AC with slow leak

[kc8adu]

1
i bet you are confused with the muffler on the discharge side of the compressor.it will get hot
the accumulator on these trucks is an aluminum cylinder connected to the evaporator and has a pressure switch for clutch cycling.it should be cold and sweaty.
5.
yes your heater may be on and fighting the ac.esp if there is lots of condensate coming from the front.
another way to prove this is eithe start wih a cold engine and see if the front is cold till the engine warms up or pinch the heater hose and see if it cools down.thre is flow all the time on these trucks so a blend door problem can do this.

 

[KC Strip]

To be honest, daman, I'm not 100% sure if the orifice tube was replaced. I kind of doubt it, though. So my guess is that I should definitely get a new one/have a new one put in.

What does a typical engine fan clutch run/cost?

 

[KC Strip]

kc8adu -

Very little water on the ground from the front. When the rear air is on, there is lots of water back there on the ground. Not sure what that means for the front.

 

[KC Strip]

How do you know if the fan clutch is worn out or need replacement?

 

[daman]

Quote:

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How do you know if the fan clutch is worn out or need replacement?

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At high ambient temps, airflow over the condenser is crucial to good performance. Most fan clutches have 2 stages of "drive". The first stage is the "fluid coupling", which depends on a fluid inside the clutch with a viscosity that changes with temperature. The second stage involves a bimetallic spring (like in a household thermostat) To mechanically decrease the clearances in the clutch, which causes higher fan speeds.

Just like the oil in your crankcase, the fluid in the clutch breaks down with use. it "shears" the high viscosity fluid, and it becomes thin - no longer driving the fan well. This also affects the "locked" performance of the fan, since most new fans do not actually incorporate an actual mechanical lock. With the fluid thinned way down by wear and heat, it is also more prone to leak out of the clutch assembly.

The first sign of failure, is less noise - especially on cold start up. On a cool morning the fan should make a racket for a few seconds at least. If it spins with a fingertip when cold, it is shot. When the vehicle is left to idle on a hot day with the A/C on, it should "lock" the fan clutch within 3 minutes or so. Again, when you accelerate away from that long stoplight, you should hear the fan roaring.

Just because a vehicle does not overheat, does not mean that the fan clutch is operating correctly, a fan clutch usually only lasts to about 50,000 miles then it gets "tired".

 

[daman]

Quote:

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What does a typical engine fan clutch run/cost?

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Sorry,,no there not that much very reasonable..

 

[KC Strip]

Thanks for the tell tale signs of the need for a new fan clutch.

Two more questions - thermal or non-thermal? What about severe duty?

 

[daman]

Quote:

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Two more questions - thermal or non-thermal? What about severe duty?

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[KC Strip]

Sorry - I was referring to engine fan clutches. I noticed online today that there are thermal and non-thermal fan clutches as well as severe duty ones. Anyone know anything about the differences?

 

[daman]

Ask you GM dealer whats what...when i replaced mine
years ago i just got it from GM..

 

[KC Strip]

Okay. Will do - and thanks again!!

 

[daman]

yup, good luck.

 

[KC Strip]

Any thoughts that my problem might be the evaporator?

BTW - the AC does not cool at all (front or rear). It's scheduled to be worked on tomorrow by the same folks who installed the compressor a while back.

 

[daman]

The problem is without pressure readings with Ambient temps
you really don't know what's going on.

hopefully they can find somthing for ya..

 

[daman]

Did you check out your clutch fan??

 

[KC Strip]

I checked, but I wasn't completely sure.

 

[KC Strip]

According to the shop today, the valves were leaking - so those were replaced. They looked for leaks elsewhere and found none. They also checked the rear ac lines and to their amazement the lines were in good working order. Hopefully this solves the problem, but you never know.

 

[daman]

You talking low and high port(valves) where you attach
your hoses???

 

[KC Strip]

"High Side Service Valve" & "Low Side Schrader Valve"

Ever heard of those? That's what they replaced (or at least what they're calling them.

 

[daman]

Yes sir,

well hope that was it, good luck.