I need some help. I have a 98 4x4 with a 318. I bought the truck with no thermostat. I didn't know that he gooped a bunch of silicone on the intake and housing before bolting it back together. It got thru the entire system...and its nasty. I've since replaced the motor, flushed the heater core, replaced all the heater and radiator hoses. My problem is that I'm not getting any heat and the truck is only getting to 150 or so degrees, with the radiator blocked off. I've replaced the thermostat 4 times, and the radiator cap. The only thing left is the water pump and radiator and the water pump was new when I bought the truck and cleaned it as best I possibly could when the motor went in.

Sorry for the lengthy post. Any help is greatly appreciated.

 

Are you reading the gauge as your 150 or some other form I'd get a thermometer and make sure you're actually only at 150 also how's the coolant level

 

I'm reading it off the gauge on the dash. The coolant level is full and new. And I've burped it to the best of my ability numerous times.

 

I'm confused - how did you block off the radiator? Also, what did you use to flush the heater core and what process did you follow to flush it? Lastly, where generally are you located?

 

I'm in flint Michigan. I cut a piece of cardboard and put it between the condenser and radiator. I pulled both heater hoses, flushed water thru both hoses numerous times until it came out clear, blew it out with air and filled it with coolant and put it all back together. The coolant that came out of the heater core was a nasty shade of brown and chunky.

 

Verify that the temp gauge is accurate, or not...... Infrared thermometer would work great. Point it right at the intake manifold where the sensor is.

What thermostat are you buying? (Hint: Skip the 'safety' stats. They like to fail just for grins.) Thermostat is the only thing that regulates engine temp. If the engine really isn't getting up to operating temp, the thermostat is your culprit.

Probably still have an air bubble in the heater core. They are notoriously difficult to completely purge.

 

The last thermostat I put in was an OEM from the dodge dealer. Before that they were auto zone replacements. I've never trusted those failsafe ones. When I burped the system I put the passenger side front on jack stands and held the motor at 2000 rpms. That was the only way and only time I got the truck up to temp. Should also say that both heater hoses are hot and there's no leaks.

 

Is the fan clutch working properly? It does have a fan clutch right?
If fan clutch is stuck in "on" position they thing may not warm up in this weather.

Dave

 

Thermostat should still restrict flow until the engine gets up to temp.

 

The fan is sucking the cardboard to the radiator. I don't have a lot of experience with fan clutches and testing them.