203° Thermostat - Diesel Forum

Ryanspowertroke · 10-09-2009, 01:20 PM

Is it a mod worth doing or not??

PRDATR · 10-09-2009, 05:01 PM

Do a Search. Some have had positive results while others have shown no benefit.

butchcassidy1 · 10-10-2009, 08:05 PM

If you are looking for more heat, then yes, it will give you that, BUT, that is it.

If you are looking for better MPG - forget it, you can get better MPG by keeping the truck light, no lifts, nor oversize tires, speed under 60, and treat the go pedal like an eggshell.

If your truck gets checked for emissions with this tstat, do not be surprised if you are not passed on the emissions test.

Hopes this helps,

Butch Cassidy1

O

**SmokeyWren** · 10-11-2009, 11:10 AM

Ford engineers determined that 195° was right for the thermostat in our 7.3L PSDs. I haven't seen any evidence that the Ford engineers were wrong. So I'm on my third Ford OEM thermostat in 10 years and 185,000 miles.

snakyjake · 10-12-2009, 01:41 AM

If you cooling system temperature is above 203º, then it won't matter which one you use, and it will not provide you more heat.

What is your idle temperature?

What is your unloaded cruise temperature?

What is your loaded temperature?

**bigb** · 10-12-2009, 10:57 AM

I decided to go with the 203* because my truck sees a lot of short trips. Also I never tow anything.

Teknobenji · 10-12-2009, 12:00 PM

Quote:

Originally Posted by butchcassidy1

If you are looking for more heat, then yes, it will give you that, BUT, that is it.

If you are looking for better MPG - forget it, you can get better MPG by keeping the truck light, no lifts, nor oversize tires, speed under 60, and treat the go pedal like an eggshell.

If your truck gets checked for emissions with this tstat, do not be surprised if you are not passed on the emissions test.

Hopes this helps,

Butch Cassidy1

O

Why would that change our emissions? our worst emissions are at idle after startup with a nice cool engine.....
( I am just curious - have always run the OEM Ford thermostat myself)

missmanj · 10-12-2009, 03:54 PM

Quote:

Originally Posted by Ryanspowertroke

Is it a mod worth doing or not??

only if you like more heat in the winter, otherwise no benefits at all what so ever, had it installed for over a year.

snakyjake · 10-12-2009, 04:01 PM

Quote:

Originally Posted by missmanj

only if you like more heat in the winter, otherwise no benefits at all what so ever, had it installed for over a year.

You need to qualify this. What is your operating coolant temperature?

If your coolant temperature is above 203º, it won't matter what thermostat you use.

**DIESELSITE** · 10-13-2009, 12:43 PM

Quote:

If your truck gets checked for emissions with this tstat, do not be surprised if you are not passed on the emissions test.

Hopes this helps,

Butch Cassidy1

Based on what knowledge or experience? Your use of the wrong International thermostat? We've been over this before Butch. You bashed my thermostat for years insinuating you bought from us until I posted you never bought mine and you had to admit you bought a short stem International stat.

Quote:

Ford engineers determined that 195° was right for the thermostat in our 7.3L PSDs.

and to complete the sentence........ to meet the new OEM emmision requirements. (whether testing to determine the difference even existed or not).

To use your logic, the Ford engineers

Quote:

I haven't seen any evidence that the Ford engineers were wrong

decided the International engineers were wrong. So, who was right?

Bob

**DIESELSITE** · 10-13-2009, 12:58 PM

To further note that since all current and future emmissions tests that I know of rely on visual smoke, and the fact that a hotter engine reduces particulate emmissions (soot), then the thermostat should actually help more trucks meet the new emmissions testing coming down the road.

Bob

Rickie · 10-13-2009, 01:56 PM

Has anyone had to remove their 203* Stat because of failed emissions?

It's an interesting point, emissions in diesel. If you change something to reduce soot, such as increase combustion temp, you increase NOx. If you reduce combustion temp, NOx goes down but soot goes up. Future diesel emissions standards will require hugely reduced particulate matter and NOx, that's why we will have Diesel Particulate Filters and some sort of Selective Catalytic Reduction system for NOx.

snakyjake · 10-13-2009, 02:06 PM

What was your water temperature at the time of emission test?

This is fairly simple...if your temp is above 203º, it won't matter what thermostat you use.

444-4D · 10-13-2009, 02:13 PM

Quote:

Originally Posted by snakyjake

This is fairly simple...if your temp is above 203º, it won't matter what thermostat you use.

Why do you think this?

snakyjake · 10-13-2009, 02:32 PM

Quote:

Originally Posted by 444-4D

Why do you think this?

Because with a 203º thermostat, when the coolant temperature is above 203º, the thermostat is fully open.

If you have a 195º thermostat, it fully opens at 195º. This will include all temperatures above 203º too.

So at 203º, both thermostats will be fully open, allowing full flow coolant to run through the system.

When temperature is below 203º with a 203 thermostat or 195º with a 195 thermostat, both thermostats are operating identically. The is because they are both closed.

The above is how normal and conventional cooling systems work.

So the talked about differences will be if your coolant temperature is below 203º.

The benefits will be when your engine is between 195º and 203º. This benefit is the amount of time it takes for your engine to warm up between 195º and 203º. Or anytime your engine is below 203º.

It's also the reason why most emissions are emitted during startup.

I'm not sure of the idle temperatures between the Ford or large commercial truck. Not sure if Ford tried solving the startup emissions, idle emissions, or both.

And when doing an emissions test, you can run up your RPM's above idle, which may generate enough heat above 195º.

So again, I'm not sure what emissions Ford was trying to solve.

Jake