a little background on the Ford Powerstroke thermostat.
is the temperature that navistar designed your truck to
run at. This is the thermostat that was and still should
be in every powerstroke 7.3L.
1996, all 7.3L Powerstrokes that were manufactured used
an International water pump and an International short stem
203° thermostat . In 1996, Ford changed to a lower degree
195° thermostat. They changed water pump designs at
this time as well. The new pumps required the new long stem
195° thermostat in place of the short stem to properly
seat the bypass disk. All 1996-2003 Ford PSD's now come
equipped with a long stem 195° thermostat. Recently
the factory replacement thermostat available at the parts
counter changed to 192°. Our Dieselsite 203° uses
the correctly sized t-stat with the correct temperature
spring so that we no longer have to give up the benefits
of running our vehicles where they were meant to run.
IS 203° BETTER THAN 195°?
run most efficiently at approximately 200° or above.
A factory equipped 192°/195° thermostat will maintain
an operating temperature at approximately 165°-170°.
The Powerstroke has such an efficient cooling system, that
this low flow when the thermostat is slightly open is normally
enough to keep the engine cool. The downfall to this is
that the engine -- when our trucks are not under load --
never begins to reach its optimal operating temperature.
Our 203° thermostat maintains a minimum operating temperature
of 190°. This brings the operating temps up from as
low as 170° to as high as 203° depending on the
operating conditions of the truck. This is closer to the
operating temperature range that is preferable in our trucks
for optimal efficiency.
our trucks are under load and are producing higher combustion
temperatures the 203° will allow the engine to run even
closer to its optimal operating temperature. If the truck
is under load and reaches the 203° setting, the thermostat
is then fully open. This means you are at the maximum coolant
temperature that the truck will reach. Your maximum temperatures
are only a few degrees higher than in stock configuration,
but these are degrees that you want for better performance.
The best benefits come when the same truck is under a light
load and would have a hard time reaching this optimal temperature.
As stated above, you will never reach this optimum temperature
with the stock 195° thermostat. The end result of installing
the 203° thermostat should be slightly better fuel economy,
less smoke, and maybe a few extra "ponies" to
go along with it.
A LONG STEM AND NOT A SHORT STEM?
International still uses a 203° thermostat in some applications
and that thermostat is available at most auto parts stores,
it is the wrong part for the 1996 - 2003 Powerstroke. DO
NOT USE THIS! It has a shorter shaft and will not shut off
the internal pump bypass. This will cause inaccurate coolant
flow direction through the engine. This IH version thermostat
mentioned is available by calling us.
thermostat in the Powerstroke not only controls operating
temperatures, but properly directs the flow of coolant through
the engine. As the thermostat opens, it proportionally closes
the bypass. With the thermostat fully open, the bypass is
mostly closed, and vice versa. With the International (Pre-96
Ford) thermostat, this cannot be controlled properly because
of the shorter bypass stem. The shorter stem of the IH(pre-96
Ford) thermostat allows the thermostat to be fully open
while the bypass is fully open. This means the coolant can
travel in any direction available -- whatever direction
it chooses. It can either travel through the radiator or
simply make the shorter, less restrictive path back through
the front of the engine. This will cause uncontrolled overheating
in the back cylinders of the block, with absolutely no signs
of danger showing on the water temperature gauge in the
cab. It is possible that the back of the engine can have
no coolant flow at all yet the thermometer in the outlet
of the water pump shows all to be normal. Multiple things
can happen at this point. Cylinders can seize, freeze plugs
can fall out and other normal symptoms of an overheating
engine may occur. Worst case is a blown motor and it won't
be covered under warranty.
the warranty departments and engineers at Ford have verified
engine loss due to the short stem thermostats in previous
cases where people were sticking into their trucks to increase
their operating temperatures. As soon as they see the short
shaft thermostat -it's your problem. Our 203° thermostat
will not encounter these problems! It's designed to work
as the OEM unit did WITH the long stem for bypass protection.
USE THE DIESELSITE 203° THERMOSTAT?
you reach a higher optimum operating temperature - safely
- by using our thermostat with the long stem for bypass
protection. It's that simple. We've combined the two units
to bring you a safe alternative. Now you can have the optimal
operating temperatures without risking the chance of uncontrolled
overheating in the back cylinders of the block due to an