Fixin to flush the truck and replace thermostat. Couldn't help but notice the stock thermostat housing looks kinda crappy. Any advice on how to clean it up good and maintain a good mess free seal after flush? I'm kinda on a budget and don't want spend money on a billet one. Also is the 203 doeselsite thermostat a placebo or does it actually do anything?

 

Riffraff diesel sells a stock replacemen for $23 I believe. I just bought all the parts to replace the water pump on mine. Pretty cheap for a stock replacement and piece of mind.

 

Just buy a new one.
http://www.riffraffdiesel.com/riffra...ostat-housing/
or OEM http://www.dieselorings.com/1999-200...otorcraft.html

 

I cleaned mine with a wire brush on a 4" angle grinder and then painted it with some krylon I had laying around about 3years ago and have had no problems. The 203 is not worth it. Did it then changed it back. The engine oil temp went up with the change.

 

So the 203 thermostat is a definite no and I'll just buy new housing from riffraff. Thanks y'all. Glad I'm on this forum.

 

I swapped in the 203 thermostat when I installed the IH water pump and have seen nothing to show that it made anything worse or anything better. Truck runs nearly the same with either stat.

 

Yep good call on the riff Raff billet piece. And I'm going to try riff raffs 180 thermostat

 

As stated, replace it. The cost is low. You also may bend/tweak the stock one when you try to remove it.

I do not recommend going the 203* thermostat. I believe the original selling point for it was to increase your mileage. From all the feedback I have heard from it, this has not been the case. It mainly just causes oil temp issues for guys working these trucks hard.

 

Justin is probably right, but I plan to run the 203 until I have to take the housing off for another reason other than just to replace it with a lower temperature one. I do get 18.5 MPG unloaded and 12 MPG loaded with our 36 ft 5th wheel trailer though, so maybe the 203 helps, maybe it does not.

Honestly, I probably would have just gotten the 192 to fit the IH pump when I bought the pump 2 years ago if I had been more educated on the subject. It is what it is though...

Glad we could help out with your decisions.

 

I have to admit though, the sales pitch of the 203 was gettin to me haha. Dang, 18.5MPG sounds like a dream, wouldn't mind that one bit!

 

18.5 mpg is only attainable with the ZF6 manual tranny. There is a lot of power loss/heat generated with the 4R100 auto even when the torque convertor is locked, especially when towing. Flat terrain is very helpful too!

 

That explains my 10mpg last weekend, well that and a bad case of get there itis

 

This is what I have. Since it is mating to a cast iron surface I put a small bead of RTV around the edge to ensure a proper seal. The 'new' thermostat design has a gasket around the circumference so it might not be needed any more. I laid a bead anyway as I wasn't interested in putting it all back together and topping it off to find out it leaked.

 

Do you, by chance, monitor your oil temp when towing your 5th wheel? I am curious what kind of oil temp you can see with the 203*. That 36ft 5th wheel should weigh in at around 12k at least when loaded. I have the same setup, and mine normally comes in at around 14k. With the stock 192* t-stat, I see oil temp get to around 220* max. The fan usually comes on at around 215* and doesn't let it get much higher. Mind you, this is towing a 6% grade at about 100* ambient.

 

Justin, I have not yet monitored the oil temp. I can tell you that the fan never came on 2 weeks ago when we pulled the trailer home 1000 miles from WI to GA. When going through the mountains in TN and NC we had zero problems and the fan never came on. (knock on wood) We were getting 13 MPG with the 5th wheel through WI and Illinois, but had a pretty good tail wind, so I threw that figure out as a fluke. The 18.5 unloaded is city and highway over various terrain including north GA mountains. The 12 MPG with the 5th wheel is average from 700 miles which included plains and the mountains of eastern TN and western NC.

Last summer when we towed our 10K lbs travel trailer to Seattle from GA, the fan came on, but only during the heat of the August day when traveling across SD (Badlands area) and MT (Western mountains).

The fan never comes on when running unloaded, only when towing heavy and in hot ambient temperatures.

I have the 192 degree thermostat saved in my Amazon list for future purchase as it is the specialized short one for the IH water pump. Although, I don't plan to replace it anytime soon unless I have to drain the coolant or there is a leak of some sort that needs to be addressed. I feel that the lower oil temperature may be a good thing, but the 203 stat keeps the truck running well at a good temperature it seems.

We are taking the new to us 5th wheel out again soon, I will try to remember to monitor the oil temperature. Although, now that the air temperatures are lowering and we will be headed east where we are not in the mountains I don't see it being much more than 200 degrees.

Just for reference, we bought a 2011 Montana High Country 313RE that weighs in at just under 10K lbs dry and when we bought it the fresh water tank was full with 60 gallons weighing in at roughly 500 pounds. We now have most/all of our stuff packed in it and are ready to set out on our next trip.