaves, this indicates that your AC system is completely discharged. Will require fixing and then "draw down" before re-charge. Does the compressor have a Tag on it indicating it is R-134 ? If it has the R-134 fittings, my assumption is that it was converted over from R-12 to R-134. Your system will require about 36 ounces of R-134 and 9 ounces of PAG-150 oil (keep in mind thath these amounts would be required in a completely flushed and dry system. Knowing how much oil to add is the tricky part and depends on what components are replaced, receiver dryer, compressor, etc. )

 

I'd put in a can of 134 first, and see if it stays in there for a couple of days. If not, THEN go to the shop for leak detection. If it holds, just put in another can of 134.

Buy a mickey mouse gauge kit. Absolute pressures might not be accurate (and then they might too), but you can tell differences in before and after measurements..

My

 

If you do not know anything about Hvac i would take it in to a shop. With the system at 0 pressure there is a chance of air and non-condensables to get into the system. It needs to be leak checked, the drier should be changed and evacuated and recharged. Its not worth doing it half azzed.

 

After the mechanic having it for 5 days I told him I would just come get it. He said he got 26 ounces of freon in it and when he grounds the green wire with the yellow stripe that goes to the sensor on the low pressure line everything works great. I read on here that your supposed to put in 36 ounces of freon. When I mentioned that to him he said "It says 28 ounces on the label in the engine bay" I said "okay", he said "I think its the ac clutch relay" I said "I can change that" so I pick it up and im driving home and I catch a blinking light out of the corner of my eye...its the hvac head unit telling me that it has a code 09 low freon. So now im thinking maybe he didnt put enough freon in after he leak tested and refilled. I think im going to add some freon tomorrow