The Easy Way to Change Your Cylinder Head Temperature Sensor(chts)
The manual says to remove the timing belt and the backing plate to do
this, but here is the easy way:
- First, locate the sensor, it is on the front face of the driver side head.
Hard to see sometimes, look around.
- Remove spark plug wires from distributor cap and disconnect temp.
sensor(this takes some time and frustration the first time)
Also remove the engine driven fan. You need to loosen the
tension on the alternator/water pump belt before you
do this. Remove the 4 small bolts that hold the fan clutch
onto the water pump and it slides right off with a little
wiggling to free it.
- Take a really long straight edge screw driver, and stick it down into the
engine from up top beside the distributor cap. You should be able to see
the temperature sensor from this spot. Rest the screw driver on the temp sensor.
- Now the fun part: Get a big hammer and break off the plastic connector
on the temp sensor. Carefull, it is fairly fragile, a small hammer will
probably do also, but is not as much fun.
- A shallow socket will now fit over the temp sensor, with the back edge
of the socket actually behind the timing belt cover. use the socket only to
break the sensor loose, because if you screw the sensor all the way out, it
will jam and the sensor and socket will be stuck behind the timing belt
back plate, if this happens, simply screw the sensor back in until the socket
can be removed. You can screw it the rest of the
way out with your fingers, if it is dirty and difficult, use a pair of
pliers, remember, you're throwing this part away.
Once out, blow the hole out with air.
- The new sensor can be screwed firmly down with your finger tips, I usually
put a layer or two of teflon tape around the threads to seal them, and it
will be much easier to remove if you have to do it again. Do not put tape over the
tip, which is where the sensor contacts the head.
- Now the tricky part: A deep well, 12 pt socket larger than the actual
fitting on the sensor will fit cocked over the whole sensor, and will
grip just tight enough to tighten the sensor down.
- Before you plug the sensor back in, remove the "sub harness" and
inspect it. This is the short two conductor wire that goes from
the temperature sensor and plugs into the engine harness by the
front passenger side spark plug. Look just inside the connectors
at the wires, they have a habit of breaking right here. If they
are cracked/broken/whatever, make or buy a new "sub harness".
You can cut the appropriate connectors for one off a wrecked car,
the temperature sensor uses a standard injector connector and the
other end, well, you can look around and find another one under the
hood of a wreck. Wire them together and off you go. The sensor
is a thermisistor, so the polarity of the wires doesn't matter.
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