Well I decided it time to replace this unknown Thermostat that PO slap in there when he replaced water pump. Could be 180oF or 192oF or 195oF.


I read that Ford put 195oF in those cause they try avoid put cat converter on there. They use cooler thermostat to reduce emission.

I was look at International T444E they use 203oF Thermostat.

If anybody know Ford and International use same Thermostat size? I was hoping to buy Real International thermostat from Local diesel shop. I don't trust aftermarket thermostat it cost $38 dollars

 

The only 203* thermostat that will work in the ford 7.3 is the one from dieselsite. I bought one but wont use it since in a boiling pot of water it would only open about an 1/8 of an inch. No matter how long it boiled it would not open more than that. I bought the factor one from Riffraff instead.

 

How about a nice, Ford OEM thermo for $28 bucks?

Riffraff Diesel: Motorcraft Thermostat

Stewart

 

USE THE DIESELSITE 203* STAT:http://www.dieselsite.com/dieselsite203thermostat.aspx PERIOD.

 

The International thermostat will not work because Ford uses a different water pump design. If you want the 203* T-stat, this is the only place to get it. The billet housing is nice too.
www.dieselsite.com

 

Read the reviews, a lot of guys went with the 203 but since have changed back due to high oil temps if I do believe. If I am off somebody will step up but I am pretty sure that is what I read because I was going to go with it also but changed my mind after reading the reviews.

 

Maybe I got a defective unit but mine didn't ever start to open until 206* and even boiling in water for over 10 minutes wouldn't open past maybe an 1/8 of an inch. The stock ford unit I bought from Riffraff started to open exactly right at 195 and opened completely like it should. If anyone is going to use the Dieselsite unit, I would suggest checking it out before you put it in your engine. I am not trying to flame Dieselsite but this is just what I experienced. I didn't try and contact them to see if I got a bad part, I just decided to use the Motorcraft original part as suggested by Clay.

Motorcraft part on Left, Dieselsite 203* on right.


On the left, this is the most the 203* unit ever opened. On the right, you can see how much further the Motorcraft unit opened.


As you can see in this picture, when the thermostat fully opens, it comes down and blocks of the bypass port. If the thermostate doesn't fully open, the water will continue to recirculate back through the engine. This is what you want until it is up to the operating temperature but not after that.

 

We don't recommend the 203*F thermostats because if you watch your oil temps they shoot up over 235*F way to easy and are off the charts when towing. There is no reason for your engine to run that hot. I prefer oil temps of 190*-200* daily driving and no more than 215* towing hard personally.

 

Interested that what scare me couple months ago and forgot until last night.

That 203oF from diesel doesn't look quality. Too much restriction flow.

I think I leave thermostat alone until it give me trouble later.

Yesterday I was drive 50 miles it was around 20-25oF but in morning it was 19oF that was fun to start. Oil temp were 170oF is that supposed to be normal? It had leaky oil cooler.

 

You're incorrect. There is no "PERIOD" about it.

There are those that have good reports using the 203, but there are others who haven't, so your absolute is ill-advised.

Stewart

 

I agree with Clay. I've always wondered where the idea to use a 203 degree t-stat came from originally. The IH 4700 T444E trucks are way different than a Super Duty. The water pump, fan, radiator and frontal area of the truck is completely different on those trucks. Seems to me that International might need to use a t-stat that opens a little later because the recovery time is probably pretty quick. They also might need to restrict flow as well to keep from dropping the oil temp too much once the t-stat opens. Not really sure though....just making guesses based on looking at several trucks at our work.

All I know is that the OEM Motorcraft t-stat and associated cooling system on a Super Duty has always been more than capable of keeping oil and water temps under control no mater how hard the truck is working.

 

You should check any T stat before you instal it. Motorcraft, Dieselsite, Stant or any no name brand. They call have a bad one.