Fan kicks on when I start my Explorer from a cold start

[muskogeezeke]

Hey guys, obligatory newbie announcement.

EDIT: Sorry, guess you would like more info: 02 Explorer, 4.0, V6, 2WD

Used this form before many times. You guys rock, finally decided to register cause I got a problem I just cant figure out.

Car overheated and cracked the thermostat housing, causing alot of smoke.

Dealer said it was due to the coolant needed to be replaced, wanted $1100 to fix it.

Got it towed to my house. I replaced the thermostat housing, thermostat, gaskets and coolant temp sensor.

Started car, no leaks. However, even from a cold start, the fan kicks on automatically. I am not sure if it is cycling coolant. I got it to normal operating temperature, doesn't seem to get too hot once I get it to running temp, but has a slight burning smell when I turn the car off.

What do you think? My only guess is the pigtail that connects to the coolant temp sensor.

 

[Kesp4.0]

Are you talking about your radiator fan?

 

[muskogeezeke]

Are you talking about your radiator fan?

Yes, I believe so. The fan at the front of the vehicle.

 

[Kesp4.0]

The fan in a 3rd Gen Explorer isn't an electric fan. It is powered by the water pump so it will always be running.

 

[Exproblems]

.

Car overheated and cracked the thermostat housing, causing alot of smoke.

Dealer said it was due to the coolant needed to be replaced, wanted $1100 to fix it.

Got it towed to my house. I replaced the thermostat housing, thermostat, gaskets and coolant temp sensor.

Started car, no leaks. However, even from a cold start, the fan kicks on automatically. I am not sure if it is cycling coolant. I got it to normal operating temperature, doesn't seem to get too hot once I get it to running temp, but has a slight burning smell when I turn the car off.

What do you think? My only guess is the pigtail that connects to the coolant temp sensor.

The Ford 4.0L t-stat housings can crack even with fresh or newer coolant running through them and have never over heated prior to that, mine did. They crack from age and use through expansion from heating up and cooling down over the years. The dealership guy who quoted you $1100 to replace a t-stat housing, temp sensor and coolant was smoking "crack" that day he quoted you that price. Even at dealership prices, it shouldn't have cost more than $300-400 or so parts & labor, unless they were some other things wrong not mentioned.
Hopefully you didn't blow a head gasket when it over heated. You could have damaged a cylinder head, but the dealership should have seen that when they looked at it. Check your coolant and engine oil for signs of contamination, cross mixing of oil in the coolant or coolant in your oil. Maybe what you are smelling is old coolant still burning off of the engine. Check to make sure you are getting good heat through your heater core into the cabin, to see if you have the cooling system "burped" of any air pockets left in the system when you re-filled it with new coolant.
"Kesp4.0" is correct, the engine cooling fan in 3rd gen Explorers is not an electric fan, but a mechanical "clutch" operated fan and it spins right after start up. The fan will spin at a faster pace as the cooling demand (heat) goes up and the clutch expands and engages the fan more. When the cooling demand goes down, the fan spins at a slower pace.

 

[muskogeezeke]

The Ford 4.0L t-stat housings can crack even with fresh or newer coolant running through them and have never over heated prior to that, mine did. They crack from age and use through expansion from heating up and cooling down over the years. The dealership guy who quoted you $1100 to replace a t-stat housing, temp sensor and coolant was smoking "crack" that day he quoted you that price. Even at dealership prices, it shouldn't have cost more than $300-400 or so parts & labor, unless they were some other things wrong not mentioned.
Hopefully you didn't blow a head gasket when it over heated. You could have damaged a cylinder head, but the dealership should have seen that when they looked at it. Check your coolant and engine oil for signs of contamination, cross mixing of oil in the coolant or coolant in your oil. Maybe what you are smelling is old coolant still burning off of the engine. Check to make sure you are getting good heat through your heater core into the cabin, to see if you have the cooling system "burped" of any air pockets left in the system when you re-filled it with new coolant.
"Kesp4.0" is correct, the engine cooling fan in 3rd gen Explorers is not an electric fan, but a mechanical "clutch" operated fan and it spins right after start up. The fan will spin at a faster pace as the cooling demand (heat) goes up and the clutch expands and engages the fan more. When the cooling demand goes down, the fan spins at a slower pace.

Yea, I am was pretty shocked myself by the price.

Thanks, I didn't know the fan always runs. I get good heat from heater (checked last night).

I will check for cross contamination. Many thanks!

 

[Bobmbx]

I think you've fixed your problem just fine. The smell will be there for a while. Just keep an eye on your coolant level (check when cold!!) for a week or two.

Otherwise, good job.