Hi all just after some advice I have a 2004 530i m sports with 150,000 km on the clock what I wanted to ask is should I do an engine flush on the car as the bottom of the oil lid is slightly gunky . What would be the best product to use

Research seafoam product. I have never used it but it is used for what you describe. Add it to oil, run engine a bit, change the oil.

And the filter!

Ok ill have a look at that I also stumbled on one called marvel mystery oil has anyone tried this

Marvel Mystery Oil is a very light weight, high detergent "oil" that's been around for a long long long time. Machinists often use it to lubricate tools and equipment. I don't ever think I've thought of using it to "flush" an engine and have had a can of it around to use on squeaky hinges and to wipe down tools and such to help prevent rust. Seafoam has a long history of use in engines - think it got it's name from use in marine engines that often sit idle for months, run in 'wet' conditions, and collect gunk.

In my experience (having run up high mileage on my cars for years in the past) is that with regular oil changes (conventional or synthetic) the accumulation of gunk in the engine internals is minimal. I've pulled the valve covers at nearly 300K miles from my '86 (ran synthetic oil with changes every 6k-9k miles) and it - and the valve train) had no visible accumulation of baked on oil or grunge.

I'm not shore if it has gunk in the motor just making an assumption thats why i figured I would ask someone on hear its just the oil lid looked ordinary so I thought it might be a good idea to maybe give the engine a good flush it could be ok .
What do u think

What kind of driving do you do? The gunk that's associated with water doesn't usually build up much unless you do a lot of short trips, and even then it's more prevalent in a colder climate than yours. You might do more good by taking it for a quick blast to Sale and back rather than flushing. I just replaced the VCG on a 330i at about the same mileage (same engine, M54B30), and everything under it was just pristine clean. But that engine has a 80 km daily commute in the Houston sub-tropical climate.

Find a high detergent oil and switch to that cause most synthetics don't have as many cleaners in them which makes them emission efficient but doesn't help against varnish build up . In the meantime I flushed with B12 chemtool Engine treatment.

Currently in the new car i am going to run Torco SP oil and do twice a year oil changes(has additives that engines need). I think they make a additive separately too. I did a thread on flushing it here somewhere

Thanks guys I do around 60 km a day and my oil changes are every 25,0000 km .I have noticed lately that I needed to add 1lt off oil I'm thinking I might have to go for the 10 w 50 oil as the kms are high

If you're adding (only) one quart between changes and your changes are every 25,000km (15,000 mi) I'd stick with the oil viscosity you're using ... that oil use is very low.

If it ain't broke - don't fix it!!