I have a 1992 Ford Thunderbird and have taken care of it since I have
purchased it new in 92. After a couple of years I learned of the Head
Problems that can happen with these engines. One of the reasons is
design and the radiator sets lower than some of the cooling in the
heads in the engine.
I tried to take care of this car and just recently blew the heads and
emptied the radiator thru the exhaust as I was traveling on the highway
after 216,000 miles on original heads..
Here is what I know after owning this car for 13 years.
1. When checking the coolant level check the overflow level in the
overflow bottle. Do not remove radiator cap for a coolant level check
as air most likely will enter the system as the Radiator fill is below
the water level in the heads. Can also check top radiator hose by
touching it carefully as to see if it is hot if engine is just started
it will take a few minutes for the hose to get warm and the bottom of
the hose will heat up first as flow will be slow at first and that
means coolant is should be flowing thru the system. The radiator cap
is below some of the head cooling and this coolant in the heads will
drop down to the level of the radiator fill cap as it spills out the
fill cap opening..
2. If radiator cap is removed then the vent on top of the engine most
likey will have to be removed and the radiator topped off. To do this
I have found if the front of the car is elevated compared to the rear
(I can tell if the front of the car is at the correct height as the
vent water level will be the same as the Radiator fill Cap opening) I
can top off the radiator till I see the fluid in the vent. There will
be some bubbling as the air is purged with the water moving in to the
voids. If you have the proper Thermostat with a small check valve or
bleed valve and it is located at the top of theThermostat in the
housing then the next time the engine is run the radiator may sippon
fluid from the resorvor to the radiator. And the vent can be loosened
and vented. This does not always get the air pockets out from my
experience as afterward when driving the thermostat will cycle and the
temp gauge will go from 1/4 up to half way up with spikes higher to
near too hot.
3 Get the correct thermostat and that can be hard at times and I have
a hard time to get a mechanic to listen to me to install the correct
thermostat.. The correct Thermostat has a little bleed or some call a
check valve and this is important in removing any airt or steam pockets
in the heads. The Thermostat is mounted with the air bleed or check
valve at the 12 o clock position), I just had my heads worked on and I
asked for the Thermostat with the vent in it and they put a stat in
with out the bleed I knew almost right away it was wrong or they did
not vent the cooling system correct. I also had asked for Prestone the
Yellow Anti Freeze that will mix with any anti freeze and they put in
the green stuff they get in 55 gallon drums for little nothing. I also
knew I had a air lock or vapor lock in the heads as when I filled up my
gas I only got 16 miles to a gallon and so I knew the water at the
sensor was too cool and I was not getting correct circulation, The
temp sensor kept the car computer in closed loop and that made the gas
milage bad. Steam or vapor or air lock will prevent correct circulation
and cause cool spots or even worse hot very hot areas on the heads that
can warp or crack the heads or blow the head gaskets.
An early sign that something is wrong is the heat output of the heater
just won't be as hot it will seem like the car will never quite get
warm enough this can be the begining or the head or heads going bad.
If heat output is down get a pressure test before the problem gets
worse and may cost even more money.
This is what I have found to work for me on my 3.8 Thunderbird. With a
little care they will last and a understanding of the cooling of the
I post this as someone may search for this problem and this may be of a
help to them.