Sudden lose of all coolant on to road. Milky substance on dipstick

Hi guys out driving. Suddenly all coolant pissed out the bottom of the car. Still driving fine. Coolant tank now empty with weird milky liquid in. Dipstick showing milky residue to. No signs of over heating before or after. Driving fine but only drove home few miles after coolant leaked out. Any ideas on what could be? Suspect head gasket but would that make coolant just suddenly dump out on road and would there not be more warning with say over heating. Advice appreciated

A cooling system leak caused the coolant to leak on the ground, the head gasket failure occurred next.

One mile of driving without coolant is enough to damage the engine.


Milky residue on dipstick hints at an internal head gasket leak, letting coolant mix with the oil. Sudden loss of coolant onto road is a different leak - head gasket external or radiator or coolant hose or…


The engine is likely toasted now. There are a few tests to determine that.

That being said, if you had pulled over and stopped instantly when this happened the engine would not be toasted. Same goes for the red oil pressure (or lack of) light. It means stop now; not a mile or so down the road.

With no coolant in the engine the temperature sensor would not be submerged in hot coolant so that is likely why the temp gauge was not showing it to be overheating. Assuming of course the temp gauge was not being overlooked.


Milky oil and coolant means the oil and coolant mixed. Milky oil is not a good lubricant and will wear out your engine faster, but depending on how long you drove in this condition, the engine maybe OK, though it wont last as long as it would have if this didn’t happen.

Most likely a blown head gasket. The exhaust gasses getting into the coolant can build up enough pressure to blow coolant out the radiator cap and it can be sudden. A new head gasket should take care of it.

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Just what is this mystery vehicle?



model year

Which engine

It doesn’t matter by now, does it? It’s a dead vehicle.

I still want to know

As for “dead vehicle” . . . depending on just how bad things are, it may be possible to save the engine

I’ve seen some cars with blown intake gaskets pouring coolant into the crankcase soldier on for years of reliable service, after the necessary repairs are performed

And those vehicles I’m thinking of never stopped running and never overheated before the repairs

I’m surprised you’re so pessimistic

That’s usually my role :smiley: