I've just went through replacing a good deal of the cooling system on my 2002 LS, 66k miles. Most know parts such as the LIM, thermostat (both twice in a 6 month period) water pump, radiator and joining parts, filters and fluids... lucky for buying an extended warranty, all about ~$5k in the less than a year. Well my car still is experiencing the a/c dropping out on me randomly at a lengthy stop light, or when i'm at a mid/high speed on the interstate and come to a stop, the temperature will rise a little over half way and you can feel a slight jerk in the engine and the cold air stops. Usually if I park the car for a while, it'll eventually kick back in but it's too hot for this crap now. Any ideas?

 

Cooling fan issue. It could be a relay, wiring, sensor, fans.

 

Thats exactly what I was thinking. Any high output fans for our cars?

 

You don't need high output. Just get the factory ones working properly.

 

Ok thanks, will update soon

 

Well my car has been blowing out super hot air for the last 2 days. I checked the car today, fans running fine but the radiator is full of dark brown sludge. The bottom of the radiator cap and neck of the radiator is covered in it, very thick. Now this will be the 3rd time the system will be flushed and possibly the radiator changed for a new one. I've been to two different shops, both flushed out the system now the sludge is back. Any ideas??? We know the dealership I bought it from put some sealant crap in there when I bought the car (didn't know until a month later when I had the LIM and radiator replaced) but since then nearly the entire cooling system has been replaced... I dont get it?!?!?

 

Have you had the AC checked because it sounds like the Freon is low causing the system to blow warm. Also if the cooling system had dexcool in it and regular antifreeze was added it would turn to sludge.

 

The shop checked it every time I turned it in and dex was replaced each time also I take it back to the shop today so we'll see.

 

My problem is occuring in ac mode and heat mode. Just as long as im cruising at least 30 mph my ac and heat do what they are supposed to do but if i go slower it does just the opposite, but today i noticed that if i have the blower set on the left half of the dial the air works just fine. 2007 Monte LS.

 

So your fan speeds are only working on half the dial?

Probably the blower motor resistor going bad.