Join Date: Nov 2018
Location: South Mississippi
Overheat and Heater issue
I need help. I realize that diagnosis is difficult over the internet, but I'll try to give as much information as possible to see if it narrows down things.
Vehicle: 2006 F250 Lariat FX4, 240K miles.
Not long ago, I started getting a quick spike in coolant temperature with a notice to "check engine temperature." The spike would last about 30 seconds and immediately go back down to normal. This would happen after driving it about 10 minutes, and it may then randomly happen again or not at intervals.
In addition to the engine temperature, I also noticed that the heater would blow cold air, and then suddenly blow a burst of hot hair for a short period of time, then go back cold.
I never noticed any puking coolant from the degas bottle, but I can't confirm that.
This seems to me to be a thermostat issue.
Well, last weekend, I changed the thermostat. I had to add a good bit of coolant afterward.
Engine Temperature notices stopped. Heater started to blow hot air. But after a few days, I noticed that the heater in the cab would cut off and start to blow cool again. It seems that when I accelerated and then let off, it would blow hot, but only for a short period.
Yesterday, coming home from work, my engine temperature spiked again just like it was doing before. It dropped back off to normal after about 30 seconds. Since I was close to home, I was able to check if I had puked any coolant. I didn't notice any coolant on the outside of the degas bottle, but I did see some moist areas under the truck that makes me thing it may have.
The truck is supposed to be studded, but I am no mechanic. But I don't think that it is a head gasket issue (but won't rule it out categorically.)
However, I am not getting any losses of power at all. I am not seeing any white smoke at any time.
So... I need your help.
Is it possible that I just got a bad thermostat? The one that I got was a Duralast from Autozone.
My other thoughts could be that I need to flush or replace heater core and/or water pump.
Thanks in advance for any help or insight that you can provide.