Consult the PA Experts

[Smitty's Buick]

OK, so the problem I have isn't on the PA, but on the 99 Olds Intrigue. Hoping that the problem could be related to a similar system in the PA.

The thread is here:
http://www.automotiveforums.com/vbul....php?t=1055040

The climate control fan output gradually decreases when the car is run at cruising speed for about an hour. I've described it in detail in the thread. There has been almost 40 views of the thread, but no comments. I'm hoping maybe you guys might have some ideas. The guys in the Intrigue forum are great and very knowledgeable, so I'm kind of scared that nobody has posted.

Any thoughts or comments are welcomed!
Smitty's Buick

[TopherS]

If I remember correctly, the HVAC unit in the dash controls the blend doors. And I've also read that the blend doors in many cars are controlled by electric motors, not vacuum. It may be that your HVAC unit is faulty. You might check at a salvage yard for a used replacement unit, as the dealer will charge a lot for a new one.

[Jrs3800]

Originally Posted by Smitty's Buick

OK, so the problem I have isn't on the PA, but on the 99 Olds Intrigue. Hoping that the problem could be related to a similar system in the PA.

The thread is here:
http://www.automotiveforums.com/vbul....php?t=1055040

The climate control fan output gradually decreases when the car is run at cruising speed for about an hour. I've described it in detail in the thread. There has been almost 40 views of the thread, but no comments. I'm hoping maybe you guys might have some ideas. The guys in the Intrigue forum are great and very knowledgeable, so I'm kind of scared that nobody has posted.

Any thoughts or comments are welcomed!
Smitty's Buick

Is this a 3.5 Twin Cam or a 3800?

I do think you have a vac leak or the vac line is getting sucked flat.. You will need to check the vac lines to make sure they have not degraded, as well you may want to try to locate the vac canister and the lines to it... From what I can gather Mode is Vac actuated on this car, and the Temp is electric..

[Smitty's Buick]

Jrs3800 -
This is a 3800 car. I have thought that it was probably vacuum, but wanted to consult the forums first to see. Does the engine make a difference?
Smitty's Buick (& Oldsmobile)

[Jrs3800]

a little difference but not by much...

Look at the rear of the intake, should be a large line to the brake booster, there should be a smaller line and if memory serves this line will be the vac line for the Mode control..

[Smitty's Buick]

It's taken me a while to get back to this problem, but I was finally able to do so yesterday. I found the vacuum line and inspected it all the way into the plastic corrugated tubing. I saw no obvious problems (cracks, kinks, breaks, etc.). I pulled the end off of the back of the intake and pulled a vacuum on it using my lungs.

The line seemed to hold a vacuum OK, but it seemed to take quite a "few cycles" to get what felt like a good vacuum. Is this "normal"? Given that problem gets worse as time goes by (heat?) the vacuum may be worse.

I guess I'm looking for any other ideas to try. Any suggestions? Thanks!

Smitty's Buick