1997 Buick Lesabre problem

[rogerwa]

I bought a 97 lesabre for my kids to drive a few months ago. This was a mint condition grandma driven car with the venerable 3.8lv6.. The kids just about craoked when I picked it out as it is not the most stylish thing in the world. It soon earned the nickname of the "the couch" which was shortened from "the rolling couch".

Anyhow it only has one problem that I can find. When the AC is on and you stomp on the gas, the fan output cycles to the defrost ports and then as you get up to speed, it cycles back to the dash vents.

Any clue as to what might cause this?? I believe this to be some vacuum problem, but looking for a more expert opinion..

 

[GA_Boater]

Re: 1997 Buick Lesabre problem

Purely a guess here, but it sounds like your vacuum canister is leaking or the hose to the canister is cracked. I agree that it sounds like a vacuum problem and any vac. hose could be causing this. Get a propane torch and open the valve - DO NOT light it! With the engine idling slowly move the tip of the torch over the hoses under the hood. If the idle speed increases the tip of the torch is at the leak. Good luck - vacuum leaks are a bear.

 

[waterinthefuel]

Re: 1997 Buick Lesabre problem

I bought a 97 lesabre for my kids to drive a few months ago. This was a mint condition grandma driven car with the venerable 3.8lv6.. The kids just about craoked when I picked it out as it is not the most stylish thing in the world. It soon earned the nickname of the "the couch" which was shortened from "the rolling couch".

Anyhow it only has one problem that I can find. When the AC is on and you stomp on the gas, the fan output cycles to the defrost ports and then as you get up to speed, it cycles back to the dash vents.

Any clue as to what might cause this?? I believe this to be some vacuum problem, but looking for a more expert opinion..

Ever considered not "stomping on the gas?" In a car that old, that's likely to turn it inside out.

 

[CobiaXL]

Re: 1997 Buick Lesabre problem

your vacume line to the selector is probably off or has a hole in it.

 

[GA_Boater]

Re: 1997 Buick Lesabre problem

your vacume line to the selector is probably off or has a hole in it.

Possible, but unlikely. If that was the case the heat/ac controls wouldn't work at all. The OP described a classic under hood vacuum problem. Vacuum lines become brittle with age/heat and crack. The propane trick works!.

 

[BlkY2k]

Re: 1997 Buick Lesabre problem

3.8 s were famous for vac leaks on their plastic intakes, they have since fixed the issue. The above method works very well for finding cracked hoses or you can spend all day tracing hoses. If it is a intake a quick way to tell is start the car and try to remove the oil filler cap from the valve cover. Mine was so bad you couldnt hardly pull it off with both hands and when you did it would stumble and die. I`m not saying that is your problem but it is a quick check. G/L and let us know.

 

[sw33ttooth]

Re: 1997 Buick Lesabre problem

my f 150 has the same issue if the air is on max ac. if i turn it to normal ac no issue. its also so cold that i only use max ac if its 90+ degrees out.

 

[robert graham]

Re: 1997 Buick Lesabre problem

My wife's 3.8V6 regal had a similar A/C problem, the dealership found the leaking vacuum line very quickly and fixed it for a few dollars. The dealership guys probably know exactly where to look! Good Luck!

 

[stackz]

Re: 1997 Buick Lesabre problem

either that craptastic plastic intake manifold is leaking or the line leading to the a/c vacuum tree (behind the controls in the dash) is leaking.

if its the line, you just replace it and be done. if its the intake, try to find another one and while you're waiting go to the parts store and grab a one-way check valve for the main feed to the tree and splice it in so when the engine loses vacuum under load, the a/c system will still retain its vacuum.

 

[ajgraz]

Re: 1997 Buick Lesabre problem

Or it could be bad rubber nipples inside the vacuum-operated AC controller module under/behind the glovebox. I have a 1998 rolling couch, they all develop this same problem eventually (in 2000+ H-Body switched to electrical AC control modules, which have their own consistent problems).