Ugh. AC is not working at all now. It’s been cold, almost too cold. But today, nothing but ambient air. It’s not cooling at all. It’s just like outside air. No dashboard lights.

I guess I need to take it in. Any thing I should check before doing so?

I Have had both my van's (GM late 90's) AC compressors replaced. One last summer. The other this summer. Both work great now. Was $500 parts and labor for each one. Btw, not sure how common it is. Both systems were checked and charged. When, like yours that did not fix the problem and it was determined the compressor needed replaced. They did not charge me for the recharge once the new compressor was installed. Not cheap, but if you plan to keep the vehicle and drive during the summer it is pretty nice.

quote:

It’s been cold, almost too cold. But today, nothing but ambient air.

Sounds like it is time for a compressor replacement.

I did the Mercedes a while back and it was <$600 for the compressor. When I complained, my guy told be I was lucky it wasn't a Scion...they are $1600

Check that the compressor comes on. It may require running AC with the windows open, AC on full, temp turned all the way down. Make sure the compressor turns on, and off. Once the compressor is engaged, you'll find two large lines; feel them (carefully; one should get hot, the other should get cold. If there's no difference, you may be undercharged. Don't simply go get a "kit" and attempt to charge it.

R134 usually comes with oil for the compressor; if one keeps charging the system, one keeps adding oil, and even if there's a leak, you'll lose gas, but a lot of fluid remains; too much and you'll have problems and can blow hoses or the compressor.

A common problem and a very cheap fix is the expansion valve; a small plastic screen that goes in the line between the high and low pressure hoses (hot hose is high pressure, cold hose is low pressure).

If the system is opened, it needs to be drawn down using a vacuum to remove all moisture, prior to inserting coolant. The coolant shouldn't be run through a cheap "kit" from walmart or the auto store. You should use an air conditioning manifold that attaches to the high and low side for troubleshooting, and from which you can shut off the high side and charge the low side while the engine is running.

Whatever you do, don't attempt to recharge into the high side while it's pressurized; you can burst the can in your hand.

Use a charge can that has dye, or get some air conditioning dye and pour it in the charge line before you attach the can. You can inspect the a/c system with an ultraviolet light to look for leakage points.

The charge valves are common leak points, and use valve cores that look the same as you'll find in inner tubes. Replacement valves are inexpensive.

Thanks guys.

Dumb question: how can I tell if the compressor is on or off?

It’s been fine for the past couple of months since the recharge. Today, nothing. Not gradual but abrupt loss of cooling. Is this symptomatic of a leak or a failure?

quote:

Originally posted by konata88:
Thanks guys.

Dumb question: how can I tell if the compressor is on or off?

It’s been fine for the past couple of months since the recharge. Today, nothing. Not gradual but abrupt loss of cooling. Is this symptomatic of a leak or a failure?

When you turn on the air conditioning, do you hear a change in the engine? Do you feel a bump or something "kick in?" That's the compressor.

The compressor in most cars is turned by a belt. That belt is turning all the time. It uses an electric clutch to engage the compressor when the temperature sensor in the system tells the A/C to get cooler, and disengages the compressor when needed. If you know what the compressor looks like, you can have someone turn on the A/C while you're looking under the hood, and you'll see the compressor clutch engage and the compressor begin turning.

If the compressor is not turning on and off, it may be the temp sensor, or the wiring, or one of several other components. You may have a fuse and/or relay that's failed. If you know where in your system to find the plug that attaches to the sensor, that can be disconnected and jumpered or bridged to run the compressor continuously (often done when charging the system). It's also a means of testing the compressor for function.

First step is to find out if the system is charged, and check system function. Make sure the compressor runs. If it doesn't, then it needs to be replaced, or a determination made if the components in the circuit for the compressor have continuity and function.

If you don't have the equipment to service your A/C (and by law, that includes the means to capture anything removed from the A/C system if it's opened), including a vacuum pump, service manifold, etc, then you're better off taking it to an A/C service center to have it evacuated and serviced, and troubleshot.

The above is exactly correct.

Personally, since you've had one loss of refrigerant already, I suspect you've had another one. A small leak might be tolerable if it still gets you through to the next season, but to lose all of it in less than two months is not a small leak. But don't go "giving it a 'shot' of 'Freon'" without determining if it actually needs it first.

Awesome. Thanks! I’ll try to figure out if it’s a compressor or sensor issue. After that, I guess it’s a trip to the shop. I need to squeeze a few more years out of her before I can afford a new car.

quote:

Originally posted by konata88:
Shop evacuated and found insufficient coolant. Didn't find any leaks but did find some damage to the condenser (likely rock damage through front grill).

It’s a closed system, there had to be a leak or it would not have been low on refrigerant. They would have seen the loss of vacuum after evacuating the system if they waited long enough.

I've always had one of the flexible hoses crack at the attach point.

Slow leaks have been the low pressure flex hose and rapid the high side.

Now when my truck lost the compressor, it was the clutch that gave up and disintegrated.

Bit of a thread drift -

If the a/c is cooling while driving but blows ambient if idling at a light, drive-through, etc., is this normal or is there a fix? Vehicle is a Dodge 2500 with Cummins. Had the compressor replaced last year, evaporator this year, fresh fluid & hoses too.

quote:

Originally posted by marksman41:
Bit of a thread drift -

If the a/c is cooling while driving but blows ambient if idling at a light, drive-through, etc., is this normal or is there a fix? Vehicle is a Dodge 2500 with Cummins. Had the compressor replaced last year, evaporator this year, fresh fluid & hoses too.

Expansion valve.

My only experience with a similar issue was a leaking evaporator in my 93 Accord. Huge pain to replace, but was able to DIY.

Those recharge kits and cans are pretty much worthless for R134a automotive systems. The only way to properly recharge is by weight. Find the leaks, evacuate the system, fix the leaks, vacuum the system down properly, check for vacuum loss, then weigh the proper charge in.

quote:

Originally posted by marksman41:
Bit of a thread drift -

If the a/c is cooling while driving but blows ambient if idling at a light, drive-through, etc., is this normal or is there a fix? Vehicle is a Dodge 2500 with Cummins. Had the compressor replaced last year, evaporator this year, fresh fluid & hoses too.

No that’s not normal. Check the radiator fan. That’s where the AC condenser is. If belt driven, the fan clutch maybe bad. If electric fans, and they’re not coming on, the AC won’t cool. You have to have air moving through the AC condenser. Driving down the road you get pretty good air flow. At a stop, if the fan/fans aren’t on and moving air, it will not cool. This should not be a huge repair bill.

Good luck to you.

What he said ^^^

quote:

Originally posted by konata88:
Ok. Will try recharge first. If more troubleshooting needed, will have them look at the door first.

Thanks guys!

Don't add refrigerant if it could be a blend door problem. Your system will be overcharged if that's the case.

This post is not just for the original poster, but also for the other poster who has a problem with no cold air while stopped.

No offense, but I learned a loooonng time ago:

You can't fix a problem until you've defined it.

The problem needs to be diagnosed and defined as to what it is.

Get the car diagnosed by a professional. The professional will know what is wrong, what it needs to be fixed, what parts, labor, procedures, etc.

Once that is determined, then it can be fixed. Fix that issue.

Throwing parts and labor at a problem is futile, expensive, and can be detrimental, causing more damage that can be even more expensive to fix.

Adding refrigerant, if not needed, is a mistake.

If you have a very minor refrigerant leak, then adding some refrigerant may be preferable to getting the actual leak fixed. That's a cost/benefit decision.

Good luck to you.

I tried to listen for the AC compressor when turning the AC on/off. Usually, when the AC turns on, the motor will sound different - like it's suddenly doing more work and idle speed will drop momentarily.

But now, nothing seems to happen. I guess the compressor is not kicking in.

Have an appt at the shop - it's 20 years old. I can't imagine the car is worth much so hope the repair isn't expensive. But I need the AC to be functional - not just for comfort but to keep the windows clear during the winter - safety.

quote:

Have an appt at the shop - it's 20 years old. I can't imagine the car is worth much so hope the repair isn't expensive. But I need the AC to be functional - not just for comfort but to keep the windows clear during the winter - safety.

^^^
Sometimes replacing the vehicle is best in the long run, particularly with 20 year old car.