Title pretty much sums it up.

Fan on and no compressor - engine temp is fine.

Fan on with compressor on - engine temp goes way up, and keeps climbing....

Any ideas as to what might be happening here?

Thanks.

 

Maybe your cooling system isn't working as well as it should, and it can't dissipate the extra heat fast enough that's generated by the engine working harder with the A/C engaged? Does this happen when idling in the driveway, idling in traffic, out on the open road, or all 3?

 

Out on the open road, I am fine, because I am getting enough airflow.

What is the difference is between idling in the driveway vs. idling in traffic?

Either way, it does happen when idling at a standstill, or driving locally. Unless it's really cold outside - then when I drive locally, I am fine because of the cold air.

But the idling/driving locally issue only happens after about 1 hour. I can drive locally, or be stuck in traffic for about 1 hr, with the fan on and with the a/c on, and I am fine. After 1 hr, is when the car starts to overheat.

Thanks!

 

When sitting in traffic, you're boxed in between other cars, sucking in other's exhaust/hot engine heated air, no fresh air to speak of. In the cold of winter, you shouldn't have problems, but sitting in traffic can make things much worse in the heat of the summer. Maybe your radiator isn't flowing/cooling very well, and a back-flush is in order. Do you have a thermostat in place, and working ok?

 

Aside from the temp gauge, can you verify otherwise that it is overheating? I only say this because being that your temp gauge is a sending unit style gauge, backfeeding of electricity into that line could have an affect on the gauge reading. It seems suspect that the a/c compressor would cause the engine to work that hard that it overheats. Possible, but unless the compressor itself is having an issue that causes it to turn hard it seems unlikely.

 

what is the temp actually at? 220 is normal for these cars. also, have you ever cleaned out the condenser and area between the condenser and radiator? if not, clean it. also, is the coolant fresh? if not, drain it, remove the rad and clean it out the easy way

 

Ah, gotcha!

How do you do a 'backflush'? And I assume I have a therm that is working ok....here is what happens:

I start the car, and after a while, it gets up to 220. Then, the temp starts to come down a bit -and this is without the fan kicking in yet. So it sits at about 200 for quite a while. So, everything seems to working as it should there. But later on after 1 hr, is when the car starts to get too hot. So you think that maybe the cooling system works good at first, and then stops working properly?

 

Yep - 220 is normal here. Have cleanes the condenser area, and the coolant is about two-three months old.

No. I wouldn't want to wait until I start seeing smoke...afraid something might get damaged. I guess it could be the gauge, but the gauge is acting as it has since 18,000 miles. Any way to do some other type of verification?

Thanks guys.

 

flush the system well!!! If you don't know how, pay to get it done. Pressure test the cooling system

put the air dam back underneath the car

replace the fan with a high speed high volume single or dual fan unit


if the problem still occurs and the gauge is accurate, then you have a a coolant flow issue internally in the engine and that's why you flush the coolant regularly.

 

I did not see what fan setup you have, but if the A/C is turned on, the fan should turn on as well. If it doesn't there is an issue. Please note that there is some variance in what temp the fans turn on at, but it is in excess of 220*. If you have no coolant loss, and have no internal restrictions, along with a properly working fan, and a properly pressurized system, you don't seem to have an issue. For example, my 2010 dodge ram quickly reaches operating temperature (200) and remains there the entire time I drive it. My 87 camaro takes FOREVER to get to 160, but when it does it reaches 195 quickly and my fan turns on at 190 and off at 175. In the winter I can drive it 10 miles without the fan ever turning on, but in the AZ summers, it is on within 1.5miles....and I have a highly modified setup. The bottom line is that if you are at 220 without it continuing to climb, you most likely do not have an issue.