Mix water with oil

Hi Jonaz, is the Hyundai automatic or manual? If it's automatic, we need to determine which oil is mixing with the coolant (hydraulic or engine oil). To do this, check which one has a low level. Also, if you replaced the head gasket, did you test the cylinder head for flatness? Did the problem start before or after the gasket replacement?

The transmission is automatic and water is contaminating the engine. The cylinder head and block flatness test was done and everything was fine, as was the hydrostatic test. However, I drove it for two days and it didn't mix properly, but it consumed a liter of water in 80km. When I pressurized the radiator to check for a water leak in the cooling system, surprise, surprise, it started mixing again

Hi Jonaz, if it's engine oil, there are two possibilities for the oil and water mixing: the first is in the cylinder head, and the second is in the oil cooler. The oil cooler is usually located at the base where the oil filter screws in. You can try bypassing the water connection that runs through there, leaving the cooler exposed. If there's a leak, it will come out there, and you'll be sure that's the problem. Regarding the cylinder head, remember that these are high-compression engines and require proper torque. Incorrect torque can cause a loss of compression and mixing, or loss of fluids (water and oil). If you bypassed the cylinder head as mentioned before and there was no oil or water leak, then it's definitely the head gasket. Let me know what happens. Good luck.

If you say you pressurized the radiator and it mixed, there's a possibility the cylinder head has a crack in some hard-to-detect area, and that's where the water is leaking into the engine. When you torque the cylinder head, it expands and leaks the water.

I was thinking the same thing, but I imagine that at the machine shop they sent it a higher pressure than the 15 psi I put in