ok so i put in a new heater core (old one was bad) put in a new t-stat(spring on the old one was broken) flushed the coolant system 3 times(with a professional flush machine from the dealer ship i work at) all the air is out of the system. but still when driving my heat does not get that hot, but inside my shop ideling it gets nice and hot. what could be the problem? should i put a small piece of cardboard? install an electric fan with a thermostatic switch? any other ideas guys?
Faulty T stat (stuck open) Heater controll valve stuck shut (if ac equipped) Bad water pump impeller (rusted off/loose on shaft)Plugged up heater core.Big giant radiator(too efficient/not likely) Air in heater core/cooling system. Blend door in heater box not opening.Lack of air getting into heater box(not likely unless your cowl is sealed off or full of junk) I am sure theres more but...Its late,brain shutting down.Good luck!!!
Frank, I have seen cowls/heater boxes soo full of...crud/nests that the blower couldnt circulate any air to push the heat into the car.I did also say it was not a likely scenario.(not likely unless your cowl is sealed off or full of junk)Easy enough to rule out...
Low water in the radiator is usually what does that to mine. Vacuum leak preventing the ducts from opening, valve on the heater line not opening. My first Comet required me to raise the hood and manually open the hose to let hot water into the core.
id say if its ok idling in the shop then id want to know what the engine temp is going down the road.
thats my guess. maybe because it's so colad out and the air naturally moving over the radiator(being that it's subfreezing) is cooling it down a lot. hence my cardboard question...lol. i never thought about my water pump being bad though. i flushed the cooling system soi much because it was BROWN but now it's fine.
Check your water pump...May hav a lack of impeller blades due to rust(reason the coolant was brown = rust)
