Engine Gets Hot // Cooling Fan Doesn't Activate

[tonycortado]

I've got a 2005 in awesome shape, but just started having some trouble with the cooling system / radiator fan. The car warms up to just over 1/2 on the temp gauge (I don't know the actual temperature), and the fan never kicks on. The thermostat was replaced a few weeks ago. I took out the relay and jumped the hot wires and the fan turned on, so the fan works. I swapped with a working relay (just used the blinker one which is identical), and it didn't change anything. So I got under the car, and painstakingly replaced the coolant temperature sensor / switch, but that didn't change anything either.

So my questions are:
1.) How hot on the temp gauge does your aveo normally show? Is 1/2 right?! Other cars I've owned stayed at 1/4 or maybe 1/3, tops.

2.) If 1/2 is normal, when does your fan normally turn on? While idling? Driving? A/C? Hot outside? What if it is cold outside?

3.) Is there anything else I could be missing?


Thanks for all your help!

[Newborn]

1. About halfway is the norm yeah.

2. It turns on whenever the engine gets to about halfway. Regardless of ac being on, or idling.

3. Replace the fan?? For these cars they should be relatively cheap on eBay.u said it worked, but maybe a new fan will do the trick?

[avguy]

Search is your friend. Here's a prior thread with relevant information. But it's not going to help you much unless you're willing to try diagnosing using a multimeter and (if necessary) an OBD realtime data stream reader.

Overheating...Resistor?

[Jiggs]

Just had my thermostat and housing replaced.

On the way home it started doing some whacky things. Temp gauge red lined, wasn't blowing any hot air, fan wasn't activating....turned around and went back to the garage. Mechanic apologized, forgot to tell me that their would be air in the lines and it would play havoc with the gauges & temp sensor for a bit.

Cure....burped it. Shut it down, let it cooled a bit then added some more coolant.

In the past 24hrs I've had to do this 2 more times but now its working fine. Gauges back to normal, fan kicking in when it should...and the heater works better than ever.

[avguy]

Just had my thermostat and housing replaced.

On the way home it started doing some whacky things. Temp gauge red lined, wasn't blowing any hot air, fan wasn't activating....turned around and went back to the garage. Mechanic apologized, forgot to tell me that their would be air in the lines and it would play havoc with the gauges & temp sensor for a bit.

Cure....burped it. Shut it down, let it cooled a bit then added some more coolant.

In the past 24hrs I've had to do this 2 more times but now its working fine. Gauges back to normal, fan kicking in when it should...and the heater works better than ever.

I've read some fairly ugly stories about shop work, but the above is right up there with the very worst. How can anyone who claims to be a professional mechanic do and say what he did? There have been many DIYers over the years on this forum doing various jobs which require coolant drain-and-fill, and VERY few of them have been as stupid as this 'professional'.

We're not talking about something like a gen 7 Honda Civic here. The cooling system on these Aveos is NOT difficult to get the air completely purged, and it should only take one time to get the job done correctly. The fact that this guy messed up such a simple job might have resulted in head gasket damage on your vehicle. I recommend that you do a compression test, in order make sure that has not happened. and hold him fully accountable if it did. Really dismal to read something like this.

[xintersecty]

I had replaced my resistor last year

Here is the picture of the location


And the part number

[Jiggs]

First of all there is approx 40% or better of coolant left in the engine block as it was never "drained" for this repair.

They did bleed the system after the repair however, and I'm sure most mechanics will agree and from what I've read about cooling system repairs, is that it's very possible and common to still have air in the system that needs to come out and will come out during normal operation even after a bleeding procedure. Sometimes the procedure has to be repeated more than once.

In my particular case it was obvious that there was still air in the system due to the improper sensor readings (red line to cold in a milliseconds) with the car not even up to normal operating temperature (esp on a cold Canadian winter morning).

When I returned to the garage they added about 2 ounces of coolant. Still coolant in the reservoir, it wasn't bubbling or boiling. They ran the car for approx 10min more, checked the coolant level, checked on the lines again and all was well. No more whacky gauge readings, heater working properly etc, no sign of any further air pockets.

Since then I've added a couple of more ounces. No whacky readings, 100 hard miles today coolant level hasn't budged a millimeter.

So no, it wasn't a calamity, catastrophic failure or glaring mistake. There was an air pocket and that was that.

The original intent of this post was to bring to the attention of the OP was if he did a thermostat repair then there was a very good possibility that there maybe air possibly a lot of it in the cars cooling system that could be responsible for the improper temp readings.