[old grey steve]

CBS is an interesting concept, you can go many miles between oil changes meaning more time on the road lesss time in a workshop, thus saving you time/money! Right? Well long term its not the best course of action, trust me waiting for a light to come on before you carry out the next scheduled service, that was great news for the 1st owner, even beter if it was a fleet car, but as the 2nd or 3rd owner of this sort of engine catchup is a game these engine seemt olove to play. And catchup = expense.

So case in point what you are about to see is the inside of one M57N2 engine that was reported as noisy lacked power plus had done just over 100k but had been serviced.

First the lack of power. Put simply the turbo had had its day(not surprising on these engines but still a cost) but the noise now and its cause will concentrate the mind.

To us it sounded failry rattly, more so than a diesel would normally sound and if you see enough of these easy to pinpoint. To the layman its almost likea highpitched slapping noise(difficult to describe in words).

Unlike the earlier 2.0 diesel units these are a little harder to determine the exact cause of whether you've got a chain guide related issue or not(though we've had 2 of these engine with broken chains now)through simple examination so as this was looking like it was going along these lines a different approach was called for.

So here you have one removed M57N engine out of the car upside down for an examination.





Shells when examined didn't look too bad but for a car of 100k+ we'd seen better/seen worse so with this in mind on to the front. If you are wondering why we'd opted to take the sump off to look very simple.

At the front you've got the timing case cover. And when this covers removed you have decent sight of the sprockets(the sump has to come off to look at the bottom sprocket) as well as the second timing chain, yess you've got 2 timing chains here. The main chain though not 100% visible here



was a little slack (around one link) and when checked the tensioner wasn't the fittest plus felt weak plus had carbon deposits present.

When you see this sort of thing alarm bells ring. When the timing case back was checked we saw this



if you look at the above picture and cannot see the issue as such but we'll let the picture below help. Circled is actual wear where the chain had rubbed the case casting in one particular area its basically bured it away it was lovely and smooth but its still done some damage



the picture below again shows rubbing wear on another section of the case



where metal has been rubbed away by the chain making contact with the case innards the guides weren't doing their job the tensioner was indded not fulfilling its duty therefore before us lay a very sick paitent(the guides wee also fracturing-something again you cannot see in these pictures I'm afraid).

Now as stated the sump was removed as you need to get sight for one of the sprockets .

So the sump remember this has been serviced for the mileage on or around the requied CBS schedule.





thick congeled oil it it was everywhere around the sump, oil pump area the lot(now has oil always been drained using the plug or sucked out as many BMW chose to do these days?).

Removal of the rocker cover had of course taken place as again you are looking for slack chain and guide related wear and you need the cover off to check all things in this area




again cover off flipped upside down its fairly thick underneath plus oddly enough the rocker cover was weeping too

And inside the head though you may have to look fairly hard



oil wise its fairly congeled in here too. Net result was a fairly lenghy re build new chain as it was stretched slightly(less than 1 link remember)plus new guides.



Everything was cleaned up (thoroughly) re assembled new turbo fitted 3 days after we got the car in its ran like a dream.

Rule of thumb service every year or say 10K if you can afford to service more often with less mileage between services trust me do it. To avoid the above you can do no harm with regular servicing and ignore the CBS data IMO re time and mileage. Look at the service book if its stamped up to date and you see gaps in the dates between oil services get one booked To do this sort of job(with a turbo can cost the best part of £4500 with ease..And all this we strongly feel is down to poor oil, and strongly suspected contamination of the tensioner causing other compoent issues.

[rhysh1990]

Good write up, certainly an eye opener and a real insight to the results of CBS

[Aragorn30d]

I've always given my cars 5k oil changes. You can buy a 20L drum of oil from ECP or even the dealer for about 50quid, cheap thing to change the oil and filter every 5k. Its a bloody disgrace what the dealers charge for an oil change, and its no surprise that folk dont change the oil when they think it costs 2-300quid!

My engines on 145k, and i can only imagine what it must be like inside after years of long-life servicing. I've had it since 138k and already changed the oil twice.

The chains on these engines do give me the willies. At least a belt gets inspected and changed semi-regularly. The chains get ignored until they explode.

[Ess]

Wow. I already do an annual service but may have to consider more often after seeing this. Thanks for the insight as always Steve!

[IanS100]

Does oil bought in a drum have a shelf life?

[Aragorn30d]

Probably, but it'll be many years.

[paulf61]

An interesting read and eye opener, thanks Steve!

Paul

[Dann]

Brilliant write up.
I'll always get my cars serviced at least once a year and will continue to (if not 6 months)
For as little as £45 you can have the oil and filter changed.
That's less than most people pay a month for a phone contract.

[AzRiz]

Daaaaaamn! That is horrific!

Goes to show that the manufacturers definitely do NOT care about engine health in the long run (or any aspect of the car, for that matter, with 'sealed for life' transmission claims) and have greatly reduced service frequency to look like better value and also increase profits as cars will enter the workshop less often but with a longer list of jobs to do.

Pathetic ethic...

[PJJD]

Holy crap!

As the guys above have said, oil should be changed at least every 10k miles, or once a year, depending which comes first. Personally I change mine every 7/8000 miles. For the price of a drum of oil and an oil filter, it doesn't make sense not to change it regularly.

Steve, with regard to the timing chain, do you think the problems are caused by the oil not being changed regularly enough? Or is it just a fault with the chain itself?

[Ao1]

From what I have heard condition based servicing is all about keeping costs to the minimum for fleet managers, who only want to spend the least amount possible and don’t care what happens after three years because the car is sold on.

Steve, sorry if this is a silly question buy why does engine oil get so dirty and congealed in comparison to gear box oil that is changed far less frequently, if at all?

[Ess]

Originally Posted by Ao1

Steve, sorry if this is a silly question buy why does engine oil get so dirty and congealed in comparison to gear box oil that is changed far less frequently, if at all?

I'd love to know too.

[Aragorn30d]

Because of the combustion process. A portion of the combustion gas blows past the piston rings and down into the crankcase, where it mixes into the engine oil.

[Ess]

Originally Posted by Aragorn30d

Because of the combustion process. A portion of the combustion gas blows past the piston rings and down into the crankcase, where it mixes into the engine oil.

Thanks!

[Ao1]

Originally Posted by Aragorn30d

Because of the combustion process. A portion of the combustion gas blows past the piston rings and down into the crankcase, where it mixes into the engine oil.

But isn’t the amount of pressure blow back abnormal to cause the extent of contamination that Steve has been showing us? Its effecting even low mileage cars. How can this be normal?

[Ao1]

Also is an oil change going to get rid of all that sludge build up?

[Aragorn30d]

Its entirely normal. Engine oil on a diesel goes black within a few thousand miles (or less!) due to the contamination from the combustion process. The oils designed to contain that contamination, but when it builds up to high levels, it begins to form deposits.

If the oils changed regularly, theres no chance for it to build up. But when intervals are stretched out to 20k+ it all starts getting a bit shit. Now ofcourse, the engine in question might well have missed a service or something at some point.

The other issue is garages sometimes use the wrong oil. Stick a low quality oil in there and try to run it for 20k and it'll wreak all sorts of havok. The same low quality oil on a sensible interval however would likely be completely fine.

My other car is a 2000 model 1.8T A4, and those were some of the first VAG models to get the long-life servicing. Many have died due to oil starvation, because the combination of combination of a turbocharger giving the oil a hard time, long life intervals, and garages often using the old spec oil, resulted in the oil turning to sludge and blocking the pickup. Fairly regularly you'd see posts on the forum about people getting the oil pressure warning light and wondering what to do to fix it, usually too late at that point.

[Aragorn30d]

Originally Posted by Ao1

Also is an oil change going to get rid of all that sludge build up?

Not entirely no.

But regular changes will get rid of some of it, as clean hot oil will dissolve some of the gunk away. You can also get a special oil flush products which help shift the crap.

When by brother bought his 320d, it was on 180k with a slightly dubious service history. So we did 3 oil changes back to back with a few hundred miles between them, to clean out as much of it as possible. The first oil change the new oil went black immediately, but by the third change it was much better.

[chrissyw]

So basically anybody who goes by the standard BMW 20,000 mile service schedule has an engine like that?

Shocking really.

[chrissyw]

Originally Posted by Aragorn30d

Not entirely no.

But regular changes will get rid of some of it, as clean hot oil will dissolve some of the gunk away. You can also get a special oil flush products which help shift the crap.

When by brother bought his 320d, it was on 180k with a slightly dubious service history. So we did 3 oil changes back to back with a few hundred miles between them, to clean out as much of it as possible. The first oil change the new oil went black immediately, but by the third change it was much better.

What does the super duper V-Power clean up then? Injectors, Fuel rail etc?

[AWSAWS]

Detergents in fuel will clean anywhere the fuel goes. Fuel rails, injectors, cylinders and piston heads. I assume the detergent is burnt so after that stage it does nothing.

That black sludge is scary. My brother's M5 had to be opened up to find an engine vibration and the guys said it also had lots of sludge. It has been serviced when needed and even serviced in between.

I might start doing oil changes myself now in between.

[Dann]

It will be worse in diesel engine than petrol too, petrols burns fairly cleanly compared to a derv.

My 335i has 57k on and the oil changes are between 10k and 15k on it. When I took the valve cover off it was spotless.
Oil changes every 12 months on a petrol will be fine unless you do silly miles.

FWIW go to National tyres for cheap oil changes. Oil (5w-30 LL04) and filter done for £42.15 and 30mins of your time. No crawling around on the floor or hassle of buying/disposing of waste oil.