2013: Overheated and Boiling... HELP!

[POS13Ford]

Replaced radiator, water pump, thermostat and all coolant hoses recently. Three months later, I'm driving down the road it starts overheating and boiling through the cap on the expansion tank. Any ideas? Thinking maybe the cap itself or even the thermostat.

 

[Steve8316]

Did you do some diagnosis that led to either the cap or t'stat? Or are you just guessing?

Overheating is one thing - boiling is another. If you caught it when it boiled, it probably DIDN'T overheat. If it starts & runs smoothly again, then it CERTAINLY didn't overheat (which is a catastrophic event that requires rebuild or replacement).

What did the temperature gauge show when it was boiling? How many miles/years on the cap? What brand/PN/source for the pump, radiator, & t'stat?

 

[POS13Ford]

It overheated going down the highway on me. Driving along at 70 mph all of a sudden the thermostat shot all the way up into the red and the stop engine light came on the car. I pulled over, shut it down and let it cool down before popping the cap to find most the coolant was gone, even though I had just checked at the day before. I got it towed to the house and filled the coolant tank. I didn't start it again, because I was on my way out of town and didn't have time to mess with it. So, it sat for a week before I topped it off with coolant again and fired it up to let it run. After about 5 minutes the thermostat shot up again and coolant started blowing out from underneath the expansion tank cap.

 

[Steve8316]

The thermostat doesn't move, and has no red - that was the temperature gauge. The PCM/BCM/ICM is programmed to do that when the engine gets hot, but BEFORE it actually overheats.

So you didn't see anything come out the first time, right? Did you check the oil level? Who did the actual labor to change the water pump & other parts? To what brand & PN, from what source? How many miles did it do in those 3 months?

 

[Josh P]

I'd test for compression in the coolant.