I've had a leaking head gasket for some time on my 1992 300E (with 103.983 engine), eating a bit of oil and oil on the garage floor.

While on a trip the upper radiator hose sprung a leak. I chopped and shortened it to temporarily fix it, and in doing so noticed the coolant seemed "muddy". Further investigation showed oil in the coolant -- a bubbly syrupy mess in the coolant tank.

I took it to the city's MB dealer who diagnosed it as a blown head gasket. So... $1750 later I had a new head gasket and upper/lower radiator hoses, a new coolant tank, and resumed my trip.

I checked the coolant after a couple hundred miles and it seemed ok upon casual inspection. Also the oil leak seemed to have stopped.

But... today I had the hood up after driving (engine still hot) and noticed the upper radiator hose was collapsed on itself. The lower radiator hose was also slightly collapsed. Opening the coolant tank cap allowed air to audibly rush in and re-expand the hose.

And... the coolant was the dreaded chocolate milk color again. Aaaagh. The coolant does not appear to be as gooey as it was before, but that may just be a matter of time.

Before I take it back in for service, I'm hoping for some wisdom from the forum about what is going on here.

Is vacuum in the cooling system normal after running the car, and the hose collapse is due to softening from oil?

Is what I am seeing in the coolant (see photo below) in fact oil, and is a blown head gasket the only thing that could cause oil in the coolant?

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1992 300E Sedan (Sold)
1999 E320 Wagon (Sold)
1995 E320 Sedan
1995 E320 Wagon