Last post on Jan 29, 2013 at 2:06 PM
You are in the Chevrolet Blazer
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Chevrolet, Heating / Cooling, SUV
#75 of 154 Re: 2002 Chevrolet Blazer heater problems [juliemact]
Apr 30, 2008 (6:45 pm)
Julie, there is an air mix damper in the ductwork under the dash. I haven't had to work in this area, but it does sound like it could be your problem. These vehicles do not have the conventional heater control valve, so water is always flowing through the heater core. Anybody who has done work on this feel free to jump in here.
Curious about the temp gauge, though. When you start from cold, the gauge will go up just above normal for a minute or so, and then should drop back to normal. What this indicates is the point at which the thermostat opens.
#76 of 154 Re: 2002 Chevrolet Blazer heater problems [jlflemmons]
May 01, 2008 (8:09 am)
Thanks for your reply, I'll look into the damper. The temperature gauge has been going higher than it normally does, more like it's about to overheat, until I hit the interstate and begin to accelerate, then it lowers back to normal.
#77 of 154 Re: 2002 Chevrolet Blazer heater problems [juliemact]
May 01, 2008 (3:07 pm)
I know this sounds stupid, but are you sure the cooling system is full? Each of the issues you discribed can also show up with air in the cooling system. When you accelerate hard, do you hear gurgling in the area over under the glove box (heater core)?
May 06, 2008 (4:38 pm)
I bought my 2000 4.3L Blazer in 2003 with 38,000 plus miles on it. Since then, I have replaced the heater core, door bushings, front driver locking mechanism, idler arm, shocks, but didn't even bother replacing those poorly made front reclining handles on the driver and passenger seats.
Now, my A/C isn't puttin out cold air, so I had the shop do a test and refill the freon a couple weeks ago. A week later, there is no more freon, so I take it to another shop. They do a leakage test with dye in the freon and can't detect anything in the engine comparment... and they said it is most likely the Evaporator Core behind the dash... and this will cost almost $1000 to replace. Is this really the problem, or is this shop blowing "hot air"? Also, it is even worth it to replace?
#79 of 154 Re: A/C Problems... [truly_genwine]
May 06, 2008 (5:52 pm)
First of all it is probably not the evaporator. Are you sure the freon is gone? If it is not, the blend door that mixes hot and cold air may not be moving properly. This is a common problem. Sometimes the actuator fails or the hinge is not working right. Get the parts catelog pictures from the dealer and try to verify the door is moving to the correct positions for heat or A/C.
Most of the time the freon leaks are from the hoses, O rings and fittings but......
If you suspect the evaporator, have the freon drained at the AC place and see if you can attach some fittings to the evap inlet and outlet to do a pressure test to see if it leaks. You don't have to take it off if you can attach some hoses or fittings As far as I know the evap. is bolted to the firewall with 4-5 bolts or nuts and can be removed yourself with out getting under the dash. Then you could have it checked with the dye and UV light. If it's bad you could either buy a new one or get a used one from the junk yard that doesn't leak. In either case it's no where near $1000.
If the evap is OK check to see the clutch to the compressor isn't slipping. When the bearing goes bad after 90,000 miles it ejects ball bearings which get trapped in the clutch until they disintegrate causing the clutch to slip.
Also you might want to check the receiver-drier. It acts as a filter to the system and if it gets plugged up then the freon dosn't go to the evap as much as it should. They don't cost much and are easy to replace.
Hope this helps
#80 of 154 Re: A/C Problems... [dfhltd]
May 06, 2008 (7:39 pm)
First off.. thanks for the 411.
I know a few things about cars... but mostly because of whats been replaced... other than that... you don't want me around to help... haha.
Heres the thing. I took it to one shop just to do a basic test and add freon... and it worked fine for a little bit. I had no need for A/C until a week later, and found it wasn't working. So I took it to another shop, and they did the same tests, and added more freon... this time adding dye to it, and they didn't find any leak in the engine compartment. The shop owner suggested that it was the Evaporator Core and it needed to be replaced... for almost 1k.
I have a cousin that could help me if I can dial in the primary issues... but don't really know if I should take what the mechanic said as the truth.. or a waste of time. I want to take it to a 3rd place... but these A/C tests run 70 dollars plus every single time.
What do you think???
#81 of 154 Re: A/C Problems... [truly_genwine]
May 07, 2008 (4:29 am)
Have them recharge and "soap test" (literally use soapy water) around the top of the compressor where the two aluminum pipes (manifold) connect. There are two little high pressure seals in there that will flatten and leak over time.
I had this exact same problem on my '99 model. Couldn't find a leak anywhere, and then of all things, my son could actually hear the soft hiss of the leak! Nothing wrong with that kids hearing!
The seals are about $5-$10 each, takes about five minutes to replace, but then the system needs to be evacuated (vacuum draw down) and recharged. Hope this helps you out. Definitely cheaper (and a whole lot easier) than changing the evaporator core.
#83 of 154 Loss of heat-overheating
May 10, 2008 (7:12 pm)
Hey! Help would be much appreciated from anyone who can help....
My '99 2DR Chevy Blazer has already had a new water pump installed...just about 5 months ago. About 3 months ago, (during the COLD of PA winter...haha) I noticed that my heater was not working. It seems when I am driving about 55 mph or less, it just will not work, and then the temp shoots up to about 240. However, my drive to work is about 45 minutes, and a good portion of that is on an interstate with a speed limit of 65. When I am going that fast, the temp drops down, and magically I have heat again. When it first happened back in probably January, my husband replaced the thermostat (easy fix) and it worked like a charm until probably about late March. Then the same thing started happening again. Any ideas? I would be very appreciative!!! Thanks!
#84 of 154 Vent Control Problem with '88 S10 Chevy Blazer
Jun 28, 2008 (5:26 pm)
The heater/AC on my '88 S10 Chevy Blazer blows hot/cold air well. However, when I adjust the selector to any of the AC choices, the air only blows on the floor rather than
the dash vents.
I've checked to see that the 2 vacuum hoses are connected to the heater/AC diaphragm on the floor. Maybe the other ends aren't connected.
1. Could this be the reason that the baffles don't adjust to bring the air to the dash vents?
2. If so, is there a diagram showing their location on the other side of the firewall?
3. Is there a handy "how to" cheat sheet to disassemble/reassemble the heating/AC system if it turns out that the diaphragm is bad?
My Chilton manual is lacking any information on how to troubleshoot this problem,
Thanks a million,