203 T-Stat ?
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Joined: Sep 2003
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From: Houston, Texas
Speaking of RTV, this stuff works well, slather it on: Permatex/3.35 oz. (95 g.) tube Ultra Black maximum oil resistance RTV silicone gasket maker (82180) | RTV Adhesive | AutoZone.com
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Joined: Jul 2008
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From: N.GA Mountains
I've been running Bob's 203* t-stat for 250k miles in my F350 and over 100k in the X. I would not put much stock in this mod increasing MPG more than changing your driving habits can...
Yes, the heater gets hotter - and faster with the 203* 'stat. I have a ball valve on my heater core supply and CLOSE it in summer for coooold AC.
The reason the billet housing can leak is because it is 100% FLAT - the cast water pump is often not.
The flimsy stock housing is more forgiving to imperfections in the water pump. I've had a couple water pumps on each of my PSD's and some worked with just Bob's o-ring and some needed RTV to seal. 
Yes, the heater gets hotter - and faster with the 203* 'stat. I have a ball valve on my heater core supply and CLOSE it in summer for coooold AC.
The reason the billet housing can leak is because it is 100% FLAT - the cast water pump is often not.
The flimsy stock housing is more forgiving to imperfections in the water pump. I've had a couple water pumps on each of my PSD's and some worked with just Bob's o-ring and some needed RTV to seal.
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From: ellensburg
I will say one thing...after running the 203* for the last 2 years, I am going to go to the 180* t stat. I'm running dual terminator pumps, and my oil temps are a little high for my taste with the 203*. However I did love it with the stock HPOP. Faster Warm up, and seemed to be a bit better mileage. Like .2-.5 maybe 1.
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Hotshot
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From: N.GA Mountains
I have heard that before. What EOT's are you seeing and what conditions?
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From: ellensburg
Cruising empty I've seen as high as 220...normally sits around 214. I hear a noticeable difference in the engine when the oil temps get around 210, might be something that can be changed with tuning, might not. Either way, I'm going to swap them out and see if things change. If not then I'll take a look into my tuning and see if its there. I love the heat, but on long trips I feel like its getting the engine too hot with the dual pumps.
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The heat works much better. It might run quieter or my hearing is getting worse. Towing in 80T, I was seeing between 210 and 217 for oil temps. I also have a leak that is from the billet housing. I am going to try the Dorman gasket. Are you guys using RTV with the new Dorman gasket?
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Joined: Feb 2012
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From: Western AR
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From: Houston, Texas
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I recently installed the 203* and housing and no issues at all. Seems to be getting a little better MPG but have only one fill to go by. 16.3 around town and filled to the neck, not sure about the previous fill though. No hutch or harpoon yet.
Mike
Mike
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From: Western AR
I just went back to the 195* IH thermo with my new pump, and the wife is already commenting the heater gets going quicker in the morning. Some have already said they have observed this, and now I have, too.
Veteran/Sheepdog
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From: Western AR
I don't think Dorman is doing anything special besides cutting the gasket thicker...and they are probably doing that by accident!
