02 Saturn Vue blowing hot air

[beertracker]

It's a 02 Saturn Vue and it just started blowing hot air from AC vent. No previous AC work has been performed. I checked the compressor and it is engaged. I connected a pressure gauge to the low pressure side and it reads 100 psi (in the red) with engine and compressor running. What causes this high reading? I believe I am on the low pressure side since the gauge instructions said the connector only fits the low pressure side.

The engine temp is slightly below middle range. Engine radiator fan is running.
Thanks,
BT

[ACProf]

I believe what you are seeing is the compressor PULLEY turning and NOT the end hub which is actually connected to the shaft of the compressor. So, YES, the PULLEY is turning, but the magnetic clutch that engages the hub to the pulley is not activated and the hub is NOT turning.

100 psi is NORMAL pressure in the low sideline when the compressor is not running. Its called static pressure. THe colors on the gauge (and instructions on the bottle) say that the COMPRESSOR (not just the pulley) must be turning when you read the pressure.

If you look in the chart in the first post on this forum and find 100psi for R-134a and then go directly over to temperature you will find the temperature is about 90 degrees. THat's the temperature of the refrigerant at the time you took the reading.

So, the REAL problem is why isn't the magnetic clutch engaging. Sounds like something electric, like a fuse, a bad connection, a bad or broken sensor, or a bad compressor clutch coil.

IF the end hub really is turning, then the compressor is shot.

ACProf

[beertracker]

I checked the compressor again and the compressor hub is definately turning. I checked fuses and coil wiring and didn't see any thing wrong. Plus I can hear the electric clutch click into place when I turn on the AC. I suppose the only way to make sure the compressor is turning is to take the compressor off and dismantle the electric clutch and coil? I suppose the electric clutch to compressor shaft could be broken? The car has 128,000 miles, V6, auto. As you stated earlier if the compressor doesn't turn the AC low side static pressure will be high. That is what I am seeing.

I guess I will take the compressor off and see where this leads me? Let me know if you have any more suggestions. Thank you.

BT

[ACProf]

I've never seen a compressor shaft break or come apart. There is a metal keyway joining the two together. The 'click' you mention says everything is working on the front end. I doubt that that's the problem. Special tools are necessary to remove the clutch hub, pulley, and coil. You WILL ruin the compressor if you try using standard mechanics tool.

Before you start dismantling things and throwing parts at a problem and fall into a DIY money pit, a few more diagnostics are necessary.

Buy or borrow a REAL set of AC manifold gauges. This is a primary diagnostic tool. You can borrow a set for free from most autoparts chain stores for just a returnable deposit when returned.

The pressures with the compressor turning, AC on HIGH fan, windows open, engine running about 1200-1500 RPM will tell the story.

The system could be just very low on refrigerant. THe high side pressure will tell the story.

If it IS LOW, (most common problem) there is a slow leak in the system. Could be the front seal of the compressor. Look for oily residue sprayed on the hood above the compressor. Get a good look at the compressor shell and the bottom of the clutch area - is it covered by an oil slick?

Check all the other fittings and hose connections. The crimped hose connections DO wear out and leak. They will be covered with oil too.

Next thing to do would be to have the system refrigerant that is still in the system recovered, and then a full vacuum pulled on the system to see if it holds. If it does, then a total refrigerant recharge into the vacuum (by weight). Now the system can have a full diagnostic to see if everything is working correctly.

If the vacuum doesn't hold, then the source of the leak must be found and repaired first, or the recharge will just leak out and be wasted.

Do you plan on doing this work yourself?
ACProf

[beertracker]

I will rent or borrow some real manifold gauges from Auto Zone on Monday and get back with you. I will have to ask if they have vacuum pumps also. Let's see what the manifold gauges indicate then I will decide if I can do the work my self?

Thanks,
BT

[Tom Greenleaf]

I don't go there but believe most do rent vacuum pumps - ask,

T

[cross6]

Autozone definitely rents Vac pumps, where I always go. You can get a Mastercool pump unit for a $200 deposit.

[beertracker]

Well I struck out 3 for 3. O'Reilly and Advance Auto Parts do not rent out AC gauges. Auto Zone does but their gauges are currently out on loan. Not wanting to put up with TX heat any longer I took the Vue in and it has a small leak and the compressor is weak. Looks like I will be doing some AC work.

Thanks,
BT

[thomasrandy]

Old thread now. Start a new one for what is current. Please don't post YOUR problems on another's thread. Your sign off if not eliminated is not in my favor so please get rid of it,

T

(edited by me and change post now please)

[Tom Greenleaf]

Gauges etc: If you can't afford to just buy the stuff then just send it out. This trade is NOT for everyone and most shouldn't touch it. Stuff sold right here isn't that bad $$ wise. Try screwing it all up and see the price,

Tom

[buickwagon]

Stuff sold right here isn't that bad $$ wise.

Speaking of stuff sold here, the "Shop Tools" link has been "Under Construction" and the "Shop Parts" link tells me "Your website is ready" for quite some time now -- ever since the crash. Makes it kind of hard to support the site sponsor. Anyone know if they will be rebuilt any time in the near future?

[Tom Greenleaf]

A or B - wait for site fix or buy where you want. I have no vested interest in this site but amazed by the techs here,

Tom