What Happened
This isn’t tech-related, but it reflects how I approach troubleshooting: treat failures as systems, not isolated symptoms.
I was driving home when my 2016 Fiesta began to sputter, clank, flash dash lights at me, and finally shut off. Turns out I had a hole in my radiator spewing coolant like a geyser. That wasn’t the worst part.
Initial Diagnosis
After limping it home, I hooked up a scanner and found multiple codes, but two stood out immediately: cylinder 2 and 3 misfires.
Now, the radiator blowing out was already odd considering the hole was in the upper corner, making road debris unlikely. Combined with multiple cylinder misfires, the problem started pointing toward something internal.
Anyone familiar with auto repair can probably see where this was heading. I checked the oil and sure enough, my engine had been churning chocolate milk like it was Willy Wonka’s factory.
Confirming the Failure
At that point, it was pretty clear I had an internal leak: possible cracks, but more likely a blown head gasket.
I still wanted to verify combustion gases were entering the cooling system because I like being thorough. It didn’t take long before the test fluid changed color.
Final diagnosis: combustion gases entering the cooling system caused pressure buildup in the radiator.
Either the degas system couldn’t vent pressure fast enough, or the gases displaced coolant flow enough to create localized hot spots that eventually caused the radiator to give way.
The internal leak also contaminated the lubrication system, which explains the milky oil.
Final Result
After teardown, I confirmed the head gasket failed and the head had warped enough to compromise the seal.