UPDATE: Great day in Moab until my Bronco broke down (Overheating)

[jb56]

I would think that once the heat exited the system the expansion tank would drain through the open hose. It was likely airlocked from the heat in the system and once it cooled down overnight the tank drained.

Just my guess.

Flip had a similar explanation.

I really do hope this is correct, because it's a very simple fix, I'm just surprised that a transmission coolant inlet hose would just "pop off" on a totally healthy Bronco.

On the other hand, if the coolant wasn't being circulated and the engine and transmission coolant lines were very very hot, it wouldn't surprise me if that difference in pressure would cause a hose to come detached.

If the hose coming off caused the overheat, then I'm not really worried. But if the overheat caused the hose to come off, then I'm a little concerned about driving it 200 miles on the highway right after I pick it up.

Maybe I'll just do some laps in town for an hour or something to make sure.

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[Cygnusx1]

So, any chance that this overheating fried the head gaskets? that's what happened at cylinder 6 in my old land cruiser fj80.

 

[jb56]

So, any chance that this overheating fried the head gaskets? that's what happened at cylinder 6 in my old land cruiser fj80.

As of now, the motor is working perfectly according to the dealership.

My understanding from the owners manual and everything I could find suggests that the fail-safe programming the bronco has now basically prevents any heat damage.

After the engine overheats, the cylinders alternate and act as air pumps to maintain temperature and prevent any damage. And if that failsafe stops working, the motor will just turn off. The warnings in the manual make it clear that you should be careful to drive it hot, not because it will fry the motor, but because you might have sudden power loss.

 

[vrtical]

So, any chance that this overheating fried the head gaskets? that's what happened at cylinder 6 in my old land cruiser fj80.

Not with modern multilayer head gaskets and/or o-ringing. It would probably warp a head before one of these HGs failed, but with the failsafes that's not likely to happen either. What these engines need is more hoses j/k.

 

[jb56]

Interesting enough, my dealership where I bought the vehicle was nice enough to have a mechanic call me to talk through this problem. They told me the explanation of the dealership in Moab is completely impossible and they told me I should drive the vehicle for 45-60 minutes in town before I get on the highway to make sure the cooling system is working properly.

He did say that if the hose coming disconnected was the cause, it would have been as obvious as fireworks going off under my hood. We shall see.

Good times!

Despite all this it is still the second best vehicle I've ever owned (after the GT350).

 

[tchancey]

Did you eventually find out for sure what happened? Coincidentally I was in Moab a week ago & experienced the same symptoms as you. It's been at the dealer for 6 days now.

I had to add coolant 3 times but eventually it leveled out & made the drive back from Moab to Denver. It's going to be a while before I trust it on a remote trail.

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