I am due for an OSV replacement. I already have it. It produces a high pitch tone, very loudly when the engine is hot. Since my coolant level is very slowly decreasing, I suspect I have leaky valley pan gasket as well (as I see not other evidence of leaking hoses or gaskets). So, I am thinking that I should press on, and replace all these items in one session. A two day session that must be! That also allows me to slack the B+ cable with the intake removed and have an easy time with the driver side valve cover gaskets. These X5's all have the same issues...... pretty predictable when you read the posts.