All, I have a question about the factory air conditioning in my '86 K5 Blazer. My truck's ac does blow cold air, but compared to modern day trucks, my truck just doesn't move air around worth a dang. All air conditioning components (hoses, evap, pump, etc) are new and working, and it keeps charged with coolant (doesn't leak). However, the ac system just doesn't cool the driver and passenger. I remember back in the day that these trucks would freeze your @ss off if left on full blast cold. So, why is my truck not cooling me off the same way? All speeds of my blower work. Is it possible that the air ducts in the dash have rotted/cracked and dumping air into the dash? Can someone suggest some possibilities here?
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
K5 Blazer Factory AC Question...
- Thread starter PWagon
- Start date
Dedles1
Registered Member
I've never had the a/c work in my truck, so i dont know how well it should be blowing. but you can check the ducts and make sure they are together and not clogged up with anything. Also check the air vent door by the pass side foorboard and make sure it is opeining properly.
herkdriver007
1/2 ton status
I'm going to assume its 134 refrig vs r12? That will have a big impact on the cooling factor... Are you sure it's not the blower?
Jessie James
1/2 ton status
FWIW
My compressor seized so I had my local mechanic replace it. I am not sure if he converted the refridgerant, but I am sure it's whatever the most modern is. He also replaced something else, maybe the condenser? I'm not sure. But it cost about $1k.
My diverter door cable is broken, so the air blows out of all vents at the same time (defrost, dash, floor) but my kick panel recirculate door works if I put it on "Max A/C".
When the A/C in on my truck gets ice cold in 110 degree weather in about 5 minutes.
My compressor seized so I had my local mechanic replace it. I am not sure if he converted the refridgerant, but I am sure it's whatever the most modern is. He also replaced something else, maybe the condenser? I'm not sure. But it cost about $1k.
My diverter door cable is broken, so the air blows out of all vents at the same time (defrost, dash, floor) but my kick panel recirculate door works if I put it on "Max A/C".
When the A/C in on my truck gets ice cold in 110 degree weather in about 5 minutes.
British Slave
1/2 ton status
- Joined
- Jul 25, 2007
- Posts
- 2,086
- Reaction score
- 2
You need to check the mode door to see if it is closing all the way. That seperates the heating and cooling. There are two vacuum motors on that door. One isolates the evaporator when in heater mode and the other closes the heater core off when in AC mode. It not real uncommon for the door to be broken at the pivots. If it is broken, good luck finding a used door.
There are so many possibilities. Without being there, its hard to say. But, you can condense them down into three really broad areas.
Too much heat getting in, not enough heat being sucked out of the air, or not enough air flow.
The heat getting in part is simple. Got a window open or lots of air leaks? Probably not, because that sort of thing is usually obvious.
Not enough air flow is obvious too, as long as you have something to compare it to. If you could find another blazer of the same vintage that the air worked good on, you could turn that fan on high and see if it seemed to put out more than yours.
Without that, its hard to be sure.
But, there is a test that will tend to show that and also address the second possibility of not enough heat getting sucked out.
You need to get a small thermometer. It needs to be fairly accurate and give good resolution.
You should be able to read it down to one degree at least. There are lots of cheap little stick type digital thermometers out there. Any refrigeration parts house should have one.
They are pretty fast acting.
Get one, and go out on a medium heat day. Not a nice cool morning, and not high noon when the asphalt is melting.
Crank it up, and maybe drive around a few minutes so that the engine is warmed up and the AC has had time to reach its best effort.
With the fan on high, and the engine at a fast idle or faster, if you have someone else with you, you can do it while driving, you need to take two readings.
If you can get to the intake of the airconditioner, you need to measure the temperature of the air going into the cooling chamber.
Or as close to it as you can. Somewhere down around the floorboards.
Give the thermometer time to steady down, and then note the reading.
Then, stick it in the vent closest to the cooling chamber, and let it stabilize again.
The important number is the difference between the two readings. NOT the temp of the cool air.
In home ACs, the target number is 20 degrees. In cars, if I remember right, its closer to 40 degrees.
But I did not get a lot of sleep last night, and I may be off. Hopefully someone else will chime in and verify/correct me.
Either way, if the air temp is colder than than, or if its approaching 35 degrees or so on a warm day, then you are not moving enough air somehow.
Either the fins on the evaporator are clogged up, or the air is not getting out into the cab and is going around and around the dash.
If its not cold enough, then the unit is not taking the heat out like it should. You need to get someone to put a set of gauges on it to see why.
It doesn't have to be low on gas, the compressor might be worn and not pumping like it should, or the condenser might not be getting enough air flow. Stopped up with dirt and bugs perhaps.
Too much heat getting in, not enough heat being sucked out of the air, or not enough air flow.
The heat getting in part is simple. Got a window open or lots of air leaks? Probably not, because that sort of thing is usually obvious.
Not enough air flow is obvious too, as long as you have something to compare it to. If you could find another blazer of the same vintage that the air worked good on, you could turn that fan on high and see if it seemed to put out more than yours.
Without that, its hard to be sure.
But, there is a test that will tend to show that and also address the second possibility of not enough heat getting sucked out.
You need to get a small thermometer. It needs to be fairly accurate and give good resolution.
You should be able to read it down to one degree at least. There are lots of cheap little stick type digital thermometers out there. Any refrigeration parts house should have one.
They are pretty fast acting.
Get one, and go out on a medium heat day. Not a nice cool morning, and not high noon when the asphalt is melting.
Crank it up, and maybe drive around a few minutes so that the engine is warmed up and the AC has had time to reach its best effort.
With the fan on high, and the engine at a fast idle or faster, if you have someone else with you, you can do it while driving, you need to take two readings.
If you can get to the intake of the airconditioner, you need to measure the temperature of the air going into the cooling chamber.
Or as close to it as you can. Somewhere down around the floorboards.
Give the thermometer time to steady down, and then note the reading.
Then, stick it in the vent closest to the cooling chamber, and let it stabilize again.
The important number is the difference between the two readings. NOT the temp of the cool air.
In home ACs, the target number is 20 degrees. In cars, if I remember right, its closer to 40 degrees.
But I did not get a lot of sleep last night, and I may be off. Hopefully someone else will chime in and verify/correct me.
Either way, if the air temp is colder than than, or if its approaching 35 degrees or so on a warm day, then you are not moving enough air somehow.
Either the fins on the evaporator are clogged up, or the air is not getting out into the cab and is going around and around the dash.
If its not cold enough, then the unit is not taking the heat out like it should. You need to get someone to put a set of gauges on it to see why.
It doesn't have to be low on gas, the compressor might be worn and not pumping like it should, or the condenser might not be getting enough air flow. Stopped up with dirt and bugs perhaps.
