203° Thermostat

[444-4D]

Originally Posted by snakyjake

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.

Jake

Those temps are start to open temps. Full open temps are 12-15 degrees higher.

[snakyjake]

Originally Posted by 444-4D

Those temps are start to open temps. Full open temps are 12-15 degrees higher.

Great! Finally someone that was able to make a comment on my logic

I researched more from your comment, and found your comment to reflect other sources.

My logic will have to be modified a bit. And people need to check their coolant temperature to know if a 203º thermostat (coolant above 215-218º) will be a benefit.

I don't know the normal operating temperature, so I can't say. That's now my missing piece of info.

Jake

[butchcassidy1]

Originally Posted by SmokeyWren

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.

Smokey hits the nail on the head.

Butch Cassidy1

[ACD2]

Normal average operating temperatures on a gasoline engine(may or may not be comparable to a diesel) usually run @ or around 230*F. Anyone with a scan tool can check this. Only advantage I see of having a 203* is idle temps can be higher, and most larger trucks idle more so I can see the benefit of the 203*. I have one, and I do get more warm air when idling than I did before, but that is about the only effect of having it.

[fddriver2]

I had one for about 2 years, worked fine. I did a coolant flush and put in a oem 195* t-stat and new housing. I couldn't tell any difference between them, performance wise. Mileage didn't change enough for me to tell, engine didn't run any smoother or rougher, didn't make any more or less noise.

If I lived up north where the snow flies and the cold is for real I might have kept it, but here in South Florida who needs more heat?

Just my $.02

[fxdwgi]

Originally Posted by SmokeyWren

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.

....I make my living off of Ford engineers who are wrong.