carbide@egine.com

I just took my new-to-me '94 Explorer on its first backroad trip. It
did GREAT! Gravel roads, fording a foot-deep stream, a steep, muddy,
rutted road- it handled it all. This is just what I wanted.

However, I noticed that on long downhills the temp indicator dropped to
cold. I had noticed that the temperature gauge normally read low, the
needle right at the line between "cold" and "normal" but figured that
could be typical.

I've seen this on other vehicles, and wanted to get it fixed before it
gets cold and I need the defroster/heater.

I figured it was stuck open, but when I got it out (good thing I had a
wobbly adapter and various extensions!) I found it closed.

So I put it in a pan with the new thermostat, fired up the burner, and
watched. The old thermostat opened sooner than the new one, and once
they were opened, I turned off the heat and started adding cold water
to the pan. The new thermostat promptly closed, but not the old one. I
removed them from the pan and the old one was still open slightly,
though it was cool enough to touch the brass part that contains the wax
pellet.

I don't know what goes wrong- if the spring weakens or what, but the
new thermostat works great. There's only two needle widths difference
on the temp gauge between going up a long hill and going down it, and
it reads well into the normal range instead of at the bottom end.
-Paul

Rob Burtz

I've been through two thermostats in my '94 XLT and need to put another one
in. I don't know why they keep "Sticking Open" but it seems to be a common
occurance.

Rob

<carbide@egine.com> wrote in message
news:1130630260.041553.222190@g44g2000cwa.googlegroups.com...
>I just took my new-to-me '94 Explorer on its first backroad trip. It
> did GREAT! Gravel roads, fording a foot-deep stream, a steep, muddy,
> rutted road- it handled it all. This is just what I wanted.
>
> However, I noticed that on long downhills the temp indicator dropped to
> cold. I had noticed that the temperature gauge normally read low, the
> needle right at the line between "cold" and "normal" but figured that
> could be typical.
>
> I've seen this on other vehicles, and wanted to get it fixed before it
> gets cold and I need the defroster/heater.
>
> I figured it was stuck open, but when I got it out (good thing I had a
> wobbly adapter and various extensions!) I found it closed.
>
> So I put it in a pan with the new thermostat, fired up the burner, and
> watched. The old thermostat opened sooner than the new one, and once
> they were opened, I turned off the heat and started adding cold water
> to the pan. The new thermostat promptly closed, but not the old one. I
> removed them from the pan and the old one was still open slightly,
> though it was cool enough to touch the brass part that contains the wax
> pellet.
>
> I don't know what goes wrong- if the spring weakens or what, but the
> new thermostat works great. There's only two needle widths difference
> on the temp gauge between going up a long hill and going down it, and
> it reads well into the normal range instead of at the bottom end.
> -Paul
>

Mike Iglesias

In article <XcOdnVUsuKlr3PneRVn-qg@comcast.com>,
Rob Burtz <rburtz515@comcast.net> wrote:
>I've been through two thermostats in my '94 XLT and need to put another one
>in. I don't know why they keep "Sticking Open" but it seems to be a common
>occurance.

Think about what would happen if it stuck shut...


--
Mike Iglesias Email: iglesias@draco.acs.uci.edu
University of California, Irvine phone: 949-824-6926
Network & Academic Computing Services FAX: 949-824-2069

carbide@egine.com

Mike Iglesias wrote:
> In article <XcOdnVUsuKlr3PneRVn-qg@comcast.com>,
> Rob Burtz <rburtz515@comcast.net> wrote:
> >I've been through two thermostats in my '94 XLT and need to put another one
> >in. I don't know why they keep "Sticking Open" but it seems to be a common
> >occurance.
>
> Think about what would happen if it stuck shut...
>

I've heard of it happening, but of the 5 thermostats I can remember
replacing over the years, it was always for running too cold. The
opening force provided by the thermal expansion of that wax pellet is
pretty irresistable.

Of course they make the body of stainless steel now. I think they used
to be brass in the olden days, that could corrode and break...

BTW, I think my old thermostat might have been the original, with 164K
on it. I don't see any mention of a thermostat change in the records
the previous owner gave me.
-Paul

xcaret

Well heres what my 94 explore did ( and a friends also ) . Regardless
of the outside temperature the gauge always said it ran real cold
,used lots of gas too. My friend said to remove the heat sensor that is
just tucked in frt of the a/c compessor on 4 L engines and clean it ,I
did and now run at normal temperatures .Get much better gas milage too
.. The sensor tells the computer the engine is still cold and computer
tells the choke to stay on and the guage to register cold ..This is
rather common on early Explorers.

xcaret

Well heres what my 94 explore did ( and a friends also ) . Regardless
of the outside temperature the gauge always said it ran real cold
,used lots of gas too. My friend said to remove the heat sensor that is
just tucked in frt of the a/c compessor on 4 L engines and clean it ,I
did and now run at normal temperatures .Get much better gas milage too
.. The sensor tells the computer the engine is still cold and computer
tells the choke to stay on and the guage to register cold ..This is
rather common on early Explorers.

Happy Traveler

Your '94 Explorer has a choke?????
In 1989 I purchased a five year old LTD, with throttle-body injected V6. A
bit of black smoke was visible in the exhaust and I pointed it out to the
salesman. "It's the choke sticking a bit", he said. "A choke, on a fuel
injected engine?", I wondered, knowing next to nothing about fuel injected
engines. "Yes, they still have them", he replied with great confidence (it
turned out to be the infamous carbon clogging of the EGR valve). I still
have the vehicle. Haven't found the choke yet, but I keep trying.


"xcaret" <xrt11@hotmail.com> wrote in message
news:1130697005.381669.173830@f14g2000cwb.googlegroups.com...
....
> The sensor tells the computer the engine is still cold and computer
> tells the choke to stay on and the guage to register cold ..This is
> rather common on early Explorers.
>

carbide@egine.com

xcaret wrote:
> Well heres what my 94 explore did ( and a friends also ) . Regardless
> of the outside temperature the gauge always said it ran real cold
> ,used lots of gas too. My friend said to remove the heat sensor that is
> just tucked in frt of the a/c compessor on 4 L engines and clean it ,I
> did and now run at normal temperatures .Get much better gas milage too
> . The sensor tells the computer the engine is still cold and computer
> tells the choke to stay on and the guage to register cold ..This is
> rather common on early Explorers.

Mine has two sensors, right behind the thermostat. The one on the left
is for the gauge, the right one tells the fuel injection the coolant
temperature- according to my Haynes manual.

It does say that the fuel injection "runs open loop" when cold, i.e. it
doesn't use the oxygen sensor to fine-tune the mixture, which will
cause poor fuel economy.
-Paul

Ulysses

<carbide@egine.com> wrote in message
news:1130630260.041553.222190@g44g2000cwa.googlegroups.com...
> I just took my new-to-me '94 Explorer on its first backroad trip. It
> did GREAT! Gravel roads, fording a foot-deep stream, a steep, muddy,
> rutted road- it handled it all. This is just what I wanted.
>
> However, I noticed that on long downhills the temp indicator dropped to
> cold. I had noticed that the temperature gauge normally read low, the
> needle right at the line between "cold" and "normal" but figured that
> could be typical.
>
> I've seen this on other vehicles, and wanted to get it fixed before it
> gets cold and I need the defroster/heater.
>
> I figured it was stuck open, but when I got it out (good thing I had a
> wobbly adapter and various extensions!) I found it closed.
>
> So I put it in a pan with the new thermostat, fired up the burner, and
> watched. The old thermostat opened sooner than the new one, and once
> they were opened, I turned off the heat and started adding cold water
> to the pan. The new thermostat promptly closed, but not the old one. I
> removed them from the pan and the old one was still open slightly,
> though it was cool enough to touch the brass part that contains the wax
> pellet.
>
> I don't know what goes wrong- if the spring weakens or what, but the
> new thermostat works great. There's only two needle widths difference
> on the temp gauge between going up a long hill and going down it, and
> it reads well into the normal range instead of at the bottom end.
> -Paul
>

The temp gauge on my '92 was reading low so I took out the thermostat, put
it in a pan along with a new one, and the new one opened sooner (around 185
degrees) so I put the old one back in and put the new one on the shelf. It
still reads a little on the low side but better than overheating ;-)

The old Explorers go through a lot of thermostats and it doesn't seem to
matter what brand it is.

Ulysses

Good tip. I'm gonna try that.

"xcaret" <xrt11@hotmail.com> wrote in message
news:1130696962.923849.123170@g43g2000cwa.googlegroups.com...
> Well heres what my 94 explore did ( and a friends also ) . Regardless
> of the outside temperature the gauge always said it ran real cold
> ,used lots of gas too. My friend said to remove the heat sensor that is
> just tucked in frt of the a/c compessor on 4 L engines and clean it ,I
> did and now run at normal temperatures .Get much better gas milage too
> . The sensor tells the computer the engine is still cold and computer
> tells the choke to stay on and the guage to register cold ..This is
> rather common on early Explorers.
>