HVAC Issues

I am still looking through tons of old threads, but figured I'd post this up as it seems to be more than 1 issue in relations to the HVAC unit.

 

I have auto dual climate control.

 

I get the notorious heat on the driver's side, but ice cold on the passenger side when the heater is set at 85 on both sides. However, mine is slightly different than most. I only have this issue when my revs are under ~2.5k rpms (Coasting, idle, or just driving fuel efficient). If I am at or over 3k rpms, I get blazing hot heat from both sides. If I am idling then my driver's side goes cold too.

This is issue #1.

I plan on getting a coolant flush on Monday when the shops open back up. Any other suggestions would be gladly accepted.

From everything I've found, the only thing that needs to be done, is the heater core needs to be flushed and reverse flushed. I'll take it to the Dealership to get this done and report back.

*UPDATE!* I went in and had the coolant flushed and that fixed the issue! I now have heat on all sides! A bit too much I might add!

 

Now issue #2.

It doesn't matter what mode my HVAC is in, I only get air from the main vents. I don't get anything to my feet or to the defrost. I am thinking it is a jammed door in the system? I just wanted suggestions before I go tearing apart my dash.

**This one is still under investigation.

 

I will keep searching through old posts. Any information I find, I'll post here for future reference.

The mechanic that just replaced my headgaskets said the same thing about my heat. That the cold air door is stuck open somewhere and they'd have to tear down the dash in order to find and replace the issue.

 

Let us know what else you find, as I've been searching as well. Not paying $600 for a plastic door to be replaced...

Mine just started blowing cold from the passenger side this AM.

 

What exactly is the coolant flush?

 

My motor is only 8 months old, radiator only 12 months old.

 

Could it be old gasket material in my heater core? It cannot be old coolant!

the heater cores block this has been covered before.

the passengerside is on the bottom so those tend to block.

 

to identify put full hot on both sides.

 

turn off fan .

 

wait 1 min

 

turn on fan

 

if heat comes out of passenger side for a short time then tapers down its the heatercore.

 

flush is recomended.

Having done this multiple times, I can tell you that flushing by itself will NOT do the trick. THe heating system design is fundamentally flawed because the flow of coolant moves from driver's side to passenger. What I have encountered is that rust from the system blocks flow of hot coolant to passenger side heater core; you have to pull off the hoses, pressure wash/clean the rust out and then you will get hot (or at least warmer) air.

Yup, the best way to clean out the heater core is to disconnect the hoses leading up to the firewall. Some have used some cleaning agents to dissolve out any gunk/rust and flushed, and some have just hooked up a garden hose and let it run for several mins to force out any blockages.

yes i use clr . you can get a circulating pump into warm bucket of soapy water..

flush in both directions. then even compressed air.