2016 cx-5 heating question

[dniksich]

First post so hey everyone! I'm working on a friends 2016 CX-5 that he said had a few problems that I pretty much figured out except he said it overheated on him once while getting his oil changed and the guy topped off the coolant. I got it towed here because the starter went out but I got that changed and it's good now. I drove it with my scanner on it and it never got over 190 degrees so I assumed it was a fluke of some type maybe. I was getting ready to tell him it was done but happened to check the heater and it's blowing cold. Both heater hoses are cold also so I'm guessing the blend door is ok. Figured I'd check codes and got a P011A? My scanner says recommended fixes are temp sensor or thermostat. My guess is the code is from the flow problem. What would be your suggestions be for the first thing to look at? Do these cars have a coolant control valve inline with the heater core hoses? Thanks for any help.

 

[dniksich]

Been doing a lot of researching and I think it might be a clogged core. Gonna try to back flush it in the morning and see if that is the issue.

 

[Mazdiod2]

There is an issue here.
You might need to change the core, there are Youtubes on how to do this without removing the entire unit, but you have to procure the small heat exchanger that fits in the unit.
Backflushing might not work because corrosion has built up inside the pipes.

 

[dniksich]

There is an issue here.
You might need to change the core, there are Youtubes on how to do this without removing the entire unit, but you have to procure the small heat exchanger that fits in the unit.
Backflushing might not work because corrosion has built up inside the pipes.

I did see the video on using the factory metal lines and re-crimping on the new one and that sure is the way I'm gonna go if needed but what do you mean by the small heat exchanger? Thanks

 

[dniksich]

Not the core. Pulled the lines and ran water through it with no problem. What's next to try?

 

[N7turbo]

I was getting ready to tell him it was done but happened to check the heater and it's blowing cold. Both heater hoses are cold also

Do these cars have a coolant control valve

Do the radiator and coolant get hot? What does a scan tool say about the coolant temp?

 

[dniksich]

Definitely a flow problem. Just put it back together and let it run for a few minutes and temp sensor 1 was 164 degrees while 2 was 67. Top rad hose was getting hot but bottom was cold. Maybe thermostat is stuck closed?

 

[N7turbo]

There was a TSB for the coolant control valve, however my understanding is it defaults open, not closed, when it fails.

It also doesn't list 2016 as an applicable year.

Maybe you just need a thermostat.

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[dniksich]

Thanks, gonna try a stat next.