2.5L Coolant Temp Sensor Replacement

I have to replace the coolant temp sensor on my 2.5L engine. I may be
an idiot for asking, but do I have to bleed the cooling system after I
take out this old sensor, or can I just plug in the new one with no
adverse affects (assuming that the sensor was the only problem)?

Thanks,

Joe

 

There was no mention of what model you have your 2.5 in. On the
Spirit/Acclaim, the radiator sits lower than the thermostat housing, so
it is a good idea to bleed the system anytime it is opened, other than
the radiator cap. There is a bleeder plug on the thermostat housing for
this purpose.

-Kirk Matheson

 

with kma on this one, bleed the system after replace. The therm.
housing traps air and has to be bled anytime the system is
de-pressurized, sigh.

 

I have a 1988 Aries.....

I guess I'll have to wait to get home to do the procedure.

Thanks,

Joe

 

If ya have a bleed plug on the therm. housing, you'll see it. It a
simple deal, run the engine to ooperating temp., loosen the bleed valve
to let the air escape until only coolant runs out of it.

1] Try to open the valve before any engine run, make sure it hasn't
frozen up.
2] Be careful not to open it up too much, too much coolant may spray
onto the serpentine belt, not a good thing. Also, ya may get some
steam coming out, so watch your hands.
3] Keep eye on coolant level in reservoir tank.

Hope this helps. I surfed autozone's site for your model, no listing
of a bleeder valve in the therm. housing, but if it there, it easy to
spot.

 

--

Ummmmm.. technically you can use the coolant sensor as the bleeder, let the
engine warm up and leave the sensor loose, it is just about the same height
as the bleeder and works just the same.....

Glenn Beasley
Chrysler Tech

 

Now, looking at the thermostat housing, there are two allen wrench
fittings: one on top of the housing, and one on the side near the
coolant sensor. Which one of these would I use to bleed the system
once I get the new sensor in?

 

--

use the sensor that you just replaced to bleed the system

 

I've never done anything like this, so forgive me for sounding
dumb...but do I replace the sensor with the engine cold, and leave the
new one loose, and THEN start up the engine and allow it to warm up?
Won't there be antifreeze everywhere?

 

--

if you do it cold, leave the radiator cap on while you remove and install
the new one, if your afraid to loose coolant, drain some of it down!!

Glenn Beasley
Chrysler Tech

 

It depends. If your antifreeze is properly mixed then it takes a lot
of heat for it to start boiling in an unpressurized system. By then the
major air bubbles will have worked their way to the bleed hole
and you will have poured in more antifreeze into the sensor hole
to displace the air, and screwed in the sensor. It takes time for
heat to work it's way into the coolant from the cylinder walls.

Once the water jacket gets hot enough for the antifreeze to boil
in an unprsssurized system, then when that happens, yes a lot of
antifreeze will want to come out of the hole.

You should have at least 5 minutes of time before this starts
happening.

Ted