Climate Control Issues?

2016 CHEVROLET EXPRESS
344,298 MILES • 4.8L • V8 • 2WD • AUTOMATIC
Avatar
KGETZ
  • MEMBER
  • 104 POSTS
My workplace issued me a van for deliveries. I am running into an issue when I have to accelerate to go up a hill, the climate control diminishes. Once I let off the accelerator, then the fan comes back at set speed. Are you guys familiar with this on the Express 2500s?
Apr 19, 2025 at 6:02 PM
Advertisement
Avatar
STRAILER
  • ✓ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Yep, this happens when the vacuum check valve goes bad for the HVAC system which is under the hood in the vacuum line from the engine to the HVAC system. Or if there's a leak or missing vacuum reservoir, the system can’t hold vacuum. I would lift the hood and use a flashlight to inspect the vacuum lines from the engine to the firewall. Please upload pictures or videos in your response of any problems so we can see what to help you with.

Apr 20, 2025 at 12:19 PM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.