How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask rpmdiag Your Own Question
rpmdiag, Tech and Instructor
Category: Acura
Satisfied Customers: 7892
Experience:  Since 1975
Type Your Acura Question Here...
rpmdiag is online now
A new question is answered every 9 seconds

Irregular heating on a 2005 MDX, Sometimes the air just

Customer Question

JA: Hi. What is your issue regarding?
Customer: irregular heating on a 2005 MDX
JA: Sometimes things that you think will be really complicated end up being easy to fix with a Acura. The Acura Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so he can help you best.
Customer: Sometimes the air just blows cold.
JA: Are you hoping to fix this yourself?
Customer: If possible...
JA: Is there anything else the Acura Mechanic should be aware of about your Acura?
Customer: Check the coolant levels
JA: OK. Got it. I'm sending you to a secure page on JustAnswer where you can place your fully refundable $5 deposit (plus $13 after the Acura Mechanic responds). While you're filling out that form, I'll tell the Acura Mechanic about your situation and connect you two.
Submitted: 1 year ago.
Category: Acura
Expert:  rpmdiag replied 1 year ago.

Hi, I’m Ron and I can help you.
I have been in this business since 1975 and also teach automotive repair. I am confident
we can resolve your problem together. Please understand that I don't know your skill
level. I can't see, smell, hear, or touch the vehicle either, so it may take a few replies to
get to satisfactory results. Please be patient!
I also try to give all of the information you may need, expecting a “positive rating” in
return. I will also continue assisting you after you have rated me, if necessary. If there
is any reason I cannot get a positive rating, please let me know why “in advance”, so I
can go another direction for you. I am sorry you’re having this problem; I’ll help you
through it.

When this happens, it's usually caused by a sticking T stat or a blockage or air in the cooling system.

Thanks, Ron

Customer: replied 1 year ago.
Hi Ron,To give you more detail...I have checked the engine coolant level, both the radiator and the resevoir are filled (in fact the resevoir's level is above "Max", but I am not sure when it had it's last flush as we purchased the car about six months ago.As for the AC controls - both physical buttons close to the top of the dashboard and the virtual interface on the touchscreen seem to be responding in the expected manner - except that the heat is inconsistent. Yesterday, it blew nothing but cold air no matter the setting. Earlier today after inspecting the fluid level in the radiator and the resevoir, it blew warm/hot air... so not exactly working in a depenable manner.As for ability - I have worked on cars a little - changed wheel bearings, brake pads, suspension and serpentine belts but in terms of AC I have only recharged the cooling system (which didn't seem to actually help that much).I hope this information is of some use to you.
Expert:  rpmdiag replied 1 year ago.

Okay, the answer I originally gave you is still valid and can cause this problem as well as sticking blend doors, now that I know a bit more. Thanks for the info, and please don't forget to rate me and keep this link in case you need me again later on.


Customer: replied 1 year ago.
Okay - but how do I fix the problem?
Expert:  rpmdiag replied 1 year ago.

First identify what the problem is, then we do the repairs as needed.

Thanks again, and please don't forget to rate me and keep this link in case you need me again later on.


Customer: replied 1 year ago.
how do I determine what is the cause of the problem?
Expert:  rpmdiag replied 1 year ago.

Your original complaint was intermittent heat, so that's what I'm dealing with. Check the T stat and flush the cooling system if it's still not working right, have the cooling system flushed. Step by step.

Thanks again, Ron

Customer: replied 1 year ago.
Hi Ron,Yes, that is the complaint which I am trying to resolve.The agent who connect me to you asked me if I was looking to fix the problem myself and I replied "yes". So, I was looking to get advice on determining the exact problem, whether it is something I can fix myself and if so what is necessary to fix it.For example I would appreciate it if you could provide me with a little information regarding how to determine if it is in fact the T Stat that is the problem - what am I looking for (loose connections? melted parts?), where (is it easy to see or do I need to lift the car?) and how (do I need remove it? Does it requires specialized tool?)Thanks in advance for your understanding.
Expert:  rpmdiag replied 1 year ago.

Yes there are special tools to remove the stat to check it. You may as well replace it seeing that you're already there. The flushing for debris in the system is done with a pressure machine. This mist likely is not something you can do at home.

Thank you.


Customer: replied 1 year ago.
I see, thank you for the additional information. I will move onto those checking those once I check if the control valve is functioning properly.
Expert:  rpmdiag replied 1 year ago.

You're welcome, thank you too and please don't forget to rate me.


Customer: replied 1 year ago.
Hi Ron,I was just checking the HVAC control valve (some others have mentioned this malfunctioning being a common cause of problems). I've changed various AC settings but have not noticed much (or any) change in the valve arm's position.I've read that there should be around 90 degrees of motion, but this on has not really budged from perpendicular to attached hoses and there is quite a bit of resistance if I try to move it using my finger.Could you tell me if this sounds problematic or let me know exactly adjusting which AC control should translate to a corresponding movement in the valve's lever?Thank you in advance.
Expert:  rpmdiag replied 1 year ago.

Possibly, but we need to start doing a bit more diagnostics and less reading. We'll ever find the true problem until we start doing some work/diagnostics.

Thanks again.