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Comments
Good Morning! Thanks for getting back to me. Yes when i shut everything down, Heat/Ac and drive the truck it runs normally, no sound no nothing. I am going to try and charge the system as you suggested. I will let you know how it turns out. Thanks for the detailed instructions it was very helpful. I hope this works. I would really have to go through changing the compressor and having to spend $800.00.
Best Regards,
Natale
please post back wether it helps or not. This way it helps others in this forum too.
Thanks,
Arrie
I looked up the service bulletins on this truck and 01139B is the exact issue. Doing some more research, I found that it's a down problem where slugs of liquid refrigerant are being pushed into the compressor. They clog a tube which then blows the tensioner. Ugh.
I'm pissed because the AC kicks just fine. It's cold and the fan works. It's just noisy as all getout and sounds like the belt is going to go flying. This wasn't happening prior to them replacing the belt or the tensioner. I'm wondering if they could have reinstalled something wrong and caused the problem.
The shop quoted me $1300 to replace the compressor, tube, tensioner, etc. I just don't want to put that money into this truck right now. I'm having a hard time believing that this is the issue, if it was, it would have done this before the new belt. Right?
If the issue is that ...slugs of liquid refrigerant are being pushed into the compressor... then the fix for that is very simple...let some refrigerant out from the system. This is very easy to do. Just have a refrigerant charge hose connected to the low pressure side service port and let some refrigerant out. Have hose spraying in a container or something covering it with paper towels or something else so the refrigerant does not get on painted surfaces. It could hurt the paint.
If you let out big amount of refrigerant you might want to add an oil charge after that to make sure you don't drain the system from lubricating oil that the compressor needs.
If your compressor runs well and works, i.e. cools the air then if the compressor itself is quiet there is no need to replace it. And if it makes noise oil charge can fix that too.
The tensioner breaking right after new one is installed does not make sense. The tensioner simply is a pulley mounted in the end of an arm that is spring loaded against the belt. The way tensioner normally fails is that the bearing of the tensioner pulley wears out. Very seldom the spring breaks but is possible.
Almost sounds like the shop that fixed your tensioner installed the old broken tensioner back in and then tell you you need to replace $1300 worth of parts to fix it. I say this because I see so much scam amongst the car repair shops and it is getting much worse in a hurry. And it seems dealer service shops are amongst the worst ones with this.
I don't know if you are a hands-on person but a belt tensioner is not very difficult to fix/replace. In these vehicles I think you need to get under the car to do it though so you need to have vehicle elevated on ramps or at shop.
Here are steps I would take before costly compressor replacement:
1. Go to car parts store and buy A/C charging hose, pressure gauge, 2 cans of oil charge and 1 can of refrigerant. All this for about $30-$35.
2. Start car and turn A/C ON at max cooling.
3. Let run for a few minutes and then connect pressure gauge to the low pressure side service port. Record pressure reading. The pressure is ambient temperature dependent but the pressure gauge should have an area marked with green where the pressure reading should be at.
4. Use one of the oil charges, i.e. charge the A/C system with oil.
5. See if the oil charge helps any. One of the ways the noise from tensioner occurs is that the compressor could be hard to turn, i.e. low oil lubrication could cause the compressor run a little bit tight and at each piston compression stroke could cause drive belt tension change and start bouncing the tensioner that then causes the noise.
6. If problem does not get better let some refrigerant out. This would be necessary if slugs of liquid refrigerant enters in the compressor. No liquid should enter the compressor as liquids do not compress. Let out fairly big amount of refrigerant checking pressure at times and see if it helps. If the belt tensioner is broken you might need to have it fixed before you can definitely tell if your noise problem has improved but even with broken tensioner you should hear a difference.
After letting all that refrigerant out add the other oil charge in the system to make sure you have enough oil charge in it. If you happen to drain the system low enough so that the cooling performance goes bad then use the can of refrigerant to re-charge the system to point where cooling is good again.
If oil charge and lowering refrigerant level in the cooling system do not help you might be facing that $1300 repair cost. But, for making sure you are not spending all that money just because your compressor is running on low lubrication or the system is over charged (liquid entering compressor) the above explained less than $40 trouble shooting procedure might pay off.
There is another lower than $1300 cost repair to try before replacing the compressor if the above explains oiling/charging does not help, the expansion valve replacement.
Cooling system working principle is as follows: Compressor increases gas refrigerant pressure to a very high level. With this the temperature of the high pressure refrigerant also gets very high. When this high pressure and high temperature gas enters the condenser (at the radiator at front of car) it turns into liquid form when the heat is removed (air flow cools it down). Now at liquid form and still under high pressure the refrigerant flows thru expansion valve. This valve simply is a fixed size hole in the tubing and it separates (like the compressor) the high and low pressure sides of the cooling system. The liquid refrigerant turns in gas form after the expansion valve and causes cooling in the evaporator element, which the air is blown thru inside the car.
If the orifice of the expansion valve would wear out and be too large it could let too much flow thru it and cause some liquid form refrigerant to appear in the low pressure side of the system.
The expansion valve is very low coast item. I have bought 3 of them in the past for some older cars I had and the most expensive of them was $7 + tax. It could cost perhaps even $20 now. Anyway, the problem is not the cost of the part, it is the work to have it replaced because the whole A/C system must be drained. Expansion valve is located inside the A/C tubing right at the break point in line before that low pressure side service port. While A/C is running you can feel this in temperature of the line as the high pressure side of the expansion valve is hot while the low pressure side is cold.
The problem with this work is not the replacement of the expansion valve. It is the re-charging the refrigerant because before that you need to vacuum the system. Vacuuming is necessary because air in the system causes poor performance as air is incondensible gas, i.e. when compressor compresses air it does go to high pressure with high temperature but it does not turn in liquid form in the condenser but remains in gas form and circulates back to compressor taking room from the refrigerant to be compressed. But, you could change the expansion valve and then take the car in an A/C shop just for vacuum and charge.
Arrie
Our 2007 Tahoe has fluctuating fan speed on the ac. It seems especially worse on the middle speed settings. I will be driving along (or sitting at an intersection) and the speed will suddenly go up or down for a few seconds. NOBODY else has this issue?
I took it in twice to the dealer and each time they said the system was fine. I took it back a third time and they said the aspirator was bad. However the problem continues.
Automatic system does change fan speed according to temperature reading inside the vehicle.
A sudden change in fan speed can happen for example if the driver's head is located too close to the air temperature "sampler" intake in the ceiling and suddenly changes distance to the sampler. Help for this issue is to set driver's seat lower so that head is not too close to the sampler intake at any time.
Sounds weird but drivers head being too close to this small "speaker looking" air intake can change air temperature entering inside the tube where temperature is measured. This happened to me and I had to lower my seat down from where I first wanted to have it.
Above assumes that the air temperature measurement is made to work the same way as in '04 Tahoe with automatic climate control.
If your system is a manual climate control and has fixed fan speeds and fan speed suddenly changes you have an issue, which must be fan or fan speed controller related.
Arrie
This is a VERY frustrating problem. I'm likely to be out of warranty by the time next summer rolls around so I wanna get this fixed asap.
They said nothing was wrong the first few times they checked it out. The problem got worse and worse until eventually the max air button would click off on it's own even though we were on manual setting. I brought it in again and they said the aspirator was bad (the thing above your head) so they replaced it. Now the max ac button no longer shuts off on it's own but the brief changes in fan speed have returned. I fear it's some kind of electrical issue with voltage problems on the blower resistor. The problem is that dealers rely on the vehicle computer system when deciding if replacing parts is needed. If there is a problem but the computer doesn't show it (via codes) then the dealer won't do anything to fix.
GM is in so deep mess at the moment they cannot afford fixing vehicles on warranty unless they absolutely have to. Issue like yours, if not absolutely repeated at the dealer's service shop and you having witness with you will not be repaired on warranty but as your warranty goes out I can guarantee they will want to change all kinds of parts on it as it will be done on your dime.
I had to trouble shoot and fix my car myself after the first about 2000 miles when fuel consumption went from 18+ MPG to 13 MPG on highway driving. Dealer claimed there was nothing wrong as there were no trouble codes in computer. I found all sorts of problems the intake manifold leak being the biggest one...and whole bunch of improper electrical connections on wire harnesses...
Good luck with yours.
Arrie
I have been buying "little used" 2 - 3 years old cars before as I am kind of a mechanic and fixing cars for me is easy unless it is a computer issue or something like that.
After years saving money I finally was able to consider buying a new vehicle and it sounded so good not needing to work on it. It cost almost $40 000 to get my hands on this Tahoe LT and then all but trouble. And chevy dealer does not do anything to fix it.
Tail pipe looks like it burns a gallon of oil between oil changes, but it did not and still does not burn any oil. It just sent unburned fuel thru tail pipe as engine was not working at the most effective way and biggest problem with this seemed to be intake manifold gasket leak. Believe or not but it has a lot to do with engine performance as leak changes MAP sensor reading, which is part of controlling ignition timing.
Leaking intake manifold gasket also caused rough or jerking idle.
I also soldered almost all wires to the pins at sensor harnesses. I believe the only one I have not done yet is the crank shaft position sensor wire harness and that is because it is not easy to get to. Starter motor has to be removed to gain access to it.
My Tahoe works quite well now and I still get about 18 MPG with 77 MPH speed on highway. I have 94 000 miles on it.
Last scare was coolant level dropping off but it seems to have fixed itself after I poured some Bar's leak fix in it.
Arrie
I dropped the tahoe off this morning and showed the tech guys how my ac fan speed will go up and down even when parked. They called and said they can't figure it out so they are gonna replace the control head. Well see if it works.
Regards.
Basically, we were looking at at least $1500 in repairs to possibly fix the issue on a truck that's worth $5000 and needs new plugs and wires and new tires. $3000 total. I just can't do that right now. So, DH can suffer his 2.5 mile commute w/o AC for a few more weeks.
Good luck figuring out the issue. I'll check back to see if anyone does find a resolution. The guy who did most of the work for me thinks the tensioner is a piece of crap and Chevy should have made it heavier. FWIW.
I had not heard back from anybody regarding the issue until today.
I am visiting in Europe and have not been able to connect to internet. This is the country with Autobahns and it feels kind of good driving 140 MPH in a car that is made for driving fast...but that is another topic.
If your A/C still blows cold I would let some more refrigerant out. You can do this until you see a drop in the A/C efficiency and then add some back until it works ok again. But before letting more out you might want to make sure you have enough oil in it as oil is lost when you let refrigerant out.
There is another thing to consider too, which I am thinking to do myself to my own Tahoe...replace the expansion valve.
Expansion valve can be a problem as it has a very fine mesh screen with it. Over time the compressor wears and all of the metal dust that it spits out is meant to be caught by this screen on the expansion valve. Well, if this screen gets plugged too much it starts to restrict coolant flow thru it and this could be causing some trouble.
The job includes vacuuming the A/C system before re-charging it.Vacuuming is possible to perform at home too. I have done this in the past a couple of times and it works fine.
For vacuuming the A/C system you need to purchase another charging hose and then cut off the end that screws to the refrigerant can. Then you find a vacuum connection in your car's intake manifold (there usually are plenty of those) and see what size hose you need to get to connect to one of these ports. Then you get a proper size hose and connect it to the charger hose end that you cut the refrigerator can connector off. Now you have tools to vacuum your A/C system before re-charge.
You turn off the A/C system (it should not run without refrigeranr anyway but to make sure turn it off) and start car and run it on idle. When idling the engine generates very high vacuum inside the intake manifold. Some cars over 24". When you connect the hand made hose to the A/C system service port and then the other end to the intake manifold port you will vacuum the A/C system very well. You have it "vacuuming" 15 minutes and it is pretty empty.
After about 15 minutes disconnect the hose from the service port before turning off the engine. Now you are ready to re-charge the A/C system. You will start with a can of oil charge. It will go inthe system without running the engine as the vacuum in the system will pull it in. Then you start with a can of refrigerant and when that stops going in you will need the help of the compressor, i.e. turn on the A/C system for max cooling. This probably will not start the compressor as the coolant level is still so low in the system. To make compressor run you need to short the two wires on the harness that connects to the pressure sensor that is mounted on the side of the dryer bottle.
A new expansion valve is very low cost item. Last one I bought for my Dodge Ram tryck cost $6 or something like that. Expansion valve is located inside the tubing where there is a union on the line just before that dryer bottle. If you run the A/C before the job you can feel the line for temperature as before the expansion valve it is hot and after the valve it is cold.
Arrie
O.k im at 35# refrigerant now, so should i drop it to 25 and add a can of oil and then some refrigerant if it needs it?..Or just put in some oil now at 35?..(My oil cans say they have 2 ounces of oil and 2 ounces of refrigerant)..Id like to try one of these options first before i vacuum the system .Right?.
It should have plenty of oil because before i drained it i added a can to see if it would help...then after it didnt help, i added another can..and it still didnt help...And then it was in the danger zone .(above 60)..so i had to let it out anyway...so i backed it down to 35..
Then what about the oil and freon going into the vacuum line of the intake.That wont hurt anything?.What about a regular shop vac adapted to fit the hose from the end i cut off?
If the air is ice cold at 35 with a ambient temp of 90 ..Then would you still think the expansion valve is restricted?..Seems like it would be noticably warmer if it was restricted since at 90 degrees it recomends 45-55.
I was told to use the 150 vicosity oil..And that the 100 was ford and 46 was dodge..Am i using the correct oil?..Thats what they said at Autozone anyhow..
Thanks for all your time. I really apreciate it
As your compressor already is years old meaning it is not the tightest one I would use higher viscosity oil. It's like with old car engines. High mileage engines benefit from higher viscosity oil as fit between piston and cylinder is not that tight any more.
And make sure you run also the rear seat A/C as it works from the same compressor when you evaluate if it still blows cold or not..
Vacuuming the A/C system using a intake manifold port should not harm anything in the engine. I think the only component that could get harmed from the A/C system oil is the MAF sensor, but this sensor is mounted right after air box in the ambient pressure environment. The only sensors that are in the engine system that would see the A/C oil are the O2 sensors but they see engine oil anyway so I don't think A/C oil would hurt them especially because very little of it will be coming out from the system when you vacuum it.
Shop vac will not provide any real vacuum that would be sufficient for A/C system vacuuming. You either need to use a specially made A/C vacuum, like people working on home systems use (or car systems) or use the car engine vacuum. I have done this on a Lincoln that I had many times when I had problems with seal leaks and also with my Dodge RAM truck when I changed the expansion valve and dryer in its system.
Have you noticed any difference in fuel mileage after you dropped the A/C system pressure?
Why I mentioned the expansion valve as a possible problem is that it can cause it two ways. Either the screen of it can get plugged or the orifice wears out to too big opening.
If it gets plugged it can cause over pressure on the compressor output side and if the compressor is equipped with an over pressure port it can make noise when this port open up and re-circulates refrigerant back to intake side of the compressor. In my Dodge the over pressure valve spits the refrigerant out, which was a clear indication of my expansion valve being plugged, like it was when I finally changed it.
If expansion valve wears to too big opening it can let too much liquid refrigerant thru it on the intake side of the compressor, which is not good. Liquid does not compress so it can cause over pressure in the compressor and be the cause for the noise.
Arrie
bingram
04 Tahoe
Document ID# 1639237
Subject: Buzz Noise From Headliner Above Driver - keywords ac air aspirator cover fan grille HVAC interior microphone sensor speaker temperature vent vibration
#PIT3511 - (03/29/2005)
Models: 2000-05 Cadillac Escalade
2002-05 Chevrolet Avalanche
2000-05 Chevrolet Silverado, Suburban, Tahoe
2000-05 GMC Sierra, Yukon, Yukon XL, Yukon Denali
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
Condition/Concern:
Dealer or customer may comment that they have a buzz or vibration noise emanating from the headliner in an area that looks like microphone or a speaker.
Recommendation/Instructions:
The plastic escutcheon grill, which is round and about the size of a half dollar and located just above the driver to the left, is the interior ambient temperature sensor. The sensor is used in conjunction with the automatic HVAC (C68). On occasions, this sensor has been known to make a buzz or rattle sound. The sensor uses a small fan to pull air over the sensor. This buzz noise may be intermittent.
Although it may not be possible to alleviate all of the buzz or noise from this sensor, Engineering has found that if the sensor is installed incorrectly that it may bind and cause the fan to make a buzz noise. Remove the sensor and while doing so check for any binding. Reinstall the sensor and re-test. If the noise is still present, the sensor itself may be noisy and require replacement.
===
My question is, is this document a TSB or a recall? Does this mean that a dealer would address it free of charge despite being out of warranty? Mine is a 2005 Yukon XL. I can't seem to find this on any official GM site, and I'd like to have something to back me up when I go to the dealer. From what I've gathered, they will charge about $60 for the part plus an hour of labor. I'm having no luck finding this one GM's own website. Thanks for any help.
In that Pontiac blower fan speed control is done with resistors, i.e. with each fan speed the voltage to the fan motor goes thru a different resistor, which drops the voltage for the motor for a set fan speed. Resistors are located in the air flow duct by the fan, i.e. the resistors that heat up as they lower the voltage are cooled by the air flow that the fan makes. This is why it is the lower speed resistors that usually fail because the air flow is lower. I also think there are more than one speed connected in series so when just one of those burns it takes all of the speeds out that are in that series. I also lost lower 3 fan speeds when it happened.
As I said above this writing is with a Pontiac Grand Am but I would not be surprised if your Tahoe would have exactly the same construction for blower fan speed control so look at the air duct around the blower. You might find a small circuit board bolted in the side of it, which has those fan speed resistors built into it. You can probably buy a new one at car part store other than a dealer just as I was able to for My Pontiac.
Arrie
So - should I add coolant to the A/C system and if so - what and how?
Thanks!
Well, regardless of the age you might have lack of oil lubricant in your A/C compressor,
If the belt "flaps" it probably does it at frequency of pistons moving in the compressor. This would mean that your compressor causes more than normal torque peaks as it turns around.
Unless you have severely over filled you A/C system the first thing I would do is to get a small bottle of A/C lubricant and fill it in and see if it helps.
If you are a little bit hands-ON person go get a A/C kit with refrigerant, oil fill and pressure gauge. These are not expensive and can be found in any car parts store.
First measure pressure by the instructions with the gauge, i.e. run engine with A/C ON for a few minutes and connect gauge on the low side service port (it should not even fit on high side where you NEVER want to connect). Low side service port is in part of the line that gets cold.
If pressure is not too high add oil lubricant again in the low side service port and see if it helps.
If the pressure is too low add refrigerant but you say it works fine, i.e. refrigerant fill should be good and low fill should not cause too high torque on the compressor anyway.
Over filling the system can cause this issue, i.e. you would have A/C refrigerant entering the compressor in liquid form, which does not compress and would cause very high torque pulse. This can cause severe damage to compressor too.
Arrie
Thanks
Hope this helps you.
I own a 2000 C1500 Suburban.
HVAC equipment is C60 (front, manual control) and C69 (rear, manual control)
As I can find easily used controls on eBay, is there any way to simply upgrade my AC to electronic control? Is wiring pin to pin compatible?
Olivier (from France)
I usually run the front AC on the mix setting where it's blowing through the dash vents (not the defrost vents) and the under dash vents with the air set to recirculate. When using this setting, and the fan is at 2 or higher, all front dash vents work normally. If I switch the fan to 1, the vent in the center of the dash (by the radio) stops blowing air. This just started. I know there are actuators under the dash but why would one change it's configuration just because I changed the fan speed? The only other explanation I can imagine is that he actuator won't move fully into the proper position and the fact that the air speed is lower on 1, it doesn't generate enough air pressure to pass the actuator. Any advice would be much appreciated.
Thanks in advance,
Jeff
i have checked all of the fuses hoping that it might be that but they all seem to be just fine. thanks for the help,.
Vehicle: 2002 Chevy Tahoe with climate control
Problem: AC ran full blast constantly (when set to auto)
Replacing the aspirator as described in this thread fixed the problem.
I bought the part( pn: 25903301 ) online from GM Parts Direct for $24, shipping and handling was another $13. I did find the part online at another vendor for the same price but $5 bucks less in shipping. But I placed the order with GM Parts Direct since they had done the legwork regarding the part number. They were prompt and efficient; delivery took 5 days.
Installation took me about 30 minutes after doing some reading on how to "loosen" the b-pillar. It turns out you just give it a tug straight out. It snaps on and off. Finding some online notes on how to replace the headliner gave me the confidence to just pull on it. It was tight quarters to get at the aspirator to replace it but doable.
The boss tells me her AC works great now so I'm very pleased with how this repair went.
Frank
P.S. Our Tahoe has been very good to us and we hope to get several more good years from it. It has 97,000 miles on it and the only significant repairs have been a new fuel pump and some substantial rear brake work. (knock on wood)