Scary, improper engine temperature can ruin an engine. I'd get the heater
problem fixed. I also fail to see how removing the thermostat fixes a
problem with the heater. If for instance your heater coil leaked and you
didn't want to replace it (why?) then you can run a bypass, you don't just
plug the hoses. Anyway, I tend to agree with the headgasket. You can have a
faulty head gasket without any lose in power etc. You blew it off without
even a so much as a by your leave. How did you check the engine to be sure
that a head gasket wasn't the problem? You've replaced the water pump, the
radiator and the hoses. This leave the problem to the engine, most common
cause of the engine causing overheating.
Not enclusive, but the most likely suspect...
Engines can actually overhead if the fuel/oxygen mixture runs too lean.
If it runs lean the engine heats up real bad as does the catalytic
converter. In some cases the catalytic converter gets fried. The heat
on the converter is intense, in some situations the heat can be felt
through the floorboards. Once the converter is damaged, your exhaust
will start smelling like rotten eggs.
A bad O2 sensor can make the mixture run too lean or rich. But don't
simply replace it just yet because those sensors are expensive and can
run upwards of $300 by itself. On some cars there are two o2 sensors.
One on the exhaust manifold and another one underneath on the exhaust
I've heard of PCM powertrain control modules going bad. But I'm not
sure if that would cause this.
Your taurus uses digital technology to get by. Mechanical and digital
Check to find out if there are engine codes. Even if the check engine
light is off, there is a possibility that the dashboard bulb for the
warning light has burned out.
Also check if the coolant sensor(s) are in good shape. Some cars have
two, one for the temp dashboard gauge and another one for the PCM.
Sounds to me like it could be a sensor/computer problem.
Who knows, maybe the engine isn't overheating and it's just the gauge
giving a false reading because of a bad sensor. But I wouldn't risk it
and take the chance of frying an engine.
You're right about the lean mixture but, in computer controlled, fuel injected
this it is almost a non issue except for a plugged fuel filter. If it was a
overheating due to a lean mix it would be about 3rd down on the list of things
check. Yea, it could happen now, but I've never seen it in 20 years. No dis
just relaying what I've seen. Modern FI cars seem to usually overfuel when
We need some basics about your car. What year and what engine? This is
sound like a 3.8 head gasket problem, or a really plugged system from the "Brown
Coolant" concern in later 3.0 cars. Year and engine would help immensely.
Ok, probably not head gaskets. This is good. First, how do you know it is
overheating? When does it overheat? Idle\low speed? Highway speed? You need to
thermostat in there. Lack of one can actually exacerbate an overheating
The "hoses were plugged" and you don't think that is a problem?
The thermostat is in the car for a reason, and that reason is to recalculate
the engine coolant through the engine UNTILL it reaches operating
temperature, at that point it will start to release coolant from the engine
to the radiator, but if you have no thermostat, your engine will never reach
operating temperature because the coolant is already sent to the radiator.
not good for mileage.
I would suggest that you take the car back to stock. Unplug the hoses and
properly install the thermostat - if put in backwards you will have heating
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