Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Chevy Suburban and Tahoe AC and Heater Problems



  • treedogtreedog Posts: 12
    Hey Arrie , Glad your having fun...I have a European friend that would love to bring his BMW back from Florida and drive it on the Autobahn...

    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) i had to let it out 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
  • arriearrie Posts: 312
    If you added two cans of oil at first then I think you can let some more refrigerant out and like I said you will see when you are too low as your cooling will start suffer.

    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.

  • jl222jl222 Posts: 1
    i have an 05 tahoe with the same problem, blowing from the defrost. I was going to buy a new replace the controller but wanted to see if you resolved your issue another way? Winter is coming and my heat does not work either! :(
  • ahightowerahightower TXPosts: 539
    A little late to this dicsussion, hope someone is still watching. I started to get the buzzy sound from the aspirator. Quite annoying. I pried off the cover and blew out all the dust and sprayed in some WD-40. I don't think it did any good. I guess it's time to replace it. I'll let you all know if I succeed in that. I was able to access it by partially removing the weather stripping and the A-pillar trim piece, but I could barely get the plastic cover back on, there was not much "give" in the headliner and it was very difficult to reach the aspirator just to hold it still and get the plastic clips back in for the little cover/grille thing. Perhaps if I unscrew the thing holding on the sun visor that will provide more room to work. I would like to try it myself. If I can't do it, then I'll take it to the dealer and let them use the part I already bought. Anyone else done a DIY on this thing yet? Or, better yet, do I really need to replace this thing? Why is it buzzing anyway, does it need a good cleaning or is the little electric motor dying on me?
  • I have an 02 Surburan with an air flow control problem. When I turn the control knob to change the air flow direction ( ie from heat to defrost ) it does not change direction. The only place air blows is out of the dash outlets. Does anyone know what the fix would be?
  • I might have a solution for some of you that had the climate control fail to defrost mode only, after I replaced the battery. I tried several things that I read about on different forums and while I was playing under my dash I bumped my Power Seat switch. To reset the seat position, I pushed my Driver preference button and my Climate Control defaulted to my old setting and is now working.

    04 Tahoe
  • ahightowerahightower TXPosts: 539
    Regarding the buzzing aspirator, I've come across the following in a couple other forums:

    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.

    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.

    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.
  • ahightowerahightower TXPosts: 539
    I bought the part from my GMC dealer for $44 + tax and installed it myself in 10 minutes. Just remove the visor (left side only, and you'll need a torx driver, not philips), gently loosen the A- and B-pillar trim, pull back the weatherstripping, and you're in. Pop the grille off with a flat screwdriver, have your lovely assistant gently pull down on the headliner so you have room to work, and then simply unplug the old aspirator and plug in the new one. Snapping the little grille back on was a little tricky. But it's done and it's silent and as far as I know it works. We'll be going to Marble Falls, Amarillo, and Houston over the coming holidays, and I would have gone insane listening to that for 1500 miles! Also glad I didn't wait around the service shop and pay for an hour of labor.
  • I have an 2003 and my blower is only working on setting 4 and 5. It is blowing at what it would for these two settings. At 0 to 3, the air is just lightly flowing though the vents. What could the problem be?
  • My climate control is only working on the settings of 4 and 5. from 0 to 3 the air comes through as a breeze. What could be the problem with my system? The blower is working at the correct strength at both 4 and 5, and the rear blower is working just fine in all settings.
  • arriearrie Posts: 312
    I had the same problem with a '02 Pontiac Grand Am and it was caused by burned out blower speed control resistor.

    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.

  • beckya1beckya1 Posts: 1
    Hi - I need to know if I should add Freon (or the alternative) to my A/C system on my 1999 Tahoe. The past 2 seasons the A/C has become progressively 'less' cool. I turned it on the other day when it was only about 65 degrees out and it didn't cool at all. It wasn't blowing hot air - it was just blowing.

    So - should I add coolant to the A/C system and if so - what and how?

  • ackingacking Posts: 6
    With the engine off, turn your compressor clutch by hand and make sure that you don't have any tight spots. The problem could exist from a compressor that might be ready to sieze. Also have the air conditioning tested to ensure that the charge levels are good, overcharging a system could lead you on a wild goose chase of strange noises.
  • ackingacking Posts: 6
    Only use virgin R-134a refrigerant. Drop in refrigerants aren't such as dura-cool aren't really safe for A/C systems. Always refer to manufactures spec!
  • arriearrie Posts: 312
    What age is your car?

    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.

  • zigfreedzigfreed Posts: 1
    Did you ever figure out the Air flow problem on your suburban, I am having the same issue.

  • I did find out what it was. It is a fan blower resistor. It is located under the glove box. It is extremely easy to fix. I was only able to find the part from GM. Napa did not have it and could not get it for my model year. It took me maybe 10 minutes to take the cover off and switch the part out.
    Hope this helps you.
  • suburban68suburban68 Posts: 3
    Hi all.
    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) :D
  • I had the same problem. I replaced the ac compressor ( rebuilt) and work good its been about 1 year ago, i did the repairs my self, I spend about $200.00
  • sulli031sulli031 Posts: 1
    I have a 2002 Tahoe and the fan works on blower settings 1 - 4 but shuts down on setting 5. Any ideas what's wrong and how to fix? Thanx.
  • My 1999 Suburban blows warm AC in the front, and ice cold air in the rear. It also does not have the lower fan speeds, most of the time they are not working, but intermittently they will work, while the high speed position works most of the time. I think this problem might be a bad fan control resistor, but I am not sure how it would impact the front AC operation. Any suggestions?
  • I have the same problem on my 1999 tahoe did you find the problem?
  • bamahoovbamahoov Posts: 1
    I have a 04 Tahoe, and its doing the same thing with the AC. The front vents blow hot ait, but the back vents blow out cold air. What the deal? Thanks guys.
  • Problem fixed. I went down to Walmart, bought a 22oz can of R134 freon with oil and sealant in it. I turned on the Suburban, put the AC in max high, heard the AC clutch engage, disengage, engage, disengage, a sure sign that the freon is low. I had two ports to choose from, only one is small enough for the coupler to snap over. I blew some freon through the hose as I connected it to push any air in the hose out. I squirted freon into the system until the AC compressor quit clicking on and off. Then I continued to squirt until the pressure was in the low range on the gage for the given outside air temperature. The instructions for this are right on the can, it is a no brainer to do this! I used almost the whole can. Towards the end of the recharge the cheap hose connection started to leak, so I disconnected. But it was a good enough recharge that the Suburban has cold air in front and in the rear. I still have a bad fan switch problem that remains unsolved. I think we have low and high, but nothing in between.
  • I have an 02 Tahoe LS 2WD. Something weird has been happening lately. I've searched through a lot of the posts in this thread and haven't seen this issue exactly.

    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,
  • z7onez7one Posts: 1
    i have read some post on this site with people having the same problem but i have not found the answer yet. the front climate control is working just fine with the heat , ac , defrost, ect... the problem is that nothing at all is working for the rear climate control. if anyone has the answer that would be great or even just a starting point.
    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,.
  • frankd28frankd28 Posts: 1
    This thread saved me some time and money so I thought I post my experiences in case it may help someone else.

    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.


    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)
  • Anybody remember how much PAG 150 oil to put in the compressor when you change out the AC parts. Thanks in advance for the help
  • By the way the vehicle is a 1994 chevy suburban with rear AC, thanks.
  • e7boatse7boats Posts: 1
    Dash A/C Blows cold. Rear Blower works, air flow is correct, and rear evap is cool but not cold. Anybody got any ideas what the problem could be?
Sign In or Register to comment.