I have a 03 mini and my A/C seems to turn off when I stop at a light. Interior panel says its on, but I get hot air. Once I get moving again it starts to get cold. Sometimes the temp gauge is pegged and the red light is on. Any ideas?

 

DANGER, Will Robinson!


If your temp gauge is pegged and the red light is on, your engine is overheating
and you may end up with a warped head, leaking head gasket, or blown engine.


Check if your coolant is at the right level, and if your radiator fan is working at both
the low speed and high speed levels.


The high temps could be causing the a/c problems, or you could have a separate
a/c problem also.

 

I'm surprised I havent blown the head gasket. Its been pegged more then once. The fan does come on. Not sure about both speeds though. I've replace the resistor the turns the fan on. When I dont have the A/C on temp stays in the middle of the gauge. he fan is on when I shut the car off. I replaced the condenser last year.

 

Definitely don't keep driving if the vehicle is overheating. I had a similar instance where my heat would only blow hot while in motion, but once stopped at a light it would blow cold. It also fluctuated in heat a bit. Turned out to be a bad seal on my radiator cap, which was allowing air into the system. Others would say bad head gaskets, but I knew that wasn't the circumstance in my case. I'd first check for leaks in the system as it seems as if there is air getting into it somehow.

-Luccia

 

I will check the antifreeze level once it cools off. Why would having the A/C on cause it to over heat?

 

In my opinion, I think having a leak in the system which allows air in is what is causing you to overheat. Like said above, the A/C could be a completely different issue. I could be wrong, but just an idea.

-Luccia

 

Your air conditioner, when turned on, draws a load from the engine. The engine is working to turn the pulley that drives the compressor. Also contributing to it, is your A/C's condenser. Which is the radiator-like (actually, it is essentially a radiator) thing that sits in front of your car's radiator. When you run your A/C the condensor gets hot and must be cooled off via air flow in addition to the cooling system's radiator.

If your AC is heating up beyond a controllable temp, it will cycle on and off. Check your fluid levels and fan stages.

 

coolant level is at the cap and the overflow is at the low mark. It was that way the last time I checked it. I'm not sure how to check the fan other then its off and on. What are the A/C gauge readings and how much Freon is in the system. Could I have to much or not enough Freon causing the on and off of the compressor?

 

Well I had the car running at idle with the A/C on and the compressor cycled every 1-2 minutes. The compressor stayed on for a few seconds. The fan never came on. Temp was in the middle of the gauge.

 

Your low speed fan (stage 1) should come on a few seconds after the AC is turned on. Sounds like the resistor is bad. If even the 2nd stage did come on you may have a bad relay or fan motor. This would explain why your car is overheating.

 

Thanks I will get a new resistor. I did buy one off ebay last year. Is there a better one out there? Maybe look in to a new fan as well. I bought this car with the motor and tranny all apart. The A/C has been a problem since I put it all back together.

 

Ouch...DO NOT DRIVE WITH A RED LIGHT!!
sounds like you have a fan issue...
On the pre-2005 cars, unmodified, the PS fan and radiator fan share a fuse...
The PS fan typically vets "stuck" and blows the fuse, then the radiator fan stops...
So YOU HAVE ZERO FANS COOLING THE MOTOR!!
if you drive more than a couple times with a RED TEMP light, SEVERE DAMAGE can occur...
The least $$$ of which is a failed head-gasket, about $2000....but the block and or head can warp, and the motor could siezs or fail, resulting in about $5500-6000 bill....
Did I scare you yet??
go check the fuse, your coolant level, and spend the hood, turn on you AC...if you don't hear a fan turn on...you need to replace a ¢2 FIVE amp fuse, and a $200 PS fan....

 

" Sometimes the temp gauge is pegged and the red light is on. "

Don't drive it +2 , you will overheat more and then cook the head gasket or worse.

Check the fuse and the fan. Check the coolant, look for leaks.

 

I check the coolant again it was good, fuses were good. Connected a battery charger to the fan and it turned on. Tested the voltage at plug and had voltage there both red wires. Plugged the fan back in and it came on with the A/C on. Let it run for better then a half hour. The fan and the A/C compressor stayed running the whole time. Turned the A/C off and the fan stayed on. Going to drive it to work tomorrow and will see what happens. Hopefully it was just a bad connection. Thanks for all the advice.

 

So the fan DOES run....
ok....next we need to consider the water-pump/sc PTO gears might be in the end stages of failing....but before we jump to that conclusion, might be worth checking for leaks...bleeding the cooling system, maybe even changing the thermostat...getting help from a pro might be smart before spending big $$$ on a fix suggested on the net....
Notice any changes is sounds lately? Draggy-chain sounds or high pitched grinding sound...these sounds are typical IF the SC PTO has run dry, and the gears that run the water pump are almost dust....
Often many folks get OCD over fear of this happening...it DOES happen, but not nearly as frequently as some threads might lead one too think...
Just BE careful....if the temp maxes out..shut it down..let it cool....
check to see if HIGHER RPMS at a traffic light helps...and listen for the RADIATOR FAN..if that is ON (it is electric) the higher rpms MIGHT pump a bit more water with a failing waterpump/gears and you might see the temp drop....might be enough to get it home or to the shop ONE LAST TIME...

 

I will park in a different spot at work and see if I get any puddles. I havent noticed any new noises. The water pump and motor is from another mini with around 90K miles on it. The original motor was missing to many parts, but I do have the original head which is rebuilt. So if it does ever blow a head gasket I have all the parts to fix it. I just hope I never need it.