203* thermostat install or not?
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Senior User
Joined: Aug 2009
Posts: 203
Likes: 0
From: Ketchum Idaho
Thanks for your input, Layson! I was just looking at an old thread about this subject and have been getting more educated about this. this forum is great! I'll definately take your advice into consideration.
Posting Guru
Joined: Apr 2009
Posts: 2,447
Likes: 1
From: Northern Idaho
I have been considering a 203* thermostat, subscribing and what it I hear about a better water pump?
Oh, and bc2sv, nice country out there. About 9 or 10 years ago during the winter months when I was driving a puny 89 Toyota pickup (Though I could not get it stuck) 4X4 I met my wife. I was pulling data cable and she was tending to the till, and might I add quite nicely!
Well to make a long story short we married one year later and now have 1 boy and 2 girls. I couldn't have found a better teller if I wanted to, lol
Oh, and bc2sv, nice country out there. About 9 or 10 years ago during the winter months when I was driving a puny 89 Toyota pickup (Though I could not get it stuck) 4X4 I met my wife. I was pulling data cable and she was tending to the till, and might I add quite nicely!
Well to make a long story short we married one year later and now have 1 boy and 2 girls. I couldn't have found a better teller if I wanted to, lol
Snowboard season cometh..
Joined: Jan 2006
Posts: 5,406
Likes: 1
From: Gulf Coast of Florida
I have the 203 in my rig, but before I did any towing (over 2000lbs anyway) I put in a 6.0 tranny cooler. I don't know about the engine oil, but my tranny has stayed plenty cool. Given recent discussions, and that tidbit from Layson about TE's stand on the 203, I've considered going back to the OEM part. It's not hard to change, so why not?
Postmaster
Joined: Jul 2004
Posts: 3,156
Likes: 0
From: Yuba City, CA.
I have the 203* and have not noticed any adverse affects, but I don't have a real coolant temp gauge or an oil temp gauge. I do think it has an affect on tranny temp, and therefore will be changing mine.
Lead Driver
Joined: Jun 2003
Posts: 8,298
Likes: 25
From: Damon (South East Texas)
I "had" the 203* and switched back to the stock 195*. During my live tuning, it was discovered my EOT was a bit high for Jody's liking. I switched back when I installed my new HPOP. No use heating the oil more than necessary. I did notice that differences in EOT affected the ICP by ~30-60 psi, during my datalogging. I'm sticking with the stock t-stat.
Even though the trans fluid goes thru the radiator trans cooler (OTW) then the OTA trans cooler, I don't think it affects the trans fluid temp that much. Going to a bigger OTA cooler will negate the hotter t-stat's effects anyway. I was more concerned with engine oil thermal breakdown and viscosity changes.
Even though the trans fluid goes thru the radiator trans cooler (OTW) then the OTA trans cooler, I don't think it affects the trans fluid temp that much. Going to a bigger OTA cooler will negate the hotter t-stat's effects anyway. I was more concerned with engine oil thermal breakdown and viscosity changes.
Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
Just get a bad one out-of-the-box, ONCE, and see what you do for the rest of your years!
Cheap insurance.
This engine has a specific-design thermostat, and aftermarket ones usually are NOT the correct ones, as they don't properly seat the bypass disk. If you get a new one, it's best to buy it from Ford, just to be sure. Or, take your old one to the parts house and accept nothing that doesn't look identical.
Pop
Hotshot
Joined: Jul 2003
Posts: 12,177
Likes: 40
From: Newport, WA
I've read more bad reviews on the 203 stat than good ones. IF I were tempted to try a 203 stat, I'd try to see if I could get one from IH and boil it before I installed it. When it comes time for me to replace it I'll be getting a factory replacement stat.
Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
Get it from Ford, not International.
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Hotshot
Joined: Jul 2003
Posts: 12,177
Likes: 40
From: Newport, WA
The thermostat housing (water pump) used on the International T444e is of a different design than the Ford Powerstroke. It's just one of those "little things" that Ford changed when using that basic engine. Along with that change came a different thermostat, too.
Get it from Ford, not International.
Pop
Get it from Ford, not International.
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Senior User
Joined: Jun 2008
Posts: 151
Likes: 0
From: Western WA
The thermometer doesn't help with max cooling. It will keep the engine a bit warmer when operating under light loads (i.e. idle, down hill). It only changes the minimum temperature.
How often is your engine operating a minimum temperature? If a lot, then I can see a 203 thermostat benefiting you.
I didn't notice a difference. Nor does the cab feel warmer. The stock temperature gauge still reads under half.
Will your engine benefit? Perhaps, but the amount is unknown. No one is going to tell you that you are going to squeak an extra 10K miles out of your engine.
And from what I've read, International uses the 203º thermostat. But that doesn't mean International is better or knows something more than Ford. Sometimes application has more to do with it. Perhaps commercial trucks spend more time at idle when docked and they needed the engines warmer, where Ford passenger trucks spend more time moving, therefore higher minimum temps aren't a need.
I'd do the modification if you want to spend the money to make yourself feel good.
How often is your engine operating a minimum temperature? If a lot, then I can see a 203 thermostat benefiting you.
I didn't notice a difference. Nor does the cab feel warmer. The stock temperature gauge still reads under half.
Will your engine benefit? Perhaps, but the amount is unknown. No one is going to tell you that you are going to squeak an extra 10K miles out of your engine.
And from what I've read, International uses the 203º thermostat. But that doesn't mean International is better or knows something more than Ford. Sometimes application has more to do with it. Perhaps commercial trucks spend more time at idle when docked and they needed the engines warmer, where Ford passenger trucks spend more time moving, therefore higher minimum temps aren't a need.
I'd do the modification if you want to spend the money to make yourself feel good.
Junior User
Joined: Nov 2004
Posts: 98
Likes: 0
my two cents. don't install. it takes btu's to make heat. and I have found my mileage suffered just ever so slightly however I have found no value added and the clutch fan engages sooner now and I don't like that with the stock one the clutch fan while towing hardly ever came into play.
Senior User
Joined: Jun 2008
Posts: 151
Likes: 0
From: Western WA
my two cents. don't install. it takes btu's to make heat. and I have found my mileage suffered just ever so slightly however I have found no value added and the clutch fan engages sooner now and I don't like that with the stock one the clutch fan while towing hardly ever came into play.
The thermostat only affects minimum temperature. While towing, I hardly believe you are towing a minimum temperature.
Slight mileage differences can be caused by many circumstances: headwind, season, temperature, altitude, fuel quality, driving conditions, tire pressure, weight (like an extra passenger or junk in the pickup), etc.
Jake
Post Fiend
Joined: Jun 2004
Posts: 9,293
Likes: 10
From: Parker, CO
A 203* thermostat will never go in my truck. There are reasons why.
For very light cruising on the highway (while empty), a 203* thermostat won't hurt anything. It might even slightly increase mileage as Clux pointed out.
However, that's where all the benefits stop.
Oil temps typically run about the same as coolant temps when cruising empty on a highway. Once you get into stop and start traffic (where you are accelerating more often rather than holding a steady speed), towing, hauling a load, or anything that puts more strain on the engine..... oil temps will rise higher than coolant temps. How much of a rise really depends on a lot of factors, such as mods, your driving style, how much load you are putting on the engine, ambient temps, engine health, etc.
Now for the fun part. The PCM relies quite a bit on oil temps when it comes to fueling and timing. By default, the normal operating range for oil temps stops at 235*. Any higher than that and it will affect drivability, as your fueling and timing maps will change.
With a 203* thermostat, some people can have oil temps approach or go over 235* in certain situations. When this happens, you'll begin to lose power and mileage, and it will get worse as temps rise higher.
So there's my 2 cents.
For very light cruising on the highway (while empty), a 203* thermostat won't hurt anything. It might even slightly increase mileage as Clux pointed out.
However, that's where all the benefits stop.
Oil temps typically run about the same as coolant temps when cruising empty on a highway. Once you get into stop and start traffic (where you are accelerating more often rather than holding a steady speed), towing, hauling a load, or anything that puts more strain on the engine..... oil temps will rise higher than coolant temps. How much of a rise really depends on a lot of factors, such as mods, your driving style, how much load you are putting on the engine, ambient temps, engine health, etc.
Now for the fun part. The PCM relies quite a bit on oil temps when it comes to fueling and timing. By default, the normal operating range for oil temps stops at 235*. Any higher than that and it will affect drivability, as your fueling and timing maps will change.
With a 203* thermostat, some people can have oil temps approach or go over 235* in certain situations. When this happens, you'll begin to lose power and mileage, and it will get worse as temps rise higher.
So there's my 2 cents.