Whats does the coolant temp. sensor do?And wht is the difference between this sensor and temp switch for gauge. Mine 3.0 never gets warm by the gauge only slightly so heater never gets very hot. Checked thermostat it works fine. Flushed system several times. Just wondering what the coolant temp sensor does. thanks terry

 

http://fordfuelinjection.com/?p=10

 

I have the exact same problem with my '95.
I haven't found a solution yet, other than a winter front on the Radiator.

 

Both the Engine Coolant Temperature sensor (ECT) and the Engine Temperature Gauge Sensor are thermistors - temperature sensitive devices that change resistance with changes in temperature. The ECT is especially important as it sends temperature information to the computer "brain" (powertrain control module) which in turn uses that information to regulate how rich or lean the engine runs. Obviously, if the ECT is not functioning, the "brain" thinks the engine is always cold and thus keeps things in a rich state, wasting fuel. These sensors do slowly go bad over the years. There are charts whereby you can test their functionality based on ambient temperature and resulting resistance readouts, but I find greater ease of mind just to change it out if in doubt.

Those of you with low reading dashboard temperature gauges, suffer from essential the same problem, a poorly functioning sensor. These sensors have a single wire rather than the two wire, larger ECT sensor - and best of all they are dirt cheap, often going for around $5-6 at most parts stores. I drove around for several years thinking I had a really efficient cooling system as it never registered above "N". I had lots of heat but always a low reading. One day, it dawned on me the sensor might be the problem - it was. Now it reads dead mid range where its supposed to be.

 

Strangely enough, I've changed both of these sensors and my gauge still reads very low. It does "sometimes" reach mid-range, but only if I have been driving for an hour or 2. And oddly enough, even with a winter front on the vehicle, the gauge very quickly drops when driving?? All the way to "C" usually.

 

This is indeed unusual. . . as my 94 3.0 is doing the same thing. Heat never gets above lukewarm, temp gauge never moves up, but it isn't burning rich and no CEL. I drove it home from work, then 5 miles to grocery stors, and even the water pump wasn't too hot to touch. The heater in this van used to run me out even in the snow. I, too, have flushed system, replaced sensors, and new thermostat.

 

Two questions

1) What temp thermostat went in your engine ? correct is 195 *F.
2) Is your fan clutch working properly? this might slightly affect the engines running temp.
The thermostat could have more wide ranging effects though!

Heat (or lack of) inside the vehicle doesn't really prove anything about the engine temp. It just proves that the hot air/water flow is not getting either to the heater core or down the ducting into the vehicle.

Regards Aeroman.

 

heater efficiency in an Aero relies on

correct thermostat 195d F and correct pressure good sealing radiator cap

full coolant level, no air in system

tight seal of the heater core to mount, the foam degrades and falls apart over time

tight seal of the temp door

water flow thru the heater core, the fine core tubes plug over time and scale builts up reducing flow even though the core may be scorching hot to touch

water pump efficiency since the pump pulls coolant thru the heater core instead of pushing, slipping drive belt on pump which is common with no squeal, damaged water pump impeller-some are plastic and break from heat stress over time

hoses breaking down internally where most of the damage occurs, swelling and impeding coolant flow

too high of a concentration of antifreeze in system, more than recommended 50%, slows flow of coolant thru small core openings

 

All these things going on seem to be most of my problems. Low heater output,low temp. gauge reading.I took out thermostat to check it out. It was fully closed as shoul be when cold. I placed in boiling water it opened a little over 1/8 of an inch.If not opening all the the the engine should run hot but it doesn't.I am going to put in another thermostat and temp switch today and also flush system once again and get back with results. It also takes about 15 minutes for engine to get hot enough for thermostat to open this seems to long . terry

 

replace O ring seal on thermostat each time
the O ring breaks down and leaks by defeating thermostat

make sure the thermostat wiggle pin hole is up

take an infrared temp gauge reading on steel pipe out of thermostat housing when engine hot. should be above 150d F minimum

the dash idiot gauge is worthless except to warn of a sudden overheating when the needle pegs on the right side

takes a long time to warm the box interior of an Aero even with both heaters. was 28d F here today, took at least a 1/2 hr before I was comfortable

 

Thats interesting 96_4wdr. The 0 ring you mentioned not sure about the only thing I think of is the gasket.And the wiggle pin hole not sure either would you help me out here . thanks terry

 

maybe there isn't an O ring on the 3L? 4L does have an O ring that goes around the outside of the flat metal plate and seals to housing hole.

not an Aero but the quickest i could grab
pin at top left in plate

 

Thanks for the pictures.I dont think 3.0 does have o ring. The little pin at the top dont think it has that either. The only thing manual says is to place thermostat housing bridge perpindicular to mounting holes. Yep I think or am sure 4.0 thermostat mounts on the front of engine and 3.0 mounts top of engine. thanks

 

A quick check for heater core plugging is to run engine to normal temperature, let idle, and then grasp each line leading into and away from the heater core. Both should be equally hot if the core is open. One line cooler than the other indicates a blockage.

 

My rear heater coil not working for sure one line hot one cold.I tried blowing core out by loosening both lines from underneath didnt work. Now I forget which line goes where. Anyone know which f the two lines under van hooks to the coolant vacuum. I think the line out of core goes into vacuum regulator and line that would be hot goes into core directly. thanks terry