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Complete re-edit...

 

I have an '11 Crown Vic (270k miles) with an overheating problem that I believe is being caused by the rad fan not turning. Here's what I've seen so far...

1 - The overheat condition doesn't happen while moving, it only happens while in park after idling for a while

 

2 - Top radiator hose DOES get hot

 

3 - If the a/c is off, the rad fan DOES NOT turn at all during overheating as the temp gauge moves all the way up

 

4 - At normal engine temp the rad fan DOES turn as soon as the a/c is turned on, but I've only observed this so far at normal temperatures.

 

5 - During the times it overheats and the a/c is on, the cabin vent air gets hot and humid right when the overheating occurs. I haven't yet made it a point to check the rad fan at this point to see if it's still turning.

 

6 - During testing, after getting the engine temp up to idle hot and the temp gauge read normal in the middle, to trigger it to overheat I had to run the engine at 2k rpm for over 5 mins before the dash temp gauge began to rise. After the gauge begins to creep up I've let off the gas but the temp continues to go all the way up. Although to trigger the overheat condition I ran it at 2k for a while, it DOES overheat by simply sitting in park and idling.

 

7 - The coolant reservoir cap has a small leak but I don't think this is a major factor. I've continued to top off the reservoir throughout my testing and overall there doesn't seem to be much coolant leaking from the reservoir. Although, you CAN hear air seep from the reservoir cap when you squeeze the top rad hose.

The main problem seems to be the rad fan not turning. Any ideas? I'm all ears.

Edited by bradleyheathhays

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Whats the fan doing? It should be running full speed when hot. Have changed a few fans. Also look for debris between the radiator and ac condenser.

Edited by fordtech1

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If it’s not the fans or the radiator I would suspect the water pump. Does it cool down if you rev the engine?

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Thanks for the replies. I believe the fan is turning ok but I haven't watched out for it specifically yet. I'll check here soon. Actually the radiator did have some crap stuck in the lower part of it which I garden hose sprayed out. I'll check some more between the rad and condenser like you suggest.

 

No, reving the engine does not cool it down.

 

 

After watching it overheat a couple times now a pattern has emerged of coolant leaking from under the reservoir cap while the dash temp gauge still reads normal. After that the gauge goes up to full overheat. What would leaking around the reservoir cap indicate in this situation?

Edited by bradleyheathhays

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When they overheat it pukes out coolant. The cap is supposed to hold 16 psi of pressure to raise the boiling point of the coolant. When it overheats the pressure gets too high and pushes pas the cap and thats why it pukes out the coolant.

When its real hot that fan should be noisy and running wide open. One thing make sure the fan comes on when the ac is running. Fan should always be on when ac compressor is running. If not thats a problem.

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I believe it's the rad fan now. Here's what I'm seeing...

 

1 - The overheat condition doesn't happen while moving, it only happens while in park after idling for a while

2 - Top radiator hose DOES get hot

3 - If the a/c is off, the rad fan doesn't turn at all during overheating as the temp gauge moves all the way up

4 - At normal engine temp the rad fan DOES turn as soon as the a/c is turned on, but I've only observed this so far at normal temperatures.

5 - During the times it overheats and the a/c is on, the cabin vent air gets hot and humid right when the overheating occurs. I haven't yet made it a point to check the rad fan at this point to see if it's still turning.

6 - During testing, after getting the engine temp up to idle hot and the temp gauge read normal in the middle, to trigger it to overheat I had to run the engine at 2k rpm for over 5 mins before the dash temp gauge began to rise. After the gauge begins to creep up I've let off the gas but the temp continues to go all the way up. Although to trigger the overheat condition I ran it at 2k for a while, it DOES overheat by simply sitting in park and idling.

7 - The coolant reservoir cap has a small leak but I don't think this is a major factor. I've continued to top off the reservoir throughout my testing and overall there doesn't seem to be much coolant leaking from the reservoir. Although, you CAN hear air seep from the reservoir cap when you squeeze the top rad hose.

The main problem seems to be the rad fan not turning. Any ideas? I'm all ears.

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Start by replacing the reservoir cap. You know that is bad, you may have hot spots inside the motor boiling the coolant away from them making them very hot and obstructing proper coolant flow. I have had sensors that didn't work because the coolant had been boiled away from them.

 

You have identified a defective reservoir cap and neither you or I know how that will effect the proper operation of the coolant system but it should be replaced first then go about testing the other unknowns.

Edited by gthims

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I believe it's the rad fan now. Here's what I'm seeing...

 

1 - The overheat condition doesn't happen while moving, it only happens while in park after idling for a while

2 - Top radiator hose DOES get hot

3 - If the a/c is off, the rad fan doesn't turn at all during overheating as the temp gauge moves all the way up

4 - At normal engine temp the rad fan DOES turn as soon as the a/c is turned on, but I've only observed this so far at normal temperatures.

5 - During the times it overheats and the a/c is on, the cabin vent air gets hot and humid right when the overheating occurs. I haven't yet made it a point to check the rad fan at this point to see if it's still turning.

6 - During testing, after getting the engine temp up to idle hot and the temp gauge read normal in the middle, to trigger it to overheat I had to run the engine at 2k rpm for over 5 mins before the dash temp gauge began to rise. After the gauge begins to creep up I've let off the gas but the temp continues to go all the way up. Although to trigger the overheat condition I ran it at 2k for a while, it DOES overheat by simply sitting in park and idling.

7 - The coolant reservoir cap has a small leak but I don't think this is a major factor. I've continued to top off the reservoir throughout my testing and overall there doesn't seem to be much coolant leaking from the reservoir. Although, you CAN hear air seep from the reservoir cap when you squeeze the top rad hose.

 

The main problem seems to be the rad fan not turning. Any ideas? I'm all ears.

Change the degas bottle cap aka radiator cap.

The fan not coming on is your main issue. When head temp

Gets over 230 the fan should be screaming. It should start on low about 212-220. When I get a min Ill have to look at the fan diagram and give you some steps to see if the fan module is bad or something else.

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Yes thanks fordtech1 I'll be replacing the reservoir cap, thermostat and flushing the system here in an hour, but I'm almost sure my main problem is the fan not coming on.

 

If you could give advice on how to test the parts responsible for turning the fan on I would greatly appreciate it. I have a multi-meter but need sort of specific advice on how to set it to use it. No real formal training with it.

Edited by bradleyheathhays

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I havent had time to really set you up a step by step procedure. However, that video give some information thats helpful like the power and ground to the fan and bypassing the module and applying power directly to the fan to make sure it runs. With that mileage and the issues with these fans, I personally wouldnt be to afraid to get an aftermarket fan and module assembly. OEM is ridiculous in pricing. Ill try and get you some more information when I have time to look in the manual and give you step by step diagnostics.

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Tested water pump and it's working good. Now, I've replaced both the reservoir cap and thermostat with new.

Then did some more testing by way of observing the fan speed when turning the a/c on and off. Fan speed seemed sluggish as if it wasn't being properly commanded. At different points it seemed like it wanted to turn but would stop. Maybe a dumb idea but after turning the a/c off and the blades came to a stop I took a small twig and gave the blade a quick push and it slowly started going again.


So what is this a bad fan motor maybe? And if so, where do you get just the motor? Can't find it at any of the major car store sites.


I've also read the connectors on either end of the fan control module (connected to the fan body) can get corroded.

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For something like that I would try and see if I can find a working one in a junkyard.

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Apply power and ground to the fan motor directly. If it starts up and runs full speed then chances are its the module. If it doesnt then the motor is bad.

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https://www.rockauto.com/en/catalog/ford,2011,crown+victoria,4.6l+v8,1447583,cooling+system,radiator+fan+assembly,2181

 

They are available at advance and rock auto for good prices. OEM has come way down for just the fan. They used to be $500+. Rock auto has one with controller for $90.

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https://www.rockauto.com/en/catalog/ford,2011,crown+victoria,4.6l+v8,1447583,cooling+system,radiator+fan+assembly,2181

 

They are available at advance and rock auto for good prices. OEM has come way down for just the fan. They used to be $500+. Rock auto has one with controller for $90.

 

For $90 that's a no brainer - get both.

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