As many prolly know, I had my radiator replaced a couple of weeks ago. Before when I noticed that I had a crack in my old radiator when I checked because my heater was blowing cool air, I added antifreeze, which leaked out fairly quickly, but I had hot air from heater and defroster. Now that I have a new radiator, antifreeze is filled and heater is blowing cool air and gets warm when I move, but then cools down again when I stop. It's annoying cause it takes forever for the windshield to de-ice in the morning. Temperature gauge stays normal (about 1/2 way between 100 and 150), and doesn't move. I turn heater off and it doesn't go up so I gather it's not the thermostat or it would probably overheat. Could it be something blocking the antifreeze, maybe heater core blockage or water pump maybe. Is it something I could replace or should I call the place back and ask.

 

You need to check that the rad is full (when cold). There may have been an air lock in it when the rad was replaced and now it's not full.
When you drive, the rpm increases and the water pump circulates the coolant better through the heater. Top up the rad.

 

I would take a guess and say it is possible it is a heater core issue. What I would check though first is with the truck at operating temp. feel the two hoses going into the firewall that connect to the heater core, are they hot or cold???

 

Yup check the hoses. You said that normal temp for you is between 100-150, is that degrees? If so that seems a little low. What may have happened is the thermostat failed in the open posistion. Which is what you want when a thermostat fails. It will preven the engine from overheating.

 

If you have the correct thermostat (195*) then that reading is not normal if the gaugeand ECT areworking correctly. It should be just a tick under 210*.

 

I will check it out tomorrow after som edriving to work and post when I go on my lunch break about the temp and where it is at. I might be wrong, I was trying to think where the lines were. I'm hoping that maybe I didn't put the needle back in the wrong spot when I was doing my gauges. It's quite possible. Anywho, I will top off the rad tomorrow and see what happens then I will check the hoses for the heater core and get back to you. It's just wierd how I would have a rolling furnace with a crack in the radiator and then i get a new one and i get cool air. Shouldn't it be the other way around.

 

Yea it should but vehicles are weird like that but sometimes fixing one problem leads to another!!

 

Isn't that how it always goes [:@]

 

bump!

I popped the radiator cap off and the antifreeze was all the way to the top. I felt the hoses going to the heater core and they are both hot. My dad mentioned something that maybe they set the thermostat too low. I didn't know there was a seting, or is there? When I turn the heater on number one setting, it comes out not as hot as it used to be, but hot enough. Then the higher I go in the numbers, the cooler it gets. I'm stumped [:@]

 

What does the temp gauge on the dash read? If it reads on the cool side, it is possible that the t-stat is either too cool or failed partially open.