I have 92 400E with 165K Mi. My latest problem is when I first start the car the oil pressure reads 3 BAR and stays there at idle and driving but after the car warms up to 90C the presure drops to 0 even driving down the hwy. I search this site for this problem but I did not find the same situation. Any ideas what it may be? I found two leads; oil tubes and oil relief/check valve. But I did not see the same simptoms described in the threads.
Where should I start probing?