Fan problem - what do I need

[Ringmaster]

My 03 V8 Sport's fan sound like it's running at full throttle all the time now. I'm assuming it's the hyd. design. The car is not over heating. When this occurs what parts might I be looking at? The pump? I've heard people mention an actuator, a relay? I'm also assuming it's not the fan motor if there is a motor since it's spinning. How long can I run like this before I get it fixed. I don't want to make it worse. Thanks.

 

[LS4me]

My 03 V8 Sport's fan sound like it's running at full throttle all the time now. I'm assuming it's the hyd. design. The car is not over heating. When this occurs what parts might I be looking at? The pump? I've heard people mention an actuator, a relay? I'm also assuming it's not the fan motor if there is a motor since it's spinning. How long can I run like this before I get it fixed. I don't want to make it worse. Thanks.

The '03's and up use an electric fan.

 

[PetesSweets86]

+1

 

[Ringmaster]

OK so I have electric fans. What could be the problem then? Is there a temp. sensor that could be going bad? BTW this seems to be an intermentent problem at this point.

 

[SoonerLS]

The 2nd Gen LS has a variable-speed electric fan with a fan controller; IIRC, the controller is itself controlled by the PCM.

If it's only happening intermittently, the first thing I would do is clean the radiator--particularly, pull the plastic cover over the radiator and make sure you flush out all the accumulated dead bugs, leaves, and other detritus. The car may not be overheating, but if the air isn't flowing freely through the radiator, the engine will be hotter than it should, and the control systems will kick the fan up to high speed.

 

[owlman]

The fan is directly controlled by the PCM. Here's what the service manual says:

The PCM optimizes fan speed based on engine coolant temperature (ECT), engine oil temperature (EOT), transmission fluid temperature (TFT), intake air temperature (IAT), or air conditioning requirements. When an increased demand for fan speed is requested for vehicle cooling, the PCM monitors the fan speed through the Hall-effect sensor. If a fan speed increase is required, the PCM outputs the PWM signal to the fluid port, providing the required fan speed increase.

so, it could be any of those parts or sensors....
You should probably get scanned for trouble codes, that would help if the car threw one.

 

[SoonerLS]

That sounds like it's talking about the hydraulic fan on a 1st Gen LS when it references the "fluid port."

 

[owlman]

D'oh, you're right, that's for the cooling fan clutch :slam I wonder why that's in the 06 manual?
Anyway the in the gen II the PCM probably still uses those same sensors to activate the fan.

 

[SoonerLS]

D'oh, you're right, that's for the cooling fan clutch :slam I wonder why that's in the 06 manual?

I'm not sure, but AllData also includes information on the hydraulic fan in it's info on the '04 V8, even though it states that the LS uses a variable-speed electric fan.

Anyway the in the gen II the PCM probably still uses those same sensors to activate the fan.

I'd bet you're right about that.

 

[Ringmaster]

Thanks for the replies and suggestions. I removed the radiator cover and found a pretty good sized area of acumulated fuzz and misc. debris on the top front of the radiator (maybe about 8" wide and 4" high) plus some leaves along the bottom. I hosed all that off and then hosed the air conditioner compressor off from the front. The high speed fan problem is still there. It starts about 10 minutes after you start driving. Temp. gauge is still normal. No engine light. Any ideas of anything else I can check. Thanks.

 

[SoonerLS]

Some temp gauges are just glorified idiot lights; I don't know if the LS's is one of them, but you might try adding an aftermarket temp gauge and see if the fan speed does correlate with engine temperature. If it does, check the radiator cap and the degas bottle cap to see if they're holding pressure; if not, replace the cap that's failing.

If the fan speed doesn't correlate to engine temps, I would guess that it's either the fan itself or the variable speed fan controller, but I can't find a part number for the controller (Max from 5 Star Ford should be able to help with that). Once you get past the fan controller you're back to the PCM, and I don't think it's the problem. As owlman said, it could also be any of those sensors giving a false reading--it may not be reading hot enough to trip an overheat warning, just hot enough for the PCM to kick the fan up to high.

 

[joegr]

Thanks for the replies and suggestions. I removed the radiator cover and found a pretty good sized area of acumulated fuzz and misc. debris on the top front of the radiator (maybe about 8" wide and 4" high) plus some leaves along the bottom. I hosed all that off and then hosed the air conditioner compressor off from the front. The high speed fan problem is still there. It starts about 10 minutes after you start driving. Temp. gauge is still normal. No engine light. Any ideas of anything else I can check. Thanks.

If you have the AC on, and it is more than 40 degrees out, then the fan runs at full speed except when you are driving at a good speed.

 

[02LincLS]

^ Yep. I think that's true whenever the "A/C" light is on (once again unless you are traveling at a good speed). I also think that's true when running the front defogger even though the "A/C" light is not lit, it's still running the A/C compressor.

 

[Ringmaster]

I'm sorry I've been slightly wrong on the temp. thing. I drove the car yesterday (my wife usually drives this one) Lets say the normal position of the needle on the temp gauge is at 9:00 or slightly below. Now since this fan problem started the needle on the gauge is at 9:30. So it's slightly overheating if you consider 9:00 as normal. I'm thinking this might be a good thing since the fan is coming on for a reason and not some high dollar computer problem. Anyone think it might be the thermostat? The car has 124k on the odometer. Are thermostats a known failure item?

 

[joegr]

When was the last time you had your coolant flushed? Thermostats are often replaced, but rarely the problem.

 

[Ringmaster]

I checked our records and the cooling system was flushed at 100K. The car now has 124K. Would/could coolant go bad in 24K miles? On a side note I changed the spark plugs last week and I noticed that we had them changed the same time we had the cooling system flushed. I thought the old ones looked too good when I pulled them out. #$%^&

 

[Ringmaster]

Just a followup to let the group know that a new thermostat solved this problem. I installed a new thermostat this weekend and the full speed all the time fan problem is gone. Thanks all for the input.