Had a weird coolant leak on a Ford 5.4L that I chased for a week

I mean, I kept looking for a head gasket or a cracked block, but it was just a tiny split in the plastic coolant crossover pipe under the intake. The customer mentioned the temp gauge would spike for a second then drop, which was the clue. Anyone else seen this specific failure before?

3 comments

3 Comments

emerycarr12d ago

You said you looked for a head gasket or cracked block, but that temp gauge spike is the classic sign of an air pocket. Those plastic crossover pipes are a known weak spot on that engine, and when they leak they let air into the system. That's what causes the quick temp spike before it drops back down.

joseph_roberts11d ago

Wait, but how bad is it really? Emerycarr makes it sound like a ticking time bomb, but a small air pocket and a quick fix doesn't seem like the end of the world. I'd just keep an eye on the temp and swap the pipe when I could.

zara_hill4612d ago

Honestly, is that crossover pipe leak even a big deal? It sounds like a cheap plastic part that just needs a swap. People act like every little thing on that 5.4 is a major failure waiting to happen. Sure, it causes a weird symptom, but finding it seems like the hard part, not fixing it. I'd take that over a real head gasket job any day.