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Neal
Neal, Mechanic
Category: Car
Satisfied Customers: 8349
Experience:  Auto repair pro and Mechanic on multiple makes.
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My Mazda MPV 03 cooling fan runs most of the time and make

Customer Question

My Mazda MPV 03 cooling fan runs most of the time and make loud noise. The car does not heat
Submitted: 7 years ago.
Category: Car
Expert:  Neal replied 7 years ago.

The fan will also run when the A/C comprssor is running, along with running to keep the engine cool.

 

If it is running more than normal there may be a problem with the cooling system and the fan has to run more to keep the temp in the normal range.

 

If the fan is louder than normal the fan itself may be going bad.

 

 

 

 

Customer: replied 7 years ago.
The fan is running more than normal. What cooling problem could be like
Expert:  Neal replied 7 years ago.
It could be many things including a plugged up radiator or a leak in the system. The first thing to do is to check for any leaks and to pressure test the sytem and the radiator cap. Most shops will do this for a small charge or even for free. You can also check the radiator by checking the temperature difference between the top and bottom of the radiator. If the radiator is hot at the top and cold at the bottom, it is plugged up and needs to be replaced.
Customer: replied 7 years ago.
How can I check for any leaks and pressure test?
Expert:  Neal replied 7 years ago.
You can visually check for leaks, but you will need a pressure tester to pressurize the system. Some parts stores will loan you the pressure tester for free if you leave a deposit.
Customer: replied 7 years ago.
can the problem be associated with thermostat failure?
Expert:  Neal replied 7 years ago.
It is possible but not very common.
Customer: replied 7 years ago.
One final question, how do distinguish the problem caused by thermostat failure or radiator problem
Expert:  Neal replied 7 years ago.

By checking the radiator as I described you can rule out the radiator.

 

When the engine is at normal operating temperature, shut the engine off and see it the radiator is cold at the bottom. The higher you have to move up the radiator to find heat the worse it is. Be carful of the fan, it can kick on even when the engine is off. If you have one of those non-contact thermometers, they work well to check it.

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Customer: replied 7 years ago.
Can you explain more "When the engine is at normal operating temperature, shut the engine off and see it the radiator is cold at the bottom. The higher you have to move up the radiator to find heat the worse it is"
Expert:  Neal replied 7 years ago.
If the radiator is cold at the bottom and hot at the top it means the radiator is plugged up. It always gets plugged up from the bottom to the top.
Customer: replied 7 years ago.
what if the bottom is also hot? What other problem could be
Expert:  Neal replied 7 years ago.
There are many possibilities, I have given you the most common. Please rule those out and then we can go on from there if need be.
Customer: replied 7 years ago.

Hi Neal

I took my MPV to a mechanic who checked radiator pressure and it was OK. Then he flushed the radiator and put new coolant. The problem is the same.

 

I compared my mpv with a friend's mpv and I noticed my right fan stops for a second and then runs slowly whereas my friends mpv the right fan comes to complete stop for few seconds and then works. I also noticed my fan is more noisy compared to his car.

 

Does that give you any clue?