GTO Fan Relay How-To: Part 1

So a few months ago I was able to sneak out of work a few hours early. Having some time to kill, I called up my buddy and we decided to meet at a local pub for some beer and food. Nothing crazy, just an excuse to spend a couple of hours chatting. I jump in my GTO and head over. Now, I want to paint this picture as accurately as possible. To begin with, it was brutally hot outside. Actually, to say that it was brutally hot would be an understatement. If a door to hell had opened besides me I think it would have felt like a light breeze. Plus, I don’t remember the exact occasion, but traffic was horrendous. What should have taken approximately 20 minutes turned into an hour commute in hell (because, you know… the heat).

With the stage set, let me add some details regarding the GTO. I drive the GTO mostly during the weekend, but for some time before this I had been using it to commute. My commute, while not short, can be categorized as reasonable. Approximately 15 to 20 minutes. This, combined with the GTO’s excellent cooling fans, a lower temperature thermostat and a relatively new radiator would allow me to get to and from work with the car barely reaching operating temperature. As such, as I was on my way to the pub, about 30 minutes had gone by before the temperature gauge caught my eye. While she’s typically at about 180 to 190 degrees, the Goat had crept up to around 210.

Some of you might be wondering why 210 degrees would catch my attention. After all, isn’t 210 the normal operating range for most modern cars? That, of course, is true. However, given that I live in the South and never see temperatures below 40 degrees, I had swapped the thermostat over to a 180 degree model and adjusted the car’s programming accordingly (fyi, if you don’t adjust the programming you’ll throw off the car’s tune). As such, while 210 degrees is well within the car’s operating range, it’s enough to draw my attention.

Due to the nature of the traffic jam around me, and the rising temperature, I was beginning to grow concerned. I figured I could be at the pub in a few minutes though if the road cleared up. It, of course, did not. Instead I was locked into a single lane as construction pushed me away from my destination, forcing me to backtrack and waste valuable minutes as the car idled softly forward. By this point the gauge had passed the 210 mark. In order to buy some time then I turned off the A/C, lowered the windows, and blasted the heater.

Let’s stop for a moment and segue quickly on the way a car’s heater works and why it can buy much needed minutes amidst an overheating scenario. When you turn on your car’s heater the fan draws in the outside air and runs it over a heater core. The heater core is in essence a miniature radiator. It takes the same coolant that is flowing through your cooling system and pumps it through the core. This coolant is heated by the engine and as such is an excellent source of heat from which to warm up the air flowing from you’re A/C ducts. As the air flows through the heater core, the ambient temperature that is transferred to the air is removed from the coolant. In essence cooling the liquid. When your car is overheating what is actually occurring is that the liquid pumping through it is too hot. As such, by turning on the heater you’re allowing it to cool down a bit more before cycling back through the engine. Doesn’t sound like it’d be that effective, but it is.

So I’m still stuck in traffic, the heater is blasting, the world is melting outside, and I’m about to spontaneously combust. Even with the heater on it’s clear that there’s something wrong as that temperature gauge is showing me no mercy. Normally in a scenario like this you’d just pull over and let the car cool down, but like I said traffic had forced everyone into a single lane due to construction. As the minutes rolled by and the gauge kept getting higher and higher, my anxiety was shooting through the roof. At this point I had passed the pub, but could still see it out of the corner of my eye. With the gauge about to start screeching at me in any moment I concluded that I couldn’t wait any longer. Against the immediate safety of the car, but with its long-term wellbeing in mind, I jumped the curb and pulled a U-turn while cutting off a number of oncoming cars. No easy feat in a lowered sports car. Luckily the oncoming cars were very nice and allowed me in. I figured the worst that could happen is that a cop sees me and pulls me over. A fair trade as I’d at least be out of the death cue that was my prior lane and have a chance to turn the car off.

Luckily the sound of sirens never came. I was able to drive the few short blocks back and pull into the pub without hitting a terminal level. As I turned off the ignition a flood of relief came over me. The GTO had made it without experiencing any significant damage. She’d now have a few hours to cool off and I’d be able to drive home after sundown, greatly diminishing the chances of a repeat scenario. With that I closed the door, drenched in sweat, and went into the pub to cool off.

In the next post I’ll go through the steps of diagnosing and ultimately fixing the overheating issue, as the repair turned out to be as unpleasant as the initial ride. 

Continue to Part 2 Here!