no heat
11-02-2017, 08:12 PM
#1
Junior Member
Thread Starter
Join Date: May 2015
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
no heat
does anyone know how the vacuum should change at the bypass valve while changing the temperature slider inside the car?
i have no heat in the car, the slider sounds like its moving the door in the hvac system. i do have vacuum pressure to open the flaps to change air direction in the vents.
the car sat for a long time and needed some tlc. so far, i've replaced a few hoses, the bypass valve, radiator, cap, t-stat and heater core.
i have no heat in the car, the slider sounds like its moving the door in the hvac system. i do have vacuum pressure to open the flaps to change air direction in the vents.
the car sat for a long time and needed some tlc. so far, i've replaced a few hoses, the bypass valve, radiator, cap, t-stat and heater core.
11-02-2017, 10:03 PM
#2
Supreme Member
Re: no heat
Have you tried putting vacuum to the bypass valve directly?
11-04-2017, 10:31 AM
#3
Junior Member
Thread Starter
Join Date: May 2015
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
Re: no heat
i found by removing the vacuum line from the bypass valve i get heat in the car.
maybe there is a leak in the switch that is sending vacuum when it shouldn't....that is my next place to look.
maybe there is a leak in the switch that is sending vacuum when it shouldn't....that is my next place to look.
11-04-2017, 11:44 AM
#4
Junior Member
Join Date: Nov 2017
Location: Gem State
Posts: 21
Received 0 Likes
on
0 Posts
Engine: LG4
Transmission: 700R4/4L60
Axle/Gears: 2.73
Re: no heat
Still looking for how to introduce myself on this forum. Not an F-body guy, but saw useful info from some great people!
The valves by default allow coolant flow, i.e. heat, without vacuum. GM typically only supplied vacuum to heater valves when the control head was set to 'MAX' for A/C, or the temp lever was slid all the way to cold. Fully automatic climate control was another story.
I've lost count of the number of GM heater valves I have replaced (multiple styles) because they stick open, closed or leak.
Jerry
The valves by default allow coolant flow, i.e. heat, without vacuum. GM typically only supplied vacuum to heater valves when the control head was set to 'MAX' for A/C, or the temp lever was slid all the way to cold. Fully automatic climate control was another story.
I've lost count of the number of GM heater valves I have replaced (multiple styles) because they stick open, closed or leak.
Jerry