The fan that has a mind of its own

Engine Fan Closer to the battery

Original Issue:
I noticed some coolant in the engine bay and a slight crack in the radiator so i thought the radiator is stuffed. Then later on the car would ever so slightly heat up during traffic then cool down.
1st attempt at fixing:
Changed radiator and then discover that the low speed on the fan has burnt out so changed that too. High speed would cool the car down when the temp went up.

Second problem:
The fan low speed doesn't turn off. This is why I suspect that it burnt out in the first place. When cold it doesn't turn on, but once the car heats up it is always on when i come to a stop.
2nd attempt at fixing:
Changed both the sensors near the thermostat.

Fan continues to be on! Problem not gone away, fuel consumption has gone up.

Any help or ideas really welcome......

Thanks.

Try swapping the lo speed relay for another.

yep today on my way to work i'm going to buy all 3 relays and swap them over. Figers crossed!

There are 3 relays there which control the fans - high/low and second fan i take it. which relay is specific to the low speed fan?

The wiring diagram says it's the one second from the rear on the passenger side of the car. Before you buy new ones I'd swap them around - make sure they have the part number on the top of the relay. If that operates correctly then just buy one. If it makes no difference then the problem may not be the relay sticking, but usually it is.

Thanks mate, i'll try and sort this one out tonight- hopefully this is the missing part to the puzzle :)

ok tonight changed all 3 relays and still no luck...... is there anything left in the cooling system which could be causing this ??!!

slowly having enough of this now!

iirc the auto's will run the fan when warm

Sorry, what do you mean by that? How does the auto's run the fan?

My TL auto will only run the fan when the engine is a fraction above it's normal operating temperature which is just below the halfway mark on the gauge. The fan never comes on when the car is warm or at "normal" operating temperature. Once the car stop in traffic with the engine at operating temperature, the fan will come on after a few seconds due to the lack of cooling air through the radiator and then will cycle every few minutes as the temperature goes up and down. Once moving again and air is flowing through the radiator again the fan will switch off.
Running the A/C will activate the A/C fan but only when the compressor is engaged.

The autos have a transmission cooler which is the lower part of the main radiator which is cooled by the main fan when stationary.

Just behind where the top radiator hose joins the engine at the thermostat housing are two sensors - the Water temperature gauge unit sensor and the Water temperature sensor....the latter has 2 wires in the connector and I'd guess that this sensor is the one that tells the ECU when to turn the fan on/off as the engine temperature varies. One of the symptoms of a bad temp sensor is bad fuel economy as the ECU uses this information to (in part) decide how much fuel the engine requires to operate....cold engine requires a richer mixture etc.
I've been unable to find a test procedure in the manual but one must exist!
In you original post you mention that coolant leaked out - if coolant enters electrical connectors it can become corrosive and cause all sorts of strange electrical problems, so I'd also disassemble all connectors that may have gotten wet and flush with clean water, dry and reassemble.
The transmission oil cooler in the bottom radiator tank is cooled by radiator coolant which is then cooled by the radiator fan or by the forward motion of the vehicle.
Hope most of the above is correct.
Good Luck.

thanks hako, yep i might try and inspect the contector. i must say though, it was more of a dribble and lot more water goes there when i clean the engine. Still worth a shot!

It is really strange, today, when i was driving and stopped the fan didn't turn on. As an experiment i turned on the A/C and both fans started spinning...... then once i turned it off (A/C), the larger fan kept working.

Sounds like it is turning on correctly (maybe) just not turning off correctly.....

In the end i booked it in with Mal for him to have a look.

Quick question, is there a way to put the ecu into diagnos mode so see if it sensor related?

Cannot help you there....have you checked in the downloadable manual? Please report back what Madmagna finds.

Ok just wanting to close the loop on this issue, took dads car for a spin and noticed that a magna will have the fan on for most of the time lol my car was turning on and off so its just the car really.

Mal did hook my car up to the comp to see why it was burning so much fuel and it seem the oxy sensor was stuffed, so bought a new one and hopefully all sorted now

Not wanting to make this long thread but hopefully it helps if someonce does a search in the future.