Spent a full day chasing a coolant leak on a 6.7 Powerstroke that wasn't there

Had a 2015 F-250 in the shop with the owner saying it was losing coolant. Pressure tested it three times, checked every hose and clamp, even pulled the turbo to look at the up-pipe seals. Finally found the problem after 8 hours: the degas bottle cap was just weak and letting pressure bleed off slowly, making it look like a leak. It was a brand new Motorcraft cap too. Anyone else run into a bad new cap causing a phantom leak like that?

3 comments

3 Comments

nancynguyen3d ago

That's a rough eight hours for a bad cap. I get being thorough, but swapping the cap first on every coolant concern seems like overkill. Most of the time, a new OEM part is going to be fine. This sounds like a rare fluke, not a common failure. I'd still start with the usual pressure test and visual inspection. Changing your whole process for a one in a thousand bad cap just isn't efficient.

kaid473d ago

Totally get what @nancynguyen is saying about efficiency, but that bad cap story is a gut punch. Makes you question every new part in the box now. I mean, maybe the real lesson is to pressure test the whole system with the new cap already on, before you even start tearing things apart. That way you catch it right away instead of wasting hours. Idk, it just shows that even the simple fixes can have weird exceptions sometimes.

the_jordan4d ago

You saying it was a brand new Motorcraft cap is the kicker. I always thought if it was new and OEM, it was good. Guess I'm adding "swap the cap" to my list of first checks now.