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Engine Coolant leakage - On a truck to the garage

Performed an oil change yesterday and the worker informed the I had a coolant leakage. Said it should be OK to drive home (20 min drive).
At home there was almost no coolant left in the reservoir. Going to the repair shop...:(

Will give update on repair.



These hoses come from the thermostat,
It is a set of 4 hoses with a steel tube coupler in the middle.
The housing of the thermostat is made from plastic maybe there is a crack in it or you have a perforated hose.
I don't think this is comming from the oil cooler, water usally leak down, not up.
It's correct that the hose is pulled back a little.
But on the end of that pipe there is a little collar to prevent the hose sliding of.

Taking a better look at the first photo I think the is a minor crack in the oil cooler were the pipes go in,
hot coolant will give pressure and looking at the traces of coolant loss it is just spraying around.

The way your mechanic is handling this is a bit strange, he is servicing your car and sent you home with a coolant leak
He had to discuss this with his supervisor and had to repair this imidiate.
But that's my opinion.
Thanks for all feedback and suggestions.

Just to be fair to Hyundai, my oil change was done at a non-Hyundai workshop.
The leak was just discovered by happenchance during oil change. They do not to warranty repairs there. Have to be done by a Hyundai authorized shop.
Sorry to hear this, @Mightymoo. I hope they get it sorted out for you quickly.

Spray is up under pressure, leak is down. The coolant from around the oil cooler, under the oil filter is an accumulation. The spray from under the bonnet is under pressure and near where the leak originated.

The hose on the oil cooler is fine, as it doesn't pass the splayed flange end. The leak didn't occur from this location. The coolant chose the path downward thru this area. The lines on the oil cooler only circulate oil, not radiator/coolant fluid.

No cracks in the cooler either as you'd see oil leakage. Note the openings inside/outside the filter o-ring, OIL ONLY. One set of holes is; for oil return the other oil evacuation.

From the location of the oil cooler on the engine, there is no way for the coolant to spray the underside of the bonnet, in this location. The leak didn't originate from the oil cooler area but above and coolant ran down, taking the easiest channeled route.

If it were me, I'd be looking at the; radiator cap, pressure cap on the overflow reservoir, thermostat housing and upper radiator hose. It might even be a leak in the seam of the plastic, reservoir. The tank is plastic molded in two pieces, a seam runs around the entire tank. They're known to crack when defectively molded.

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"The lines on the oil cooler only circulate oil, not radiator/coolant fluid. "

I can assure you these are not oil lines.
Oil is running on the inside through some laminated layers just like a radiator.
The coolant is running around the oil in a seperated chamber.

You're right to check everything especially the plastic parts as mentioned.

The garage has to be able to pressure test the system without running the engine.
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Outstanding @Mightmoo

@ red dutch and Mightymoo; Sorry, I'm wrong about the oil cooler for the i30N. I was thinking about the Elantra with both the oil/trans/cooler. It utilizes a similar setup that circulates oil thru the lower part of the radiator, which is not part of the cooling system. My bad! Learn some thing new everyday.