I topped off through the bleed screw this morning. It took about half a Solo cup, 8oz. I'll drive it this afternoon and report back on the temps.

 

If you have a hard time getting the air out, work your way around every water connection and test your clamp tightness and make sure the hoses are seated all the way. One or more semi-loose fittings is all it takes to introduce air into the system, and it won't necessarily leak a noticeable amount of water.

 

Check the hard to see places as well. Coolant temp sensor on the lower Intake (and the throttle heater nipple right next to it) ,throttle body header plate, etc.

 

There are absolutely zero leaks on the new engine and cooling system. All the hoses, clamps, oem 180 thermostat, and radiator are new and installed meticulously. New HD fan clutch(with new fan blade) and aux fan work perfectly. Drove it a bunch today. It is so smooth and quiet! Temps were as follows: normal highway and back road cruising, 185-201. Uphill grades and bumper to bumper traffic, 201-206. Idling at red lights, 206-208(saw 210 for a brief moment at a long red light). For the most part, it averaged around 197. Any higher temps dropped fairly quickly once I was moving or not pulling a long uphill stretch. Outside temps today averaged 85 and very humid. My A/C was on Low and cranking. I'm really confident in these temps for an 04 with a 4.6 and no oil cooler. Would 208-212 for a few minutes at a time in 85°+ weather be cause for concern? My view is that anything below 212 should be absolutely fine since the aux fan is designed to only kick on, other than A/C use, at that temp. Any thoughts or comments on the temps I'm seeing are much appreciated. More to follow...Cheers!

 

i would say those temps are well within normal.

 

Looking good! Keep checking the bleed screw for levels every few days and top off as needed until you are confident there are no bubbles of air left. The air bubbles will settle at the bleed screw as it is the highest point.

Even though it is hot out, you may want to run the heat at full blast for a few moments as there may also be a few air bubbles trapped in the heater core.

 

Thanks Dave. I'm going to check it each morning for another day or two. I've cranked the heater for a few minutes at a time going down the highway. It was plenty hot! I wanted to make sure the heater core was fully bled of any air pockets. I think it's running pretty solid in these 85°+ temps. It's a joy to drive with the new engine!

 

humans feel hot in humid weather, but Humid weather cools the radiator much better than dry weather, cause water is a lot better heat conductor than air,,
Even though your temps are with in factory specs,(& those specs are mostly for emission control not engine longevity), but best operating temp for any engine is between 177*f to 185*f,,
Now that doesn't mean that hitting higher temps will destroy the engine right away, but it will definitely shorten its life in a long run,, & it will vary depending on the engine itself,,
I have two 4.6 D2's, (neither one has oil cooler) both used to run 200 to 206*f in long uphills in high (+90*f ambiant), but never more than 197*f even if parked with A/C on for whatever length of time,, even though acceptable it was too much in my opinion, so I experimented with their cooling system for long long time, & modified it so now in worst uphill case they don't pass 197*f,,
If I am cruising below 65mph, no matter how hot the ambiant is they never go over 187*f, & most of the time it's around 183 to 185*f,, and at stop lights it doesn't change more than couple degrees,, at night driving its around 177 to 182*f,,( the numbers are all with A/C on,) actually in city driving they run cooler with A/C on, in Hwy driving 2 to 3 degrees cooler if A/C is off,,,
All I am saying is any cooling system can be modified to run cooler & add to the life of engine,,, ( I did mine by doing an inline T-stat & adding a small radiator & some aluminum tubing that run parallel with main radiator & provide additional cooling, didn't cost very much, but took a lot of work & experimenting), but that's just me, I get paranoid when I see temps that are more than 195*f,,,

 

I just ran mine yesterday pretty hard. 6% grade, 10 miles up hill, 95 degrees out, AC on full, rig was loaded for overnight trip, engine temp never climbed over 194 degrees.