Immediately after starting the car their is a smell of exhaust through the vents. After that there's no smell... How could this be?

Check the rubber seal on the shelf below the windshield, engine side. The soft rubber might be deformed and no longer sealing the engine from the cabin air intake. Use some vinyl protectant on the seal to keep it flexible and clean.

Klaus
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Volvoless. Sold the R. There is now a void...

Klaus it looks in good shape, how can I verify I'm getting a good seal?

Check the underside of the hood and see if it leaves an impression all the way across.

Klaus
--
Volvoless. Sold the R. There is now a void...

I had a problem when I would start the car or when sitting at a redlight with the air running I would get an engine smell. When the car was moving, it did not happen or if I was on recirulated air. My problem was the hose that goes to the flame trap had basicly colapsed/clogged. Flame trap was clean. Replaced those hoses and problem went away.

Keith

96 850 325K, 2001 V70 110k and timing issue driving me crazy right now.

Thought that was my problem also. Changed all hoses and Oil Trap in the Breather system. It seems like it may be better, but still there. This is a brand new addition to me so I'm not sure how long it's been there or when it started...

When installing a new Cabin Filter, I noticed some weather stripping peaking out from the "underside" of the cowl giving way to about a 1/4" gap straight into the Ventilation area from the engine compartment, hence my "Smell".....

Once I installed the retainer/filter I glued the weather strip back in place and the exhaust smell when first starting the engine appears to be better.