|
|
| Coolant Temperature Sensor |
 |
|
Well, this piece of maintenance work was a different experience, since I didn't do this job on my car. I was, instead, working on the car of a woman who works with me. She has a 93 SC2, and it had been overheating while she was driving around. There are a number of things that can cause this kind of problem, but in general, whenever something goes wrong with the coolant system, coolant gauge, idle, or almost anything else the car, a good place to start is the coolant temperature sensor, also knows as the electronic coolant temperature sensor (ECTS). The reason that a broken or damaged ECTS causes so many problems is because, in addition to it feeding the coolant temperature dummy gauge, it also gives feedback to the PCM that affects the air to fuel ratio, as well as timing. By this mechanism, it can cause problems with starting the car, overheating, erratic idle speeds, and a myriad of other irritating shits. Therefore, if something goes wrong, it very well may be this little thing. There are two versions of the sensor, by the way. The older version is made of a polymer, and has a tendency to break VERY often. The newer ones (and the only kind sold by Saturn now) are made of brass, and are more durable and, I belive, more accurate as well. If, by some reason you come by an older one, don't use it. Anyway, the first thing you have to do is remove the intake piping from the air box to the throttle body. Her clamps were operated by a phillip's head screw driver, which was different from my type.
|
When the intake piping is off, look down on the driver's side of the head, and you'll see about what you see to the right. On 91-94 Saturns, there are actually TWO ECTSs. You can see them both in the picture. The one in the foreground has ONE wire coming out of it, and feeds the gauge in the cabin. The one in the background has TWO wires, feeds the PCM, and is the one we are interested in. Newer Saturns have only ONE ECTS, and it performs both functions. Before we go any further, I should mention that it is generally suggested to do replace the ECTS only on a cold engine. I did it on a pretty warm one and it didn't make too much of a mess, so I'd say fuck it, but whatever. the next step is to remove the wiring from the sensor. To do this, get a pair of needle-nose pliers and squeeze GENTLY on the "ears" of the connector that holds the wiring to the back of the sensor. Do NOT pull on or near the wires. If the wiring doesn't come off easily, you're squeezing in the wrong place. Move your pliers and try again. You'll get it eventually. After the wiring comes off with the connector, move it out of the way of the sensor as far as possible.
|
The last step is the most tricky. First, open up the coolant tank to vent any pressure there, and then screw the cap back down tightly. When you remove the ECTS, a but of coolant will come out of the hole. Releasing the pressure in the coolant tank and then capping it again to create a vacuum will minimize coolant loss, even on a warm engine. I only lost like two ounces or so. To remove the ECTS, get a 13mm LONG socket and a short extension. Keeping the socket as straight around the sensor as possible, slide it all the way onto the sensor, and you'll feel it engage to a six-sided metal piece that will allow you to unscrew the sensor from the head with the ratchet. When you feel the sensor becoming very loose, use your hand to unscrew the sensor completely and quickly HAND TIGHTEN the new one back in a bit to stop the coolant leak. After the coolant has stopped leaking, use the ratchet again to screw the new ECTS back down (DON'T OVERTIGHTEN). Reconnect the sensor wires by gently pushing the connector onto the back of the sensor. If it doesn't click, rotate the connector until it is positioned correctly and snaps back into place. Reinstall the intake piping and reset the computer by pulling the PCM fuses in the engine bay fuse box for a couple minutes or disconnecting the negative battery cable for about a half hour. Hopefully your shit is fixed, kiddies. Oh yeah, I know you like that finger in the picture, too, don't you? Uhhuh. Toit.
|
|
|
|
|
|
