ECTS = Engine Coolant
If you have a Saturn S-Series
that was made before mid 2001, you should probably replace the ECTS in your car. Before that year, Saturn used a
resin-tipped ECTS, then they switched to a brass-tipped one.
The resin tip will inevitably split, and the sensor will go
bad, and may even allow some small amounts of coolant
leakage, causing corrosion on the wiring harness for the
ECTS. For a $10-20 part, and to avoid all the problems
that come with a bad ECTS, it is worth replacing, and it's
You have two temperature sensors in the area. The
two-wire one is the ECTS that sends to the PCM. The
other sends to your instrument cluster.
The ECTS is a thermistor - that
is, it's a resistor that changes resistance with
temperature. The resistance level tells the PCM the
coolant temperature. The ECTS and the IAT (Intake Air
Temperature) are the same part.
This is a good thing to do while
you're at it if you need to replace your thermostat, or
anything else that drains the coolant. You do not,
however, need to drain the coolant to replace the ECTS.
<< sensor end wiring connector end >>
8mm, 13mm sockets & ratchet
Needle nose pliers
(angled tip if you have them)
Rag (don't worry, you
won't have to use it much at all if you follow
New ECTS (brass-tipped.
You can get this at the dealer, or a parts store.
Some parts stores still have the resin-tipped ECTS, so
look before you
New ECTS wiring connector
(Optional) Sometimes a bad ECTS allows coolant onto
the connector, causing corrosion. If this happens,
you need a new connector. If not, you probably
don't. If a place stocks one near your house,
might wait. If it's going to be a show stopper and
keep you from getting to work, you might go ahead & get
it, and either replace it whether or not it needs it, or
return the part if you don't need it.
Let the car sit
until the engine is COLD. Not cool, cold.
Overnight cold. If it's warmed up at all, you will
lose a lot more coolant.
negative battery cable.
1. Jack up the driver's side
of the car. This will help reduce coolant loss.
2. Remove the battery.
You have to remove the negative battery cable anyway, and
this will give you extra working space. Requires the
stock intake system (Airbox Lid - Throttlebody)
2. Remove the coolant
reservoir cap, then put it back on. This relieves
pressure on the coolant system so when you pull the ECTS,
the pressure doesn't push more coolant out. Putting
the cap back on helps hold the coolant in.
3. Remove the wiring
connector from the ECTS. If you have needle-nose
pliers with an angled tip, those work really well, but any
needle nose pliers will work, or possibly even your hands.
Squeeze on the two sides to release the connector. The
connector locks in place, so don't pull on the wires - it
will only hurt things.
4. Inspect the wiring
harness. If it has any corrosion, replace it.
5. Remove the ECTS.
Use the 13mm socket, and rotate counter-clockwise (normal
thread). A little bit of coolant will come out (not
even a spoon-full when I did it). Have a rag and the
new sensor ready.
6. Quickly but carefully, put
the new sensor in. Don't over tighten, it doesn't take a
lot of force. (I'll try to find the torque standard
for it and add it here.)
7. Reassemble. Snap
the wiring connector back on the ECTS, put back on
everything else. You're done!