Contour Enthusiasts Group Archives Forums Modifications Zetec Maintenance thermostat replacement

It's so easy, I've done it on a break at work (and I work in an office and need to be clean).

haynes manual says I need to drain the coolant first, is this true?

done. lost more coolant than I thought I would but it's cool because I got to add just water and that helped to changed my old 50/50 ratio to something better. driveway smells like fish now. i recommend this for EVERYONE that owns a zetec to do. it's simple, quick, and easy to do. All you need is a flat head screwdriver, 8mm socket, extension, ratchet, lower temp thermostat (~$15), gasket ($3), and water. It ran on 'O' the whole way home tonite, usually it would be around the 'M' and sometimes higher.

one question though: this thermostat has no air bleed valve like stock. does that matter?

another observation: tonight, temp. in 80Fs.
on drive home from work, i had defroster on because of rain.
the whole way home the temp gauge sat right at bottom of the 'N' and as I came into my driveway, it was barely sitting in the NORMAL operating range area. it really helps a lot.

drill a small hole in it.

hm...

#1 If the temp is too low, the PCM will think the car
is in warmup mode and will rich the mixture all the time.
I had this when my temp. sensor went bad. Car ran like a
champ with MPG below 20... Not something healthy.

#2 I was told the hotter an engine is (i.e below warpage/
fluid boil limits of course) the more efficient it is,
that's why we don't run our engines at room temperature.
What's the truth about it ?

T.

1.it's still in normal range
2.untrue, that's why we want colder air and that's why nitrous is used