Ya it contains lower amount but is such small place it could be dangerous .... So you shouldnt give advice like that Turtle
While diesel emissions could certainly generate lethal ambient concentrations of carbon monoxide given a sufficient amount of time in an enclosed space and under suitable environmental conditions, it's virtually impossible to find such conditions in a Sprinter, especially a moving one.
European engineers, especially German ones at Mercedes, are anal about airflow. Even with the recirculation door closed and all of the vents closed off, a high pressure area at the base of the windshield draws air into the cabin and is exited through low pressure vents in the doors, body and the rear of the van. The air is so carefully regulated in MB vehicles that you probably won't even notice a draft, but it is engineered and tested to remove exhaust that's directed entirely into the cabin. You would have to purposefully alter the high pressure intake and the low pressure output in order to create a non-ventilated, "enclosed space" in a Sprinter. Even a sealed bulkhead won't eliminate the low pressure output created by the high pressure intake at the base of the windshield.
I still recommend a CO detecor in a diesel vehicle, for all the reasons described in this article.
Expedite Now Trucking Magazine - Carbon Monoxide Can Kill You
In any case, unless your "sleepy" is accompanied by headache, nausea, and dizziness, it's probably not carbon monoxide.
but been lazy I think I will take to dealer...
