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Old Sep 29, 2007 | 05:53 AM
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Thermostat Nightmare

So my truck broke down an hour from an auto parts store turn out the water pump seized. So i got my list together and went down to carquest and gota new pump and thermostat and gaskets and serpentine belt. I got back to the truck installed the water pump and attempted to install the thermostat. Turns out the gasket they gave me went around the thermostat (rubber o ring) and once installed on the thermostat didn't fit in the groove in the water pump. So i went back down to carquest and they swore it was the right part. Next stop auto zone. (not my favorite choice) they gave me an o ring and a thermostat but this time the oring just goes on top of the thermostat back i went to the truck installed it and IT LEAKED!!!! out it came. Off to the Stealership fed up and really mad. they said well it has thhe thermostat with gasket installed and this o ring that goes on top.
The o ring they handed me looked just like the one from auto zone but the thermostat had a gasket already installed and the outside diameter was the same as the carquest one without the gasket installed. So i they said how does this gasket on the thermostat fit in the small space withthis o ring on top? Parts guy told me not sure but that what the book says has to be installed. So after this arguement we went to the diesel mechanic at the dealer and he said oh the book is wrong and this is an updated thermostat and the additional gasket is no longer used. GRRRRRRRRRRR
So i bought the thermostat 46.00 holy **it! I asked if they knew it was only a thermostat? but they insisted well its a diesel!!!! So 200 miles later i have a really expensive thermostat and reassurance that the dealer is out to ROB ME!!!! But i no longer have any leaks.
 
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Old Sep 29, 2007 | 06:01 AM
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there is 2 different thermostats..the ford power stroke diesel takes a different style..if you get the wrong one you can burn the pistons in the back..take yours out and bring it with you..it is all so recommended you change the cheaply built housing too..they will leak after reinstall them...a lot of us use this 203 stat..

http://www.dieselsite.com/index.asp?PageAction=VIEWPROD&ProdID=186

and we use this housing
http://www.dieselsite.com/index.asp?PageAction=VIEWPROD&ProdID=188
 
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Old Sep 29, 2007 | 06:08 AM
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Here's a little background on the Ford Powerstroke thermostat...

Until 1996, all 7.3L Powerstrokes that were manufactured used an International water pump and an International short stem 203<SUP>o</SUP> thermostat . In 1996, Ford changed to a lower degree 195<SUP>o</SUP> thermstostat. They changed water pump designs at this time as well. The new pumps required the new long stem 195<SUP>o</SUP> thermostat in place of the short stem to properly seat the bypass disk. All 1996-2003 Ford PSDs now come equipped with a long stem 195<SUP>o</SUP> thermostat. Recently the factory replacement thermostat available at the parts counter changed to 192<SUP>o</SUP>.
 
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Old Sep 29, 2007 | 08:46 AM
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Like Ron Said, just get a 203 from Dieselsite and then either a new housing, or RTV your existing housing. I had the same problem with leakage when I replaced my thermostat.
 
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Old Oct 4, 2007 | 08:07 PM
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So let me see if i Understand it right. So the one i got at the dealer is BAD? I have no leaks now and thats the one they said i needed ???? i believe its a 195 degree thermostat. Do i need to get it out??
 
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Old Oct 4, 2007 | 08:11 PM
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its a matter of short stem and long stem thermostat..not the degrees..
 
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Old Oct 4, 2007 | 08:20 PM
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I replaced my water pump this last june and still had the short stem t-stat housing and think i got the 195 t-sta. is that bad??? no leaks.
 
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Old Oct 4, 2007 | 10:34 PM
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Originally Posted by ron's power stoke

Here's a little background on the Ford Powerstroke thermostat...

Until 1996, all 7.3L Powerstrokes that were manufactured used an International water pump and an International short stem 203<SUP>o</SUP> thermostat . In 1996, Ford changed to a lower degree 195<SUP>o</SUP> thermstostat. They changed water pump designs at this time as well. The new pumps required the new long stem 195<SUP>o</SUP> thermostat in place of the short stem to properly seat the bypass disk. All 1996-2003 Ford PSDs now come equipped with a long stem 195<SUP>o</SUP> thermostat. Recently the factory replacement thermostat available at the parts counter changed to 192<SUP>o</SUP>.
Good to know.
Any idea on why they dropped the temperature even more?
 
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Old Oct 4, 2007 | 10:41 PM
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Originally Posted by Kwikkordead
Good to know.
Any idea on why they dropped the temperature even more?
no i dont..i got that from dieselsite..here is the rest of it

WHY IS 203<SUP>o </SUP>BETTER THAN 195<SUP>o</SUP>?

Diesels run most efficiently at approximately 200<SUP>o</SUP> or above. A factory equipped 192<SUP>o</SUP>/195<SUP>o </SUP>thermostat will maintain an operating temperature at approximately 165<SUP>o</SUP>-170<SUP>o</SUP>. 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<SUP>o</SUP> thermostat maintains a minimum operating temperature of 190<SUP>o</SUP>. This brings the operating temps up from as low as 170<SUP>o</SUP> to as high as 203<SUP>o </SUP>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.

When our trucks are under load and are producing higher combustion temperatures the 203<SUP>o</SUP> will allow the engine to run even closer to its optimal operating temperature. If the truck is under load and reaches the 203<SUP>o</SUP> 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<SUP>o</SUP> thermostat. The end result of installing the 203<SUP>o</SUP> thermostat should be slightly better fuel economy, less smoke, and maybe a few extra "ponies" to go along with it.

WHY A LONG STEM AND NOT A SHORT STEM?
Although International still uses a 203<SUP>o</SUP> 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.

The 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.

We know 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<SUP>o</SUP> thermostat will not encounter these problems! It's designed to work as the OEM unit did WITH the long stem for bypass protection.

WHY USE THE DIESELSITE 203<SUP>o</SUP> THERMOSTAT?

Higher optimum operating temperatures reached 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 uncontrolled bypass.
 
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Old Oct 4, 2007 | 10:43 PM
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Thanks for that info.
 
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Old Oct 4, 2007 | 10:45 PM
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Originally Posted by Kwikkordead
Thanks for that info.
any time.....all i had to do was copy and past lol
 
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Old Aug 22, 2014 | 05:56 PM
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1988 F250 Diesel Lariat

The gauge on the dash is almost half using a Cen tech infrared thermometer






The temperature at the thermostat housing and neck read between 178 and 183






08/22/2014 F250 Lariat thermo temp



1988 F250 Temp gauge reading


when accelerating at 2000 RPM for few the releasing the throttle the engine quits same scenario when driving and preparing to stop the engine will quit


Video


after letting it idle for 15 minutes it still has not reached temperature above 190 so have ot been able to check if thermostat opens


A new thermostat calls for Part Number: 4399
Weight: 0.2 lbs
Warranty: 1 YR
Application: OE recommended temperature
Notes: 195 degreesSeal included
Gaskets Included: Yes
Material: Stainless Steel, Copper
Package Contents: Thermostat, Gasket
Thermostat Opening Temperature (°F): 195
 
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