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Doug
Doug, ASE Certified Technician
Category: Mitsubishi
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Experience:  Mitsubishi employed and Factory trained ASE certified technician
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Mitsubishi Galant ES: 2002 Galant has had a clicking noise

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2002 Galant has had a clicking noise behind the heat control knob. Sometimes the control knob works and sometimes it doesn't. Now it has stopped clicking and the temp won't switch over from cooling to heat. The dealer wants to charge me $1000 to replace the heating core. I think that isn't the issue. Look slike a lot of people have had a similar problem.

Hi,

You are right in that heater core by itself certainly isn't going to make a clicking noise.

Can you provide your VIN so that I can verify if you have a particular component in your heater system that is known for this issue? The component in question, when it develops the clicking noise, will result in a lack of heat at times and certainly sounds like this may be the case here.

Thanks

Customer: replied 4 years ago.

VIN: 4A3AA46G12E078156

Thanks.

This vehicle does have the system I had in mind.

In your Galant the heater system has a shut off valve that is used to restrict coolant flow into the core. The purpose of this is to maximize AC cooling efficiency when the heat is not in use, but not allowing any coolant to enter the core, thereby lowering the temperature of the air handler and therefor making the AC evaporator not have to work as hard.

The valve for the heater core is mounted right on the core and is mechanical in nature. The valve is operated via an electric motor, and this is where your clicking comes in. When the motor strips out internally, it will result in clicking when the motor tries to open/close the valve, as in when you are adjusting the temperature. If the bad spot of the gear is in the right position, it will prevent the valve from opening at all, resulting in no heat.

There are two areas of concern here. First and foremost is of course the stripped out motor, but additionally consideration must be taken for the condition of the valve. While these motors do strip out from age and normal wear, if the valve were to stick/seize in position it would cause the motor to strip out as well.

From here you will want to just confirm the clicking is coming from the valve control motor by placing your hand on the motor while running the dial to try to make it click, feeling for the click. The motor is located on the passenger side of the air handler, accessed from either behind the glove box or by removing the radio and reaching through it's opening. Once confirmed you will want to remove the motor and normally confirm the valve is not seized.... if you have had the heat come and go a few times, you can skip this though since it is obviously moving then.

Replace the heater valve control motor and you should be all set.... and for a lot less than $1000!
The motor costs about $140 the last time I replaced one, and count on an hour and change to replace the part (it can be done in about 20 minutes, but if the person doing it has not done one before it can take a while to get acclimated to the tight access.


If you have any questions or need further assistance please just let me know and I would be happy to continue with you.
IF you feel the need to use one of the lower two negative ratings, please contact me first via the Reply/Continue Conversation link so that I may address your concerns.
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Customer: replied 4 years ago.

One more question - so I think I'm understanding that it's the heater valve control motor that needs replacing, not the heater core? Is this correct?

Absolutely.... let me see if I can find an illustration to help show what I was describing.
Allow me a few minutes to do some digging.
Customer: replied 4 years ago.

OK, thank you!

Thanks for your patience... I'm not finding ideal pictures, but I have a few to help get an idea.

Looking at the side of the HVAC box (pretending it were out of the car), here is a picture of the motor and how it engages the valve:

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Note that in this picture, the water valve motor is number 2 (see the similar arm as in the first picture?), number 1 is the compressor controller and is only shown so that you can see the proximity.


I hope this helps, let me know if you have any other questions.
Customer: replied 4 years ago.

What I'm going to do is share all this info with my son and then determine where to go next for mechanical help. I am not feeling like the service department at the dealership paid close enough attention to my explanation about the clicking. They just replaced the thermostat and charge me for it with no results. Then they went to the heater core as the next step claiming it is blocked, but if I am understanding your explanation correctly replacing the heater core would not solve the issue. The problem lies in the heater valve control motor, correct?

Sounds like a plan.
It is terrible to think that the dealership was unaware of this issue, however it is a system that was only used for a few years.
Never the less, no reason I can see why they could logically come to the conclusion that you need a heater core though.... all they do is clog or leak. If it leaked you'd know, and if it was clogged it wouldn't come and go.

Correct with the heater valve control motor. Also sometimes referred to as the Water Shut Off Motor.
The motor strips internally and the drive gear spins trying to move the lever you see in the picture, but the load from the valve is too much and it causes the gear to jump teeth, which is the clicking you hear. If it catches just right at a good section of teeth it can move the valve properly, then go back to not working the next time, etc.

I don't see any likelihood of you having anything more than this as an issue.... meaning if the valve were jammed causing the motor to strip it wouldn't come and go ever. Again you can locate the motor and put your hands on it to feel the click when it occurs if you want to verify it 100% yourself prior to having any work done.