Changing the ECTS (Engine Coolant Temp Sensor)

[PurdueGuy]

Replaced my ECTS today - went very smoothly using these directions, and only about a soda capful of coolant came out (did the jacking up the driver's side, and removed & put back on the tank cap). Car seems to be running about the same, which is very well, fortunately. The engine temp still doesn't go more than a hair above 1/4, though. Will be considering replacing the thermostat next, unless gas milage improves enough to make me not bother with it.

[bgates2b]

Just curious.

I replaced my ECTS this past weekend. I noticed that the bag in the pictures shows a Saturn bag; mine was in a GM bag. Is this the correct sensor? Do multiple GM engines use the same sensor?

I am concerned because even though the engine is much smoother and quieter, I did not notice a noticable improvement in MPG. At least, not according to my gas gauge.

[EPYNGNDM]

Thanks for this, bought part and socket from Kragen. Did whole job in 30 mins with minimal coolant loss. Also cleaned connector with Q-tip to get off gunk.
Comes on now at 3/4 temperature and pulls down quickly to below half.

Thanks again, Wolfman !

[tenn734]

a big thanks to wolfman and auxmike for the instructions... much much better than any chilton or haynes manual


everything went relatively smoothly
too bad the whole job cost me $150... i went to get a 13 mm deep socket and ended up buying the a whole 100 piece mechanics set.

anyone want to buy a slightly used authentic, genuine saturn ECTS?? ill start the bidding at $25.
j/k

the old resin one has a hairline crack...i feel a lot better now witht he new brass one ...Thanks again!!

[mjo]

Just thought I might add my two cents worth. The ECTS has a 1/8" NPT pipe thread. When you tighten the ECTS, unlike a bolt, it will tighten slowly. It is easy to overtighten and some on our site have stripped their sensor because of this.

[chinch33]

Thanks for all the tips on this everyone. I changed my sensor in no time, and only 1 small drop of coolant came out! depressureized the coolant tank and jacked up driver side of car as suggested. worked great! made a huge difference in how the car runs!

[carbaugh]

I just changed the 2 sensors in my 94 SC2 (DOHC). Mine must be a weird one because it has 2 sensors, but both are TWO WIRE. I haven't noticed much improvement in the temperature reading / fan behavior. Could I have mixed up the sensors? The bottom one has a gray colored tip and is slightly longer. The top one has a ligher colored connector tip. Since these are both 2 wire, what should the colors of the wires be?

I should mention that this car has a new radiator, hoses, thermostat, and water pump, all replaced before I bought the car. The engine doesn't exhibit any tangible signs of real overheating, just the darned gauge.

Fuel mileage is mediocre, around 28mpg.

Any help appreciated!

[williammcginn]

I was lost and now am found. Changed the ECTS as per the Wolfman and the car runs great not bad for $21.02 for the sensor at the dealer, its brass thanks.
Bill
"No one looks good with brown lipstick" Frank Zappa

[Ghostrider359]

I had a feeling my old ECTS was blown...and I was correct...very correct. The tip was melted and cracked...and the connector pins were mangled! I got a new one from the dealership for about $18 plus tax.

I didnt come here to see how to do this...which was my first big mistake. I pull the old one out with the wrong deep well socket...it felt like it was contacting the nut properly...but when I began to turn the rachet more and more, I could hear something leaking...and leaking and leaking and leaking. The engine was not stone cold, but I had left it out in the cold evening for about 2 hours or so. Anyway, the first gen Saturn Haynes manual (from when we had our 'ol '94 SL2) said that all you have to do is undo the resevoir cap to release any pressure (obviously you wait till the motor is cool) and then undo the electrical connector and then unscrew the sensor. Nothing about coolant leaking...though I expected some...but I think a lot more than that came out.

I had a rag under the sensor bung to contain any leakage and it was thoroughly soaked...plus there was a good puddle under the car. Anyway...I found that I couldnt retighten the old sensor...as it was jammed into the socket...so I do my best to contain more fluid and take the socket and get a hammer (the sensor was busted anyway) and got it out...then I quickly screwed in the new sensor by hand and then torqued it down with the proper socket. Probably not the right order of things...but I was panicking.

Anyway...I checked the resevoir...and of course its empty. So I go inside and fill up a pitcher of distilled drinking water and begin filling it back up to the "full-cold" line. I make sure everything is back in place and take it out for a spin...and to be truthful...I raced someone...mainly because they were being a ******* by nearly kissing my arse for almost a mile. So when the guy in front of me got into a turn lane...I floored it to get away...and away I got...it was a second gen Neon...and by the lack of power...probably an ATX...which I dont knock, cause I had a first gen Neon ATX and loved it...but second gens are much much heavier.

Anyway...the whole time the temp needle was just a hair over the 1/4 mark and never changed. I get home from my little test and do a quick check...noticed no leaks...nothing out of the ordinary...lock 'er up and go inside. I come out later to run an errand and drive for about 5 minutes and am welcomed with the low-coolant symbols flashing...I pull over immediately and pop the hood. Again...nothing out of the ordinary...I have an LED flashlight and see no leaks...hear no leaks (I heard the original leak well before I even found it)...nothing. So I get back home and let it cool off. Of course when it was cool enough, I checked the resevoir again...and it did have coolant in it...but not to where I filled it up. It was about halfway to maybe 3/4s filled (in relation to the fill line).

Now I'm a dumbass when it comes to the cooling system...but I've always known you can add distilled water to the system. Did my little acceleration test with the Neon boil off some water? Did the system settle and it turned out that there still wasnt enough even though I filled it?

I think its time for a flush and fill and an oil change anyway...I dont seem to have harmed the car just yet...but I know if I dont keep up with this, there could be a boom...and a second LL0 down the tubes (first died due to too high of oil consumption).

Thats been my night...the fun just never ends with this car. Any help would be appreciated! And yes...if it helps you any...you can call me a dumbass!

[macaroo]

I must be missing something... I just spent the better part of an hour trying to figure out where the ECTS exactly is on my wife's 1993 SOHC SL.
1. I removed the air intake as per Wolfman.
2. located two sensors on the engine itself the slightly raised one had a single wire. The lower one had a two wires, one of which was yellow as I recall.
3. both sets of wires ran into a huge grouping of wires all tightly taped up.

By the look of the new sensor my wife purchased from Canadian Tire, (single wire, brass fittings, only about 8 inches long) I fugure I MUST be looking in the wrong place. Everyone is talking about how to pinch it out of one area and just connect it. Do you actually need to remove all the electrical tape and bundled harnesses?
Is the harness to replace this thing in the bundle of wires... that makes no sense.

The best photo i could find is here. http://img55.photobucket.com/albums/...e/DSCN0551.jpg
but as this is a SOHC, and a different year, this is not much help. If anyone can help me out on this i would appreciate it as I just sent my wife to the mechanic to get it done for 85.00 cdn. the time is 10:21am PST i have about 45 mins before committing to the mechanic.

mac

[David 93 SL2m]

The EGR valve in macaroo's picture of his 1993 SOHC SL doesn't look right. I thought the S-Series didn't start using the linear EGR valve until 1994 for some parts of the US (such as California) and 1995 for the rest of the US and Canada. What do you all think...?

Here is his picture:

[96SServiceLight]

I have a 96 SL2. Do I need to disable the air bags before replacing the ECTS?

Originally Posted by wolfman

The ECTS is a two wire sensor used by the PCM to measure engine temperature and set engine/transaxle operating parameters accordingly. On 91'-95' SOHC and DOHC engine equiped "S" series Saturns, there is a SEPERATE sensor used for the gauge. On these cars, the ECTS is the TWO WIRE sensor located just below where the upper radiator hose attaches to the engine. (The other ONE WIRE sensor nearby is used for the gauge) On 96'-02' SOHC and DOHC engine equiped "S" series Saturns, the ECTS is in the same location, but also operates the temperature gauge. (The other one wire sensor is deleted)

To change the ECTS in either case you'll need:

13mm DEEP WELL socket (6 point variety recomended)
and a socket wrench.
Perhaps a pair of needle nose pliers

Obtain the "NEW style" all brass ECTS from SATURN, it will come ready to install with nothing else needed.

DO THIS ONLY ON A COLD ENGINE!

Proceed as follows:

Remove the air snorkle running from the front of the car to the throttle body. (Or air filter housing on 91'-94' SOHC)

Locate the ECTS as described above, the electrical connector is held on by a plastic connector with two little "ears" on it that grip the lip of the ECTS. It can be hard to see. To remove the connector, SQUEEZE the plastic hood about 3/8 in. BELOW WHERE THE WIRES GO IN with either your fingers or needle nose pliers and GENTLY pull away from the engine. DO NOT PULL ON THE WIRES! If the connector does not easily release, reposition your fingers (or the pliers) and squeeze/pull again. Eventually you will find that "magic spot" and the connector will come off quite easily.

Inspect the inner portion of the connector for any signs of corrosion. If corroded, it should be REPLACED (Available from Saturn) but cleaning it can sometimes do the trick.

Remove the coolant resevoir tank cap to relieve any pressure in the system, then put it back on TIGHTLY to avoid excess coolant loss when the sensor is removed.

HAVE THE NEW SENSOR READILY AVAILABLE BEFORE THIS STEP!
Using your 13mm deep well socket, remove the old ECTS from the engine by turning it counter clockwise. Keep the socket as straight as possible over the sensor. (When it comes free from the block, some coolant will spill out, DON'T PANIC)

Quickly thread the new ECTS into the hole BY HAND to minimise coolant loss and prevent crossthreading.

Using the 13mm deep well socket, tighten the new ECTS into the engine by turning it clockwise. Keep the socket as straight as possible over the sensor to avoid damaging it. Keep turning until you feel it "bottom" in the hole but DO NOT OVERTIGHTEN IT!

You reconnect the electrical connector by placing it over the end of the new sensor and then GENTLY pushing in on it while SLOWLY rotating the connector. When everything lines up, it will then just pop into place.

Reinstall the air snorkle.


NOTES:
Coolant loss will be minimal but messy. You should NOT need to top up the coolant as less than an once or so will leak out. You "can" rinse off or mop up the spilled coolant if you wish (recommended) Keep PETS AWAY some (green) antifreeze is POISONOUS to them but tastes "sweet".

You "should" reset the PCM after changing this (or ANY sensor) this does NOT require any special tools, just disconnect the NEG battery cable for about 15 secs.

When remeoving the electrical connection from the sensor, TRY using your fingers FIRST (a little contortionary talent helps) use pliers as a "last choice"

DO THIS ONLY ON A COLD ENGINE!

[edlee]

You should not need to disconnect anything extra if you disconnect and remove your car battery. Removing the car battery makes it easier to access the engine coolant temperature sensor as well. I use a socket wrench with an extension to reach the bolt that holds down the battery closest to the engine.

[Grandpa Joe]

Hi all,

This is my first time posting here and am looking for help with my father's '98 SL1. Immediately after we start the car the temp guage goes to the halfway mark. The car sometimes sputters and dies, but will usually restart after a short wait. I picked up an Actron OBDII code reader when they were on clearance at Kragen Auto Parts for $19. Great deal. The only code it shows is P0117. I replaced the ECTS and the thermostat and that hasn't solved the problem. Is there anything else I can check related to code P0117 that could be causing the problem?

A few things to note: I did not (yet) replace the pigtail connector for the ECTS. We mistakenly did not disconnect the battery terminal before doing the procedure. How important is this, and would it help to do it now? Also, when replacing the ECTS, I learned that my father had been using only water and no coolant in the system. He did this because he said it was using water too quickly (not leaking) and didn't want to keep loosing costly fluid. Where could the water be going, and could this lack of coolant in the system be affecting the sensor and possibly triggering the P0117 code?


I appreciate all the help anyone could give.

Thanks in advance,
Ken