Last post on Nov 18, 2013 at 7:10 PM
You are in the Chevrolet Suburban & Tahoe
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Chevrolet Suburban, Chevrolet Tahoe, Chevrolet Tahoe Limited/Z71, SUV
#98 of 372 Re: AC / Heat Noises 2002 Chevy Tahoe [treedog]
Aug 28, 2008 (1:56 pm)
Hi there treedog,
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.
#99 of 372 Re: AC / Heat Noises 2002 Chevy Tahoe [arrie]
Aug 29, 2008 (5:29 pm)
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)..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
#100 of 372 Re: AC / Heat Noises 2002 Chevy Tahoe [treedog]
Aug 30, 2008 (4:50 am)
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.
#101 of 372 Re: Chevrolet Suburban & Tahoe: A/C - Climate Control Questions [ge_cco]
Oct 26, 2008 (9:10 am)
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?
Nov 19, 2008 (6:40 am)
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?
#103 of 372 climate control problem after battery change
Nov 19, 2008 (8:55 am)
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.
#104 of 372 Aspirator - TSB/recall?
Nov 22, 2008 (1:34 pm)
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.
#105 of 372 Re: Aspirator - problem solved
Nov 26, 2008 (4:29 pm)
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.
#106 of 372 Re: Chevrolet Suburban & Tahoe: A/C - Climate Control Questions [tidester]
Dec 04, 2008 (4:39 pm)
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?
#107 of 372 climate control on '03 suburban
Dec 04, 2008 (4:51 pm)
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.