Fan relay - where to buy?

[Dylan Rymer]

Hello everyone,
I am wondering where in the world to buy a fan relay for my 2003 LS V8. Fordparts only sells the whole fan assembly ($1,000+) along with most of eBay, but for now I just need a relay and am having trouble finding it. Fan has run very loud since I changed the radiator 2 years ago, even though the thermostat, pump, and temp sensors are somewhat new.

Also, if you have any suggestions on why I have went through 3 coolant reservoirs in the past 2 years (besides the possibility of a bad head gasket) it would be much appreciated. Ford dealer claims there is no excess pressure in the cooling system. Could air trapped somewhere in the system be causing it to bust all these reservoirs, or should I abandon ship while it has 120,xxx miles? The only time it overheats is when I have a coolant leak; any other time the worst temperature it ever gets is a hair above the halfway mark.

Summary:
1. Where to buy fan relay
2. Potential reasons for loud fan, considering information given above (It runs wide open even when there are no leaks)
3. Potential reasons for car eating coolant reservoirs left and right (been using aftermarket reservoirs from Advance Auto)
Thank you for any tips or lessons to impart.

 

[joegr]

1. There is absolutely no fan relay on the LS. Why do you believe that there is one? The fan motor is electronically controlled. The electronics are in the fan motor.
If the fan runs when you turn the key on, but with the engine off, then you have a bad wire between the PCM and the fan, a bad PCM, or a bad fan motor.
If the fan does not run with the engine off, then the fan is being controlled by the PCM and the PCM is setting it high for some reason.
What speed is the fan at when you first start the engine in the morning?

2. The PCM will set the fan to high if the engine is overheating. Note that overheating starts before the temperature gauge moves past the halfway mark.

3. It is very very well known that the aftermarket (usually Dorman) bottles only last about six months. Go get a Motorcraft bottle (and a matching cap) and you will be good for six years. Be warned that you also need to replace all the rest of the plastic cooling system parts.

 

[Dylan Rymer]

1. There is absolutely no fan relay on the LS. Why do you believe that there is one? The fan motor is electronically controlled. The electronics are in the fan motor.
If the fan runs when you turn the key on, but with the engine off, then you have a bad wire between the PCM and the fan, a bad PCM, or a bad fan motor.
If the fan does not run with the engine off, then the fan is being controlled by the PCM and the PCM is setting it high for some reason.
What speed is the fan at when you first start the engine in the morning?

2. The PCM will set the fan to high if the engine is overheating. Note that overheating starts before the temperature gauge moves past the halfway mark.

3. It is very very well known that the aftermarket (usually Dorman) bottles only last about six months. Go get a Motorcraft bottle (and a matching cap) and you will be good for six years. Be warned that you also need to replace all the rest of the plastic cooling system parts.

After a cold start, the fan runs normally, then works its way up to full speed in a few minutes (sometimes 5 minutes, other times 30). This happens regardless of weather, driving habits, and A/C on/off. So considering what you said, the PCM must be doing it on purpose. I just don't get why it started doing that after replacing the radiator (which is also aftermarket but looks similar to factory).

I guess there's a reason the aftermarket bottle is cheaper... Thanks for the info!

 

[joegr]

The PCM looks at vehicle speed (no need to run the fan if going fast enough), AC use, cylinder head temperature, and coolant temperature to decide what fan speed to use.