Let's review the progress on cooling. When I first got the truck, it had reached 224 degrees and blown out significant coolant. Lets fast forward to now, it hasn't gone over 202 to 204 degrees and discharges very little coolant in worst case scenarios like a long steep grade in cruise control trying to maintain 65 mph. If I take it out of cruise, keep an eye on temp, turn on the fan lockup switch if it climbs over 195, I have no problem. With the electric fan installed, it is maintaining temperature even better, and with this coolant system modification, you can see the coolant level being pulled down in the degas bottle, as the waterpump is pulling coolant out of the degas bottle which keeps degas pressure lower. I'm pretty sure the two coolers atop the engine are doing their intended job condensing steam and cooling what goes into the degas bottle. My heat gun measures a 20 to 24 degrees drop in temperature from input to output. The volume of coolant passing through these coolers is insignificant to the engine, but to the degas bottle it is a significant drop in temperature and judging by the amount of coolant purge declining, it's reducing pressure through condensation.
So temperature isn't the issue anymore as the typical temp range is 180 to 186. On hills or pushing 70 mph in an 80 mph stretch of freeway, temps will climb to 194 where I will turn the fan lockup switch on. The electric fan has reduced the need to do this. It is pressure that is the problem, and these headgaskets test good so give up that argument. My current suspicion is the heads are creating a lot of heat and I know these heads are considered hot especially the rear cylinders. There is a kit made to route a couple hoses to the rear of the heads to improve cooling but that would have to be done with the heads off. My current guess is the engine has been given a tune for more power and that would cause heat in the heads. I'm looking to use my Insight Edge3 to retune the engine to their tow setting which is supposedly 20 hp over stock. That's where I belueve it sits for now. Obviously, what I have done to the truck and engine isn't a waste and is in fact working quite well.
Incidently, the height of the Curt spare tire mount is too high placing it right in my field of vision. I believe it was designed for newer trucks where the front hitch mounts down lower than mine. I'm considering cutting 6 or 8 inches out of it to lower it to where I can see forward without obstruction. Im also considering mounting to a a stinger but then I'd have to worry about departure angle on some of the roads we take Take care...
