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203 Thermostat

17K views 53 replies 20 participants last post by  ArcticDriver 
#1 ·
I need to change the thermostat. Since I bought the truck it hasen't seemed to stay at operating temp. And now winter, I don't get alot of heat from the heater unless I'm working the truck. Carqueast only lists a 195 thermostat. Where's the best place to buy a 203? BTW its for the 96 is my sig.
 
#2 ·
#4 ·
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Your to cool due to the existing thermo is in bypass mode

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What's that mean??? Please explain, because i'm in a similar situation. Thanks.

Joe
 
#5 ·
In the event of thermo failure. It will go into a bypass so not to overheat motor. The oem thermo has a rubber ring around the outside diameter of the thermo that tares from the thermo exposing holes in the thermo causing coolant to bypass the thermo.

way to many thermo's in tread!!!!!!!!!
Was a problem in model year 97.
I have a 97 thats Y I know!!!

Bill
 
#6 ·
I had the same problem.

I went with the 203, and really like it in the winter.
 
#8 ·
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O ya best mod for the $$$ I have done.

Cary

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Really....... got me excited now

Thanks for the link and all the reply's
 
#9 ·
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The oem thermo has a rubber ring around the outside diameter of the thermo that tares from the thermo exposing holes in the thermo causing coolant to bypass the thermo.

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This is not true. There is no such design.
 
#10 ·
There are two lengths of thermostats. I don't remember when they changed them. I almost positive that your 96 has the long one. Your 94 may have the short one. If the water pumps have been changed you could have either one. The only place to get a long 203° long T-stat is from Dieselsite. The different lengths are not interchangable.
 
#11 ·
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There are two lengths of thermostats. I don't remember when they changed them. I almost positive that your 96 has the long one. Your 94 may have the short one. If the water pumps have been changed you could have either one. The only place to get a long 203° long T-stat is from Dieselsite. The different lengths are not interchangable.

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Right.. I think they changed in 95. When I went to the parts house and they listed a short 205* for 94-95 and the long 195* for 96-97.
Thanks, I'll be order one sooon!
 
#13 ·
mad--never seen a thermo like that--wild--
 
#15 ·
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Here is a pict of a oem thermo i pulled out of my 97.
Bill

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Can you provide a Ford part number for that thermostat, I would like to buy one.

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444-4D
Here you go.
Thermo is made by Behr-Thomson in Germany. Part #S on Stat
97
2.153.89
1822815C1
The 1822815C1 i believe was the Part# International used.
This came out of a virgin Powerstroke!!!
This was the OEM stat in 97!!!
BTW--94.5 to 95 short stat. 97 long stat. Somewhere in 96 was changeover.

Good Luck--Believe what U want.
For your reading pleasure
http://www.thedieselstop.com/archives/ub...amp;fpart=1.htm

Bill
 
#17 ·
Those numbers are the correct ones for the standard Ford thermostat. There is a ring around the center valve that appears to be rubber. I think it is simply a seal and the holes are there to aid in the bonding of the rubber to the metal. It is possible that it could be some type of plastic that melts away at high temps and allows coolant to flow thru those little holes and around the outside of the valve but it appears to simply be a rubber seal. It could also degrade with age just like a hose and come loose. If it came loose some coolant would go thru the thermostat(not bypass it)and cause slower warmup.
 
#18 ·
If the coolant goes thru the stat its being bypassed. It bypasses enough that the motor will not overheat (failsafe mode). In the winter time if bypassing you have crappy cab heat.

99% of the time most donot know of a problem with the stat due to all is fine.

All complaints start from crap heat in cab.
All due to bypassing stat in winter, causing overcooling.

I'am done
 
#21 ·
Make sure you have enough anti-freeze in the fill resevoir. I had a minor leak around my heater pipe above my water pump and it eventually drained down enough not to allow heat to the cab unless I kept the RPMs up. Bad bad owner! I even bought a thermostat thinking that was it (never have had to replace it since new). I really hate to say this, but when I popped the hood to check for leaks, my girlfriend immediately pointed out the low resevoir level. Gotta keep that girl around! (give credit where credit is due).

Later
 
#22 ·
I like the idea of that stat. Not sure how it works in practice
 
#23 ·
The stat can stick open too and the engine will not heat up well either.
I had this happen in a couple vehicles too.

Not really sure the 203 stat is really worth the money. How much difference is 8 degrees F going to make?

Answer very little if both T-stats are in good working order.

My opinion is get a good stat from IH, Ford or Napa and run with it.

Tim
 
#25 ·
I know for sure the 203 is very different then the 195.

The temp gauge will move from (n) to the middle of (or)on it.

Heat from the heater will be better.

Summer use will not be affected.
 
#26 ·
You can use the 203 all year round. If you are now not getting to opt temp it would most likly be your thermo. From my findings the guy's that have seen gains (mpg) with the 203 stat was because the one that they replaced was bypassing and did not know it was. The benefit of the 203 might give the motor a longer life. (the hotter u can run a motor the less it will ware) I have had motors that did not need the cooling fan in 90deg temps due to the bypassing stat. The stroke does not waste alot of energy converting it into heat unless you work it hard.
I had one stroke that had good cab heat but if i put the heater fan on high in a few minutes it would blow cold and motor temp would start to fall. All due to the stat.

Bill
 
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