1998 A/C air flow reduces to almost nothing

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1998 A/C air flow reduces to almost nothing

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Chevrolet >> Chevy Trucks, Vans & SUV's >> Silverado >> 1998 A/C air flow reduces to almost nothing

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1998 A/C air flow reduces to almost nothing - 4/9/2008 4:25:32 PM

king

Posts: 1
Joined: 4/9/2008
Status: offline

The a/c in my 1998 Silverado works great for about 20 minutes. Then the air flow out of the vents goes down to almost nothing. The fan is still running. Switching the fan to high makes lots of noise, but almost no increase in air flow. I switch to defrost and other settings and there is very little air from those vents either. I notice that when I shut the truck off, there are always several gallons of water (estimated, but lots in any event) that drains from the expansion coil drain on the firewall. I speculate that a high level of water is building up in the coil enclosure and is somehow blocking air flow thru the coil. Is this possible? How would I fix this?

Post #: 1

RE: 1998 A/C air flow reduces to almost nothing - 4/9/2008 5:28:30 PM

northey87

Posts: 874
Joined: 10/17/2007
Status: offline

Welcome to the forum!!! Sounds possible. Never done much with AC, but someone here should be able to help, just hang in there.

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''''95 1500 Silverado, 350, flowmaster Force II exhuast, S&B CAI.

(in reply to king)

Post #: 2

RE: 1998 A/C air flow reduces to almost nothing - 4/11/2008 1:36:56 PM

pegleg45

Posts: 1
Joined: 4/11/2008
Status: offline

check ALL your vacuum lines under the hood. especially around the firewall near the master cylinder and by the steering column, or where all the wires go through the firewall. i had this problem once and it was a loose vacuum line. the a/c dampers for the air flow is controlled by vacuum.

(in reply to northey87)

Post #: 3

RE: 1998 A/C air flow reduces to almost nothing - 4/11/2008 2:35:18 PM

northey87

Posts: 874
Joined: 10/17/2007
Status: offline

pegleg45, welcome to the forum!!!

_____________________________

''''95 1500 Silverado, 350, flowmaster Force II exhuast, S&B CAI.

(in reply to pegleg45)

Post #: 4

RE: 1998 A/C air flow reduces to almost nothing - 4/11/2008 3:25:15 PM

RonH

Posts: 420
Joined: 1/31/2007
Status: offline

This also sounds like the system is freezing up. When it does this, what happens if you turn the system over to heat and put the blower to high? Try this next time and turn the dash vents on. If the system is freezing up, you will get a lot of vapor blowing out of the vents in just a few seconds as the heated air thaws the ice, and the flow will be back full strength in just a little bit.

Freezing would also explain all the water draining out, especially if it takes a long time (ice thawing out)

(in reply to northey87)

Post #: 5

RE: 1998 A/C air flow reduces to almost nothing - 4/11/2008 5:31:00 PM

Flying Low

Posts: 30
Joined: 3/15/2008
Status: offline

I had a similar problem with my '97. Turned out to be a VERY dirty coil. Pulled the blower out and cleaned ten years of dirt off the face of the coil, cured my problem.Fairly easy to do.
(Probably would have been a good place to put a filter.)
I also believe the dirt was holding the condensation and freezing.
David

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