Hi all, juat picked uo my 1st s2k and i have a no heat issue, looking for guidance, just purchased my first s2k on Saturday. AC blows cold and doesn't overheat, but no heat from cabin. Ran the DTC test below and got 1 solid blink indicating air mix motor. I diagnosed the rod connected to the control valve and noticed the following: •If dial is turned to cold, the rod connected to the control valve couldn't manually be pulled open•If dial is set to hot, the rod can be manually pulled open•While open, when changing from hot to cold, rod actuates and pulls inward (but doesn't go outward when changing dial back to heat)•Blower motor blows more air when cold vs hot Any idea what this can mean? Is this a faulty air mix motor? Control valve? How can I diagnose? Thanks all!

 

Is it possible that the coolant line needs bleeding? Was the coolant changed or the radiator recently?

Thanks!

 

Well I test drove it and let it stay on for quite a while when I purchased it, drove home over 3 hours and have never once seen radiator temp increase. Fans work as normal and a/c blows cold - so I can't assume it would need bleeding without having it overheat?

I could be wrong, but I come from german cars mainly lol.

 

With these cars, one sign of no interior heat is that the coolant needs to be bled. Air trapped in the system prevents warm air from reaching the interior.

I did not realize you stated multiple threads on the same topic. To mods, it's fine if you want to delete my posts here.

 

Gotcha okay I'll try to bleed anything else out. Would the rod not moving cold to hot, would that also be a potential blend-door issue with the motor, alongside potentially trapped air?

I apologize i didn't mean to this is my first time on this forum - i can't see where to edit or delete threads.

 

If you pull on the mix valve in the engine bay, does hot air blow? I have the same issue and haven’t gotten around to replacing the mix valve in the engine bay yet. I just have to set the temp knob in the cabin, then pop the hood and pull the rod to match.

for context, if I turn cold to hot, I have to get out. For hot to cold, i do NOT have to go under the hood to get the air temp to change

annoying, but i drive the car so infrequently the work has never made it high up my to do list

 

It does not. I pulled it manually and no hot air (in fact it almost even seemed colder LOL). The only notifiable thing that's different is the blower mower produces more air when it's cold vs hot and I wasn't sure if that's normal either.

I'm thinking it's 1 of these 2 things after some research. Either the control valve internal part is faulty and stuck (open or closed), not sure which affects which yet. And/or, the system isn't properly bled. Theoretically if I pull the rod and have it set to heat, if bled the system and the internal valve is working it should produce heat. So even without the motor (which seems to be an issue unless tension on the adjuster arm is too tight), I probably have more than one issue lol!

 

No problem with the double post. Sometimes, I get a reprimand from the Mods when I do this.

method to bleed the coolant line. I had to let the car idle to operating temp and run for nearly 20 minutes to get rid of all the trapped air. Heater at the full hot setting. Once fully bled, I got hot air almost immediately (like I can feel heat in 30 seconds, even when the car has sat overnight). Having the front end of the car raised can help bleed the air (like parking on a slope, or jacking the front up).

Coolant bleed link.

 

You absolutely need to rule out air in coolant FIRST. Also, do not drive it any further until this first thing is complete.

Its quite common that with these cars, when there is air in coolant, it'll drove fine, no overheating, no temp gauge creep. Only symptom will be no or even low heat.

Then one day outta the blue, withno warning, while just driving normally, engine will overheat and destroy itself.

If you're really, really lucky, you just blow head gasket. More likely you'll do irreversible damage. New engine.

So take this seriously. This is why everyone is going here first, even though you've given clear indication it might just be under dash, heat door issues. You gotta rule air in coolant out first.

These cars are notoriously difficult to bleed air from coolant.

Whenever coolant changed, strict bleeding regiment has to be followed. Key is, if heater isn't hot enough to burn your fingers, you still have air. Still have overheating risk.

The Lisle funnel method works great. Along w nose uphill, and cracking open front bleeder screw till it spouts.

Once you do that, if still no heat, THEN we can talk about rods and doors.

Also, look for sticky thread, things for new owners to do and inspect. Comprehensive, curated list by S2K experts and forum knowledge.

 

Awesome thank you so much for this!! I will do this tomorrow and let.you all know results.