Fan Actuator bad???

[jsaleen]

02 LS V8. Weekend driver. Started it up one Saturday and it sounds like the fan is running full speed. Like the sound it makes when overheating. A/C off and normal temp. Seems intermittent at times. Some times no sound on cold start but will later appear again after driving for a bit. Which would be normal in the case of overheating but it's not. And there are times I do a cold start and the fan sounds like it's running. Higher RPMs and you have yourself the sound of a turbine engine. Again, A/C off and normal operating temps. And is there anyway to trouble shoot this? Thanks in advance

 

[fudge12]

Here's a list of possible problems:
*You may be actually overheating. Check plastic cooling parts. Check coolant level. Bleed system.
* You maybe have a bad actuator stuck in the open position.
* you may have a problem with the wiring to/from the PCM
* A bad PCM (Least Likely). The actuator looks for a pulsed ground from the PCM that sets the fan speed.

Your best bets is to do a thorough bleed the system, replace thermostat and broken plastic cooling parts, and refill with coolant.. If same results, proceed.

Now saying that, check your fan fluid as it should be RED. If it's any other color such as pink (common) or brown, etc... change out the fluid. Disconnect the return line from the fan pump and spin the fan until fluid comes out the hose, drain into a basin and dispose accordingly. Reconnect the return line, fill back with the proper ATF (I forgot the exact kind, but other members should chime in here with the right one) and run a can of seafoam in there. Now granted that the seafoam does do the trick of getting the actuator unstuck, drain out the fluid one more time and refill with new fluid without seafoam. (I do not speak for seafoam products. Other users have reported great success with them and I am passing the info along to you; do this at your own discretion) If same results, proceed.

As far as wiring goes you can disconnect the fan actuator via the wiring harness, and see if the fan returns to low speed. If it does, there may be a problem with the wiring from/to the pcm or a problem with the PCM. Note that the fan will NEVER stop spinning as long as the engine is running. If same results, off to the dealership.

 

[jsaleen]

It's more than likely a stuck actuator. All the other stuff you said, well let me just say I'm no noob and would never or even need to bring my car to the dealership for repairs. But thanks for the 2 cents.

 

[Telco]

It's more than likely a stuck actuator. All the other stuff you said, well let me just say I'm no noob and would never or even need to bring my car to the dealership for repairs. But thanks for the 2 cents.

Could be, but things to consider: the LS temp gauge stays in place until it's on the verge of melting down, then it will shoot up. In other words, the dash gauge is NOT accurate for any temp over normal operating temp. And, the cooling system was made with plastic that is not suited for pressurized heat cycles. It does and will fail but you won't see where it breaks. Common breakage points are the inside of the thermostat housing which uses a thermostat that applied spring pressure to plastic arms that are part of the housing, and the degas bottle which cracks but as the degas is inside its own well these cracks are not easily seen. You really do need to spend a little time checking out the cooling system. Cooling system parts can be expected to last around 80K miles, although some here say theirs has lasted as long as 150K miles. My own system lasted about 110K miles.

 

[joegr]

Could be, but things to consider: the LS temp gauge stays in place until it's on the verge of melting down, then it will shoot up. In other words, the dash gauge is NOT accurate for any temp over normal operating temp. ...

It's accurate, it's just not precise since it is highly buffered. This does make it misleading. I don't like it, but it seems that most cars are this way now.

... And, the cooling system was made with plastic that is not suited for pressurized heat cycles. It does and will fail but you won't see where it breaks. ...and the degas bottle which cracks but as the degas is inside its own well these cracks are not easily seen. You really do need to spend a little time checking out the cooling system. Cooling system parts can be expected to last around 80K miles, although some here say theirs has lasted as long as 150K miles. My own system lasted about 110K miles.

Agreed.

... Common breakage points are the inside of the thermostat housing which uses a thermostat that applied spring pressure to plastic arms that are part of the housing...

Actually, his gen I has a "normal" single piece thermostat.

 

[jsaleen]

I really didn't know I had to specify. I already rebuilt the cooling system after I bought the car and realized the Degas bottle had a crack in it. So yes I am all too familiar with how the temp gauge reacts in that situation. I also know the simplicity of being able to tell that the engine is hotter than normal. Sorry, these recommendations about over heating crack me up and piss me off a little at the same time. Do I really have to specify about the many years experience I have building engines, restoring cars, etc etc? Jesus Christ man, you would think by the comments one didn't know how to check the fluid level in a degas bottle. And I will repeat from the original post. The fan is running (like it's overheating) as soon as I start the car when cold.

I also spent some time going through the forums reading about the fan issues before creating the thread. How I even found out there was a actuator that could be bad.