Location of Coolant Temp Sensor - 1995 F150 4.9L I6
Mac
engine temperature needle has ALWAYS been in the middle of the
'NORMAL' zone when the truck was warm (ex.... between the 'R' and 'M'
in the word 'NORMAL').
About 4 months ago, I drove all the way to work (about 15 miles) and
the needle never came off 'C' (Cold). There WAS warm air (actually
HOT air) coming out of the ducts though. I tapped around the
thermostat area and (what I think is) the temperatire sensor, and the
needle slowly came off the 'C'. It now sets on the 'N' of the word
'NORMAL' (barely!).... but you can see the needle position fluctuate
ever so slightly when it's warm. It never has made it back to the
center of the normal range since then.
I asked the dealer about this when I took the truck in for some
routine maintenance, and they checked it out (supposedly). They said
everything was working OK... there was hot air coming out of the
heating ducts, so the truck was getting up to temperature. You see,
they never knew where the needle NORMALLY sat when warm.... I (on the
other hand) knew something had changed.
I talked to a buddy down at work who works on race cars, and he said
it sounded like my thermostat was stuck open. I bought a new
thermostat and installed it.... AN EASY JOB! But... no change in the
needle position.
As a side note, I've been getting only about 15 miles per gallon
(mileage), which may or may not be related to this... but it makes me
wonder. I don't remember when the bad mileage thing started. Could
the temperature sensor not be telling the engine that it is up to
temperature... possibly making it run rough? For a small 4.9L I6
engine... 15 miles per gallon seems way too low. I have an 8cyl GMC
that gets 20+.
Anyway, back to my question.... my plan is to change the coolant
temperature sensor next. Looking at the engine from the front, about
4" to the left of the thermostat is an electonic device that appears
to plug into a metal coupler in the heater line. I've already had the
plug off to clean it. There are 2 prongs in the plug. The female
device it plugs into has a hex shaped surface on it... much like a hex
nut. Normally, I'd just put a crescent wrench on it and start
turning.... but I want to make sure that:
1. Is this the coolant temperature sensor? I'm guessing it is.
2. Am I getting the right read on the hex surface? does the unit
simply unscrew, or is this a bayonnette mount? I don't want to put a
wrench on it, start turning, and hear a 'snap'. I'm asking because I
don't see any exposed threads.... usually I'd expect to see at least a
couple.
3. If it does unscrew, I'm assuming you can just buy a new sensor
unit and screw it back in to the coolant line pipe. Does anyone know
about how much a temperature sensor is for a 1995 F150? $20? $50?
$100?
Thanks a lot for the help!!!
Mac
Kevin Mouton
A simple suggestion. Buy a new coolant temperature sensor and look at it
to see if is the same as the one you are about to remove. You will also
see that the new one has threads.
BTW, a faulty engine coolant temperature sensor can cause a decrease in
fuel economy. You can also test the sensor before replacing it on whim.
Post back if you care for tips on how to test it.
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Red Green
Mac
I've already replaced the coolant temp sensor (next to the
thermostat), and I have also replaced the thermostat with a 195 deg
unit. The temp gage still never quite gets to the 'N' in 'NORMAL'.
This would normally be no big deal, except that it usually sets
between the 'R' and 'M'..... nead nuts straight in the middle. All I
know is that something has changed.
I'd like to change the engine temp sensor that feeds the temp gage on
the dash. I just about bought one yesterday.... they're only $6.00 at
Car Quest, so they're pretty cheap. The guy there said he had heard
they were REAL hard to get at on the 4.9L I6 engine. Said you have to
'break your arm in about 3 places' tp get at it. Can you describe to
me just where this sensor is located? Either that, or possibly send
me a picture out of a service manual. I hate to buy an entire manual
just to find out where this thing is on my engine. I've looked the
whole thing over with a flashlight, and can't see anything that
resembles it.
Thanks Kevin.... Mac
Kevin Mouton <kev...@bellsouthgarbage.net> wrote in message news:<3BD8B71B...@bellsouth.net>...
