Re: Heat cold when idle?
It's also possible that you both still have air bubbles in the system. I know the 5.7 is difficult to get the air out of if you don't remove the little bleed plug on the water pump when filling. The coolant level keeps going down as the air comes out. I just changed cams on my Hemi LX and fill with the plug removed until it comes out the plug hole. Let it sit a little while and add more coolant until it comes out again. Do this until coolant level stays right at the bottom of the hole. Replace the plug (use teflon tape or pipe dope on it) and run it. On my Hemi, I still had to add two or three more times (without removing the plug now) until the level in the overflow tank no longer changes. I leave it sit overnight with the hood open in the garage and check/add in the morning to the "full cold" level. I do it this way just so I remember to do it. Once it has stabilized for 3-4 days, I call it good. After doing my LX I even had to add maybe a cup of coolant after a 275 mile trip. It's been OK for nearly a week now, so I think it's got all the air out. Don't know if the 3.7's and 4.7's have the same type bleed plug or not, but you guys may want to check. It should be high on the water pump (1/4 in. pipe) right next to the thermostat housing if you have it. Also, when you install the thermostat you should make sure the bleed hole in the thermostat is at the top. This also helps get the air out. Good luck and let us know what you find.
05 LX/RT and 06 WK/GCO, (modded similarly) with MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tubular headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 85mm TB, SOS Coils/.060 spark plug gap.