New oil question!!!

[chubert]

I recently bought a car from a non porsche dealer who said they changed the oil before delivery. I beleive them since it was perfectly clean on the dip stick. I drove it for about 500 miles like this.

I had no idea what brand or weight they put in but I would guess it was cheap and available at the time.

I went ahead and changed it to Castrol Syntec 5W40 and noticed some differences.

I now have WAY more blue smoke on cold startup.
I also notice a lot more clatter on startup after the car sits for a few days. I really had no or very little smoke on startup and with the old oil it seemed to make less noise on startup.

The positives are it seems to run a lot quieter once warmed up.

Any ideas if there is a comprimise to limit the clatter but still keep the smoothness once warm?