The other day about 6 km from home on flat ground at a red light steam started coming from under the hood. I pulled over shut it down opened the hood. The steam was coming from under the engine cover directly below the power steering pump return line. After about 40 seconds it quit. I had it towed home removed the engine cover and only see a coolant line connected to the oil cooler. I pressured the system to 17 psi and no leaks.

Would anyone know where the pressure relief valve is the reservoir cap is a solid cap.

__________________
92 e300d2.5t
01 e320
05 cdi
85 chev c10