hot days and the defroster

[erc84]

I have a 1995 3.8 V6, on hot days sitting at long stop lights or stuck in traffic, in other words sitting idle for a long time, I turn on my defroster on high, to relieve some heat on the engine. Is this a bad thing to do?
In my mind what I think happens is that the defroster just takes some heat from the engine and gets it out through the vents inside the car or is that false? Or is what I do at those stop lights/etc OK to do? I don't leave the defroster running while driving, just at long stops.
Overall is that OK?
Thanks

[Capri306]

#1. The Blue Oval Lounge isn't the forum for this kind of question. It belongs in the proper Ford Tech forum.

#2. The defrost function (in most vehicles) cycles the a/c compressor on. Therefore, the electric fan for the a/c condenser will kick on to get rid of that heat. While you may get a temporary cooling effect from the fan kicking on, you will end up creating more load on the engine, and thus create more heat. The hot air coming out of the duct is cooled by the a/c system to dry it before it is heated by the heater core. You're basically running the air conditioning system. I could liken this to running a window a/c unit in the middle of the living room: sure it's nice (for a while) in front of it, but eventually the room will become unbearably hot.

Moral of the story: if you want to shed more heat while standing still, there are more efficient ways to do it. A larger radiator and adjustable fan thermostat would be good to start with, but I would be very reluctant to put a cooler thermostat in it. This would cut down on engine life and efficiency. IMO, your vehicle should NEVER have a problem standing at idle in traffic, even on the hottest days. It's a car made in 1995, not 1932.

[Mr 5 0]

To lower the temp on the cooling system, leave the defroster alone.

Just turn your heater control knob to the red side (heat), set the dial to 'vent', open the dash vents and turn the blower on 'high' for a few minutes. This draws some heat out of the cooling system (and into the cars interior). It's going to be very uncomfortable for you but it always lowers the temp on a properly operating cooling system. I did this many times in cars with less than optimal systems and it never fails. Of course, if you have a serious cooling problem, it will only help for a short time before you eventually overheat.

FYI: I replaced my rotted-out 2-row radiator with a Ford 3-row radiator in 1999 and never had a cooling problem from that day on. The 'Police-Duty' fan I installed with the radiator probably helped, too, along with the dose of 'Water Wetter' I used. All recommended.

[reconman]

First of all a V6 should not be overheating. Using your heater core to cool the engine will work temperarally, but its not recommended, use only as a last resort. Go with a 3 core radiator and this will solve all your worries, plus its easy to install yourself. Good luck.