XSeries-forum

Would like some advice regarding 'Oil Additives' in my E53 Diesel engine,i have been using either STP or Wynn's oil additives in car engines both diesel and petrol for many many years and of course one has got too use the appropriate type for your specific engine ie make sure you have the diesel version for diesel engines as they do make 2 versions.

I used STP in my old 2.8 Isuzu Trooper for over 15 years and when i sold it with 200,000 miles on the clock the engine was still as sweet as a nut,but as BMW E53 engines are far more sophisticated than anything else that i have had before i dont want to damage the engine in anyway if its not advisable to use the stuff in this engine.

So i thought i would ask first rather than find out for some reason its not advisable to use it,so my question is is it safe to use either STP or Wynns oil additive in these engines,mine is of course the 3.0 turbo diesel option,which is running just like a mechanical swiss watch  without doubt the sweetest engine that i have ever owned in 40 years of driving.

Any advice would be most welcome.

The BMW E53 3.0 Diesel is a "tight" engine, compared to the bones Ford used to make that needed additives to hold oil pressure....

The E53 Diesel will not like thick cold oil, hence using 5w/30  or  0w/30 specialist Oil.
The synthetic stuff recommended is Mobil-1 Fully Synthetic about £45 a gallon & does the job perfectly.

many of these additives will simply empty your wallet more rapidly & thicken the oil when cold.... when the engine needs oil the most.... so it's not helpful at all.

the 5w/30 means the viscosity is 5 when cold & thickens to 30 when hot... this allows the oil to RAPIDLY get where it needs to be when cold & 1st started.... ie valves, turbo charger, cam bearings, piston liner walls, bearing journals etc....

The quality of the recommended oil Mobil-1 Fully Synthetic is perfect for this, and additives will simply ruin the process.
If your engine rattles like a bitch & is generally clunky... then some additives may help & keep the oil pressure higher, but if she runs well currently, you are more likely to ruin her & starve the sensitive parts of oil on start-up due to the oil being too thick & slow to travel rapidly thru the engine galleries to the remote parts... ie turbo & cam shafts etc.

Most additives come out of their can like treacle & by default will make the oil arrival speed slower when DESPERATELY needed FASTER.

Personally speaking.... save your money & just change the oil & filters every 10k miles & all will be well.
My D-Sport has 175,000 miles on the clock & she purrs nicely... & I drive her VERY HARD.

1-Good oils
2-gentle warm-ups
3-tick-over for 20 seconds to lube the turbo as it slows down before switching off the engine.

Well said Grant , i do all that ..  1 2 3  thing , 133,000 now and as you say  purrs nicely
But i drive more calmly ..most of the time

Thanks gents for your indepth words of wisdom,glad i asked the question,the X5 is all tanked up ready for a long trip down to devon for the week,early start so we dont get stuck in the rush hour traffic.

A good long journey should blow the cobwebs out,the engine has no rattles or noises what so ever,next service is due in about 4 months time as it had a full one a week before we picked it up.

Once again many thanks 

You are most welcome Sire,

there are a few little preventative jobs worth doing & checking out on these hefty machines...
Check the diffs & transfer box oil levels & also look out for any wet areas around output shafts hinting at a leak.

get an EGR Blanker & bypass kit fitted for a few more HP & a tad better MPG & cleaner running.

As per a recommendation to me a while back from X5 D-Sport chappy, check & ensure you have a Swirl type oil seperator fitted... especially as she has some miles on her now.... this seperator device centrifuges oil from the crank case breather & ensures the engine does NOT do a runaway on oil & blow up..

Inspect the rad Header/filler area for splits or weeps given away by a whitish chalky deposit...

An odd one worth prodding at one day.... the crank pulley....
This bloody thing failed on me last year... the crank pulley is a 2 part item, that is a steel inner that splines on to the crank shaft on the front of the engine... but the belt pulley is a separate piece & is moulded to the inner part with a rubber doughnut... I believe it was due to the crank end shearing off due to vibration in the early days of X5's... and the center doughnut is known to soften & break up... at 130k miles, it is possibly due to fail some time soon...

As they say... Prevention is better than cure... especially by the road side on a hot sticky Bank Holiday.
the repair costs of these machines can be drastically reduced by regular checks, & it is easier to replace some thing at your leisure, than when disaster strikes.