I have a 2000 that has been over heating when stuck in traffic. On the freeway it stays nice and cool but I get in traffic and the temp goes up! So far I have replaced the electric fans.......no change, then I just dropped in a dewits dual core radiator as well as a new thermostat.......no change, The only part I didn't change was the water pump only because that was changed only 2 years ago. I am at a loss......... I just drove it today with the AC going for about 20 minutes around town and in that time frame I got to 241 degrees! I don't know what else it could be!

 

Have you confirmed the fans are turning on?
Did you do anything before this started? Perhaps replacing hoses, or...?

 

The fan on the driver side I cannot see it to tell if it is turning on or not the one on the passenger side though IS turning on. As far as doing anything to the car no I didn't do anything recently before this started aside from put a new stereo in the car lol

 

I'd personally start by ensuring both fans turn on when they should.

 

I would start with a infrared thermometer and verify that it is hitting those temps
a bad sending unit could give false readings
low speed fans come on at 228...hi speed at 238 (approx) without the AC running

 

Also, you did not mention if you replaced the thermostat.. I'd replace it with a 180* if you havent already.
And make sure those fans are coming on at the right time.

 

To verify both fans run you have to get under the car. Driver side fan (A/C off ) should come on at approx. 228 degrees which you can monitor with the gauges button showing coolant temp. Now turn on the A/C. That fan should come on very soon, and both fans should change to high speed. Read up on bleeding (burping) a cooling system. You might have air trapped in the system. Have the pressure cap tested or if it's original replace it. I'm not a fan of lower temp thermostats. A 180 will open too soon and not let the coolant stay in the radiator long enough to cool it down. This car should run close to 200 to 210 which is normal.

 

If the fans are not going into high speed is the only way to resolve this the PCM? or is there another cheaper way?

 

Just because you changed out the water pump two years ago, doesn't mean its okay. Follow the list:
1. Clean ...take out the radiator and really clean it. Also the A/C.
2. Check the water pump for full flow.
3. Check the hoses.
4. Change out the T-stat
5. Change the pressure cap
6. Change the coolant and replace with a 50/50 per cent of distilled water and Dex Cool.
7. What did I miss?

With the exception of the water pump, the above are all cheap and good maint.

 

ok so looking at the photo in that thread (attached above) it looks like during normal operation relay 45 controls both fans. when high speed fans are needed relay 44 closes and goes to ground so 45 is only controlling the left side fan then relay 43 engages the right side fan. This all makes perfect sense to me since in normal conditions both fans are drawing from the same circuit so they are splitting the 12 volts between the 2 fans then in high speed once 44 closes and goes to ground that puts all 12 volts to just the left fan then 43 supplies 12 volts to the right fan. This is all crystal clear to me. and typically when the fans are running at high speed you can hear those things blowing some air. now here is where I get completely stumped. I have sac city corvettes coolit in my car which replaces relay 43 and allows you to energize relay 43 at will and should supply 12 volts to the right side fan on command. While my engine is nice and cool so neither fan is running I energized the right fan with the coolit. it sounded like the fan was running in low speed mode! looking at the above diagrams that should not even be possible! before I replaced the fans you could hear the right side fan kick on in high speed now with new fans in the car it sounds like it is running at low speed! I am stumped!

 

Put the car on ramps and check the front of the A/C condenser and between it and the radiator. Bottom feeders suck up a lot of dirt. I clean mine every year before winter for this very reason. Don't use compressed air.

 

Yes. this is the issue with my car now. Just had some work done and car gets hot in traffic with AC on. Basically lots of dirt and leaves get stuck up there and block the air flow. cooling system works harder with AC on and hurts airflow. My radiator is original 135k miles and needs to be replace for DEWITT double row. about 599.00 I understand it a drop in and works with stock fans.

 

for everyone suggesting that I clean my radiator.........are you saying that the new dewitts radiator came from the factory dirty? in my op i state that I put in a brand new radiator

 

yes it is a easy drop in and does work perfectly with the stock fans!