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Steve
Steve, Service Manager
Category: Ford
Satisfied Customers: 5494
Experience:  25+ years experience as a professional technician ; ASE L1 master Technician
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1994 Ford Aerostar: overheating..thermostat, the radiator cap..flushed

Customer Question

i've got a 1994 Ford Aerostar 3.0 L that keeps overheating. I've changed the thermostat, the radiator cap. I flushed the radiator twice. I have heat. the fan blows. there is no leak. What is my problem? PLEASE!!
Submitted: 7 years ago.
Category: Ford
Expert:  Tim West replied 7 years ago.
Thanks for visiting JA.com
Does the vehicle overheat when you are driving or does the vehicle overheat at idle?
Customer: replied 7 years ago.
both, but not as bad on the highway. at 35 mph it gets real hot just like idling
Expert:  Tim West replied 7 years ago.
Okay, thanks. First thing are the fans working properly? When the a/c is on the fans should be on. When the vehicle reaches 220degrees they should turn on also.
If the fans aren't working properly we might have a problem with coolant temp sensor or radiator fan. Let me know.
Customer: replied 7 years ago.
The radiator fan definitely works, and it doesn't overheat without the thermostat, but it obviously doesn't get hot enough for heat
Expert:  Tim West replied 7 years ago.
Since you flushed the system already I doubt there is a chance for an obstruction in the cooling system. However, the radiator is known to clog. If you have an infared thermometer check the temperature of the radiator. Look for a hot spot, a spot in the radiator much higher than others. If there is a hot spot, it's probably an obstruction and the radiator should be replaced. If the radiator is good, it's probably a bad water pump.
Did you bleed the cooling system properly?
Customer: replied 7 years ago.
what other options are there that are more cost effective?
Expert:  Tim West replied 7 years ago.
I will release the question to the other experts maybe one of the other guys has a more cost effective solution.
Customer: replied 7 years ago.
yeah, the water is definitely being pumped, i can see it when the cap is off
Expert:  Steve replied 7 years ago.

Hello;

From the description you ahve there I think the previous expert was on the right track; you most likely ahve deposits in the radiator restricting coolant flow through part of the core.

The fact that you ahve heat indicates that trapped air in the system is not likely to be the cause of the problem.

If you can see coolant circulating through the top of the radiator then the thermostat is opening and the water pump is circulating the coolant.

You have stated that the cooling fans are operating to move air through the radiator core, so it's not a fan issue.

The only thing left that could account for the overheating problem is poor radiator efficiency.

If antifreeze is not changed every 2 years like the manufacturer specifies, it will start to break down; evidence of this would be any traces of white mineral deposits inside the radiator. These mineral deposits form inside the radiator core tubes, restricting coolant folow through the tubes. The radiator may still be able to flow enough coolant through the core that you can see it moving if you look down insode, but if the flow is significantly reduced through part of the core it dramatically reduces the ability of the radiator to transfer heat to the surrounding air so the engine will overheat after running for a while.

These types of mineral deposits cannot be removed by flushing the radiator; they are as hard as rock and are not dissolved by any type of flushing solvents on the market. If the core is restricted the radiator must be replaced with a new one.

Steve, Service Manager
Category: Ford
Satisfied Customers: 5494
Experience: 25+ years experience as a professional technician ; ASE L1 master Technician
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