I would be fine with a factory thermostat if it worked as designed. The idea of mixing coolant thought a bypass is a good one. In theory it should keep the block temperatures more stable by not allowing cold coolant from the radiator straight into the engine. Too bad it doesn't work and the temperatures fluctuate from 180 during normal driving to 220 when sitting in traffic. Constant heat up, cool down is probably not the best thing for the engine.

 

I agree DArt.
Since I have replaced my non working fan clutch with a working one my truck stays right at 196-198* unless she idles for more than 20 min, then the temp will get upto 200-205*.
Even without a working fan clutch my truck ran 196-198 on the road and 200-205 at idle, but that was like stopped at a light idle time not 20 min.

 

And I read through the Polaris Labs link that you posted and they say right in there that "if you have a corrosive coolant" problems are magnified.
So DII's with corrosive coolant (Dex-Cool) will be more prone to cooling system problems than other engines.

 

So Spike,
After reading all this discussion. What brand of Coolant do you use other than the Dex-Cool? Peak, Peak Global(which I can never find) Prestone, Polar.
Just curious after we have determined that Dex-Cool is no good.

 

I use Peak Global Lifetime 50/50.
I have also used Prestone in the 50/50.

Just use a name brand ALL ALUMINUM safe coolant in the 50/50 pre-mix.
You CANNOT use tap water and no way in hell should you use well water to fill your radiator unless it is a emergency.
Tap water has calcium, fluoride chlorine and other minerals in it.
Well water has heavy minerals and rust in it.
If you buy it pre-mixed (I know its cheaper per gallon straight, but trust me on this) most companies will warranty your cooling system, mix it yourself and you are on your own.
You buy it pre-mixed and your block freezes and cracks, they will fix it.
If you really want to mix it yourself then go to the store and buy distilled water and mix it yourself 50/50, pour in half gallon of straight coolant and half gallon of distilled water, repeat until full.
Then after driving for a couple of days you will need to check the freeze/boil point of your coolant.
If you buy it pre-mixed it will say right on the bottle what the freeze/boil temps are.
usually -34*F.
The stuff I sold was my companies brand but I was told it was Peak Global but I could never confirm that.
Also know that all modern engine coolants now have a bittering agent added to them so they non longer taste sweet.
Kids think it is Kool-Aid, drink it and die a slow painful horrible death.
1 tsp of straight coolant will kill a 200lb healthy man in less than a week with kidney and liver failure.
Companies like LR and GM use Dex-Cool because it is more environmentally safe than the "green stuff".
You get in a accident and explode your radiator where does that coolant go?
Storm drain, then stream, then river, lake...it kills fish, frogs, squirrels.
Make a fleet of cars that get 0mpg and you pay heavy fines.
How do you help offset those fines?
Make your fleet more enviro friendly.
How?
Enviro safer coolant, longer oil changes...less pollution fewer fines.
Its pretty simple, the less you pay in fines the more money you make.
The less hot water I use the less my gas bill is each month.
Economics 101.

 

Getting ready to do the install and realized im not sure which direction does the thermostat point for this mod? Thanks!

 

Goodness, children! When did we get off topic? Sorry to rain on your little argument here, but I thought we were trying to figure out how to do this mod.

Thanks, Josh, for your write-up as usual. Will you be adding this to your website as well? It's nice to go to a central repository for a lot of maintenance and preventive maintenance items.

If you want to do this mod, then why not do it and find out what it's like over the course of a year? What could it hurt? Besides, I like to think of it as free research. It takes someone out there with the ***** to try something out for the rest of us to gain any benefits, so why not?

Sorry, fellas for stepping on anyone's toes. You guys are all trying to do the same thing, just going at it different ways.

 

The spring part points toward the engine.

 

Just to understand, so direction of coolant flow is hot water out of the engine up through the pipe over the alternator, through the new thermostat, to the radiator top inlet, out the bottom of radiator back to water pump into the engine, right?

 

That is correct.