HVAC AC drops to heater vent on acceleration

Tiny
KRR711@GMAIL.COM
  • MEMBER
  • 1998 CHEVROLET LUMINA
  • 3.1L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 178,000 MILES
I have heard variations of this question. Upon acceleration, the cold AC drops to heater vents. After stabilizing speed, the AC will go back to the upper vents. Please help. This is my only car and I have chased all the vacuum lines and all looks clean and unbroken. If I could afford the cost of repair, but I cannot find anyone here in Indianapolis to work on it. Thank you. Kenny
Do you
have the same problem?
Yes
No
Monday, October 1st, 2018 AT 12:33 PM

5 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good afternoon.

When you were looking at the lines, did you find a big tank?

That is the tank that fails. It is supposed to store vacuum for the doors under power.

Re check the lines again.
Was this
answer
helpful?
Yes
No
Monday, October 1st, 2018 AT 12:54 PM
Tiny
KRR711@GMAIL.COM
  • MEMBER
I will check in the morning and let you know!
Was this
answer
helpful?
Yes
No
Monday, October 1st, 2018 AT 1:04 PM
Tiny
ASEMASTER6371
  • EXPERT
Sounds like a plan.

Roy
Was this
answer
helpful?
Yes
No
+1
Monday, October 1st, 2018 AT 1:05 PM
Tiny
KRR711@GMAIL.COM
  • MEMBER
Hello Roy, sorry about the delay but I just got the car fixed. It was the vacuum reservoir on the 1998 Lumina. What happened was the mounting screw for the tank had rusted away and the tank was flopping around and pulled the hose off. By the time I actually located the tank (buried really deep under the driver's side fender well) I bought a new tank and replaced the screw and nut. Now it runs perfectly! AC does not kick out on acceleration. Thank you for sharing your skill!
Was this
answer
helpful?
Yes
No
Wednesday, October 3rd, 2018 AT 1:49 PM
Tiny
ASEMASTER6371
  • EXPERT
You are welcome.

Always glad to help.

Roy
Was this
answer
helpful?
Yes
No
Wednesday, October 3rd, 2018 AT 1:50 PM

Please login or register to post a reply.

Recommended Guides