My 2005 Lancer ES is approaching 100,000 miles, and I have noticed that the temperature needle is moving a little more than it ever has. I used to think it was broken, as it never swayed from just below halfway once the car got warm.

Now it still usually sits right below the half mark, but I have noticed that in traffic, it moves up to right at half, then goes right back down. It's a relatively fast motion. It's been cooler out, and I haven't been running the AC.

I don't smell any coolant, and I will check my fans tonight.

As our cars age, is slightly more movement with the needle normal?

 

Not that I'm awear of.

Let us know what you findout about your fans.

 

Ok, so I ran the Air conditioning part of the way home. Very little, if any movement to the needle. I turned off the AC, and within 3 minutes, the slight fluctuation was back.

Once I was home, I let it idle for about ten minutes - no fans at all. The temp never went above halfway, but the fans did not come on - either one. When I turned on the AC, both fans came right on.

From my reading on this board, it seems like there are two different possibilities with fan issues: a relay, and a controller unit.

From what I discovered about the fans not working without the AC on, can we determine what most likely is the cause?

Thanks so much!

 

Sounds like your thermostat is about to take a dump or your water pump being that you are at 100k miles and that's just about when a timing belt, water pump, thermostat change needs to be done... be careful because if it goes and you over heat kiss your head gasket bye bye

Just read the last post you put up, sounds like the thermostat isnt opening properly if the fans aren't kicking on and eventually the thermostat is opening and cooling things down a little and not triggering your fans... Doesnt make sense for the relay to be fine with the AC running and then acting up when the AC is off...

 

Thanks for the info. The thermostat was what I originally suspected - but it seems like it could be other things since the car never really gets that hot - it just goes to the mid point. As for the water pump - I had mine replaced around 70K from the dealer. Is there anyway that I can confirm or deny that the water pump or thermostat may be the culprit?

Thanks!

 

After letting the car cool down nicely, I went out at started it again - no AC on. The fans didn't move at all, even when starting the car. I seem to recall that my fans would cycle on for a second when I first started the car. I let it sit again at idle, and the fans continued to not do anything. It does feel like the thermostat is functioning normally, and I don't see any leaks near the water pump.

I've read a few other threads regarding this fan control unit going out - and it causing the fans to stick on all the time, or off all the time, or some combination of the two. If this unit is messing up, could my AC still power up the fans?

 

I'm not a expert on the fans, but I do not think that your t-stat for your water cooling system is what tells your fans to come on at all.
I'm sure the fan has a t-stat that tells the controller to turn the fans on.

I could be wrong but I'd be surprised.

 

When I thought the thermostat may be bad, I was thinking it may be stuck open, causing that temperature fluctuation. However, right now I am leaning toward the Fan Control Module, as my fans don't move at all, even after sitting at idle for 10-15mins, unless the AC is on.

 

what you describe in your opening post screams t-stat.

 

I picked up a Fan Controller at a recycling yard today. Hopefully this one works. However, I am going to be looking into a thermostat as well. Is there anything special about changing the thermostats in the Lancer? I have done it in other cars - and usually there are little tips and tricks that are car specific each time.

 

Put the fan controller in. I don't believe it made any difference. The fans came on, but not full power, after about 20 mins at idle with some light engine revs. I put the original one back in, and same deal.

I will see if I can track down a thermostat and try that. The only other (easy) thing I could think of may be a need to bleed/burp air out. I did have my radiator flushed in May. However, I live in Arizona, and haven't had to use my heater since way before May - and I just tried to use it again around the same time I noticed the temp fluctuation. Is it possible that opening up the flow to the heater core after a flush, and many months of inactivity could have released air or anything?

 

thermostat

just had idential problems.

 

i have same problem except i changed the t-stat. now it shoots coolant into the overflow tank causing me to run low and then run hot. any ideas before i change this head gasket everybody keeps leaning too.

 

head gasket
before you do the head gasket you may want to try a new radiator cap. Maybe yours can't hold the pressure anymore.

 

http://www.youtube.com/watch?v=GbTz9YiclG8
is it like this because the same problem came out of my evo
FYI the video was at 70mph cruising no change in airflow or outside air it was about 75 degrees then outside