a/c help
Thread Starter
Instructor
Joined: Sep 2000
Posts: 130
Likes: 9
From: Montgomery TX
a/c help
I am having a small (big) problem with the a/c. The a/c blows cold and works great except when I first start it up. It will take up to five (5) minutes befor the air blows out of the dash or floor vents. It blows cold air through the defroster vents for a long time at first. This happens on any selection , auto or other, of the controls.
Thanks in advance for solution....
Thanks in advance for solution....
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
This sounds like the famous vacuum line check valve problem...but I am not 100% sure if your engine had the same thing as the LT1 and earlier cars.
Aside from that,there are plastic vacuum lines and theres a check valve on the lines on the side or back of intake manifold,depends on engine,year,etc and it looks like a 2-3 way funnel,its very small,and when they stick or go bad,the a/c will blow out the defrost most of the time or take a long time to switch over.Just wanted to share that info in case it is a vacuum problem with the check valve.
Im sure someone will post tonight or tomorrow to aid ya more.I seen your sig and it says an LT4 so be sure to include your correct engine year and info. If I assumed wrong.
Aside from that,there are plastic vacuum lines and theres a check valve on the lines on the side or back of intake manifold,depends on engine,year,etc and it looks like a 2-3 way funnel,its very small,and when they stick or go bad,the a/c will blow out the defrost most of the time or take a long time to switch over.Just wanted to share that info in case it is a vacuum problem with the check valve.
Im sure someone will post tonight or tomorrow to aid ya more.I seen your sig and it says an LT4 so be sure to include your correct engine year and info. If I assumed wrong.
Safety Car
Joined: Jul 2004
Posts: 3,845
Likes: 30
This sounds like the famous vacuum line check valve problem...but I am not 100% sure if your engine had the same thing as the LT1 and earlier cars.
Aside from that,there are plastic vacuum lines and theres a check valve on the lines on the side or back of intake manifold,depends on engine,year,etc and it looks like a 2-3 way funnel,its very small,and when they stick or go bad,the a/c will blow out the defrost most of the time or take a long time to switch over.Just wanted to share that info in case it is a vacuum problem with the check valve.
Im sure someone will post tonight or tomorrow to aid ya more.I seen your sig and it says an LT4 so be sure to include your correct engine year and info. If I assumed wrong.
Aside from that,there are plastic vacuum lines and theres a check valve on the lines on the side or back of intake manifold,depends on engine,year,etc and it looks like a 2-3 way funnel,its very small,and when they stick or go bad,the a/c will blow out the defrost most of the time or take a long time to switch over.Just wanted to share that info in case it is a vacuum problem with the check valve.
Im sure someone will post tonight or tomorrow to aid ya more.I seen your sig and it says an LT4 so be sure to include your correct engine year and info. If I assumed wrong.
Thread Starter
Instructor
Joined: Sep 2000
Posts: 130
Likes: 9
From: Montgomery TX
check valve
Thanks for the replies, Yes I do have the LT4 engine.
I did change the little three way check valve under the right side injector cover last month thinking that it would solve the problem as it was broken. I appeared to work a little better but still has a problem. I'll check the shop manual for other areas.
Any other replies will help
I did change the little three way check valve under the right side injector cover last month thinking that it would solve the problem as it was broken. I appeared to work a little better but still has a problem. I'll check the shop manual for other areas.
Any other replies will help
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Still sounds like a Programmer defect. System is designed to purge air on startup through the heater ducts to prevent window fogging. Shouldn't take forever. Programmer controls that - it's the Processor - and it gets it's signals from the Dash Controls over serial data lines. There is nothing in those signals (that I can think of) which would make it act the way you describe it. Since you've verified that vacuum is good in the engine compartment, you need to make sure it's good at the Programmer. Assuming it is, I'd pop for a rebuild.
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