I use 5w40 full synthetic and have no problems doing 7k mile change intervals and it hlpes with the valve stem seal issue that our N62's have. as for the coolant... only use the BMW blue and I would suggest looking into the lower bar rated cap. I feel it is the secret to not having to add coolant and will help prevent doing the dreaded bimmerpipe fix ;)

i picked up oil, filter and coolant from the dealer.
is it common for the e53s to burn/leak/run low on coolant? :(

You have an N62.. look up bimmerpipe and you can read all about it.

just one of the "features" of our great sounding V8's ;)

Oh great.
How does one diagnose this?

Jees, had the car for 3 weeks and am already contemplating selling it:rolleyes:

Only when it needs a new head gasket.

How much coolant and oil has it lost since you bought it and how many miles have you put on it in that time?

I know this is going to sound silly, but I didnt' check the coolant when I bought it and started driving it on Aug 30 :rolleyes:
I will top it up today and write down the kms and keep an eye on it.
It's got 94500kms or so right now

Well in that case just top it all off and check it in a few thousand KMs.

Any info to support this?

For the record, You should use distilled water to mix your coolant, which only have very minute mineral content, if any at all.

No I don't. Maybe minerals was the wrong word. Phosphate I believe is what I was getting at. European coolants are engineered with no phosphates because of their hard water. I'm not a chemist by any means and I wish I could explain better. BMW did not come to the USA to engineer their coolant, they used their typical water supply like everyone else. Their claim for using this particular coolant is based on the possibility of deposits not corrosion. I'm not saying don't use it, just thought I would broaden the horizon and give another option:)