Just changed the oil in the Passat myself, for the first time. Holy crap, the stuff was like black paint. Smelled like charcoal!

It’s on variable service intervals and gets mostly motorway driving so I generally get over 15k miles before the service reminder comes on. I probably went 800 miles with the reminder on, and I wouldn’t have expected the oil to be this bad.

The service was last done at a cheap but friendly and quick branch of a chain – too cheap, perhaps? Either the oil they used was crap or they maybe ‘forgot’ to change it last time?

Should I expect a turbo diesel to always do this to its oil?

It’s a diesel, chances are if you give the oil another change a day later it would still be as black, don’t worry about it 8)

Brothers PD TDI oil always comes out filthy. Guess it’s just the nature of TDIs

Personally, I wouldn’t leave 15K between oil and filter changes on a turbo diesel, I do mine at 6 ish

It’s a turbo diesel, the oil goes black as soon as it goes in IME.

15K is a bit long for oil if you ask me regardless of service intervals. Though my Almera survived for 7 years without one, and the engine wasn’t the failing part 🙂

In the States there are drive in oil and filter change shops, could do with those here – get it done whilst you’re shopping, at a cheap enough price to just do it every 6 months. Doing it at home is a hassle to dispose of the waste oil properly.

Fair enough.

The engine has sensors to monitor oil quality and duty cycle, so if you are doing lots of long motorway trips for example the oil lasts a lot longer.

In the States there are drive in oil and filter change shops

Yes but that’s because the manufacturers specify (and people supply) semi-synth oil and tell you to change it every 5k miles. Which can easily be used up in 3 months. We hired a car to do a long roadtrip – nice and new, only 3.5k miles on the clock. One drive across the continent and it needed an oil change en-route! Had to sit and wait for four hours in a random town in the middle of the plains whilst they found the right oil filter!

Also, oil change seems to be the only thing they do – dealers or garages don’t give you reminders and scheduled services like they do here (as far as I know, anyway – met with blank looks whenever I’ve discussed it), and most states don’t have MOTs either! They’re bonkers at times.

I changed from 10k service intervals (recommended for my car) to 15k intervals (VAG 1.9 PD TDi), as at the time I was going about 32k miles/yr and 3 services on top of all the other costs were starting to mount up.

I figured for the mainly steady speed A-road/motorway journies I do, the engine should cope.

Can’t remember how long I’ve been doing that, but think it’s about 100k miles. Engine still fine.

If I was doing more stop/start town driving, I would stick to the recommended interval.
And I was always told that engine oil from a diesel will come out black after no time at all…..it’ll be fine*!

*fingers crossed.

If I was doing more stop/start town driving, I would stick to the recommended interval.

If your engine supports the variable intervals and you do stop start driving it lights up after maybe 8k miles – I think the longest it’ll go is 20k miles/2 years.

Point is, it knows what kind of driving you’re doing and advises accordingly.

You only need to worry when there are bits of metal crap swirling around in it

My tuppence.

I found that if I changed the oil before it went black then the next lot stayed clear a lot longer (i.e. more than ‘no time at all’).

So my thoughts are that the oil goes black when the filter is overcome by crap and the stuff starts to form sludge. Catch it slightly before that and there’s significantly less sludge in the engine to be diluted by fresh oil (but its stil there) so the oil loosk cleaner.

Though with a diesel that would be quite tricky as you’re supposed the run the engine to warm the old oil up.

I recently changed the oil in my car for the first time in over 10 years (I have got other people to do it for me in the meantime!) – had obviously forgotten how much of a mess it makes – though last time I did it I could remove the oil filter from the top of the engine rather than having to crawl underneath for that bit. About 12k miles since the last change I think, though over a year, but mostly longish distances.

I just took it down the local tip – why is that so difficult?

That should be done on most vehicles to be fair aracer.

Hot oil is less viscous than cold so it comes out easier.

Having beena spanner monkey in a previous life, I can confirm I have NEVER seen clean Diseasel oil when servicing. This was anything from brand new VAG to old VAG cars. Always black as the ace of spades and watery!!

No dedicated sensor as such, it just keeps an eye on how you drive, the oil level at startup, oil temp and the external conditions & does a lookup in a table to determine when the service light comes on. Pretty sure if you poured a load of water into it, the “please change my oil” light’d be the last thing to come on.

It claims to know the soot content of the oil – at least, via VCDS. Not sure how it could – resistivity maybe? Or it’s just inferred.

Could be wrong, but I think it works it out from how its been driven. It’ll have soot senors to determine if the DPF needs a regen, but something to actually analyse the oil would be too expensive.

Imo the only person extended intervals benefits is the manufacturer.

By the time any damage has been done its out of warrenty , and if its doing the milage to warrent extended intervals within warenty then its doing long long trips.

Filters and decent oil for my car costs 50 quid so i just do it every 10k , takes me an hour including the time for a coffee while the old oil drains out.

As aracer says – easy enough to take it to the tip. – a propper oil catch pan is worth its weight in gold doing it on your drive over a bucket. I have an old 10litre paint tub i keep my old oil in … I mix it with cheap hammerite and paint my chassis’ before winter,

Audi 1.9tdi PD here. Was on the 20k (variable) service cycle for the first 160k then I moved to 10k. 250k now and no problems. Uses less than 1/2 a litre between services (but often none) still runs sweet.

TR, you would appreciate that lots of easy motorway driving is better on the oil, yes? So it should last longer?

This is all the variable interval does. Bear in mind it’s not EXTENDED intervals, it’s VARIABLE intervals. It will ask for a change in less than 10k miles if you do lots of short trips.

My dad & I had another theory about extended service intervals. With modern oil being so thin, by the time you get to 20k you’ve already poured at least 5 litres through the thing anyway so effectively your oil isn’t 20k old.

I think you’re missing the reason why I specify diesel (I presume oil in a petrol won’t become black the first time you run the engine) 😉

I just took it down the local tip – why is that so difficult?

My nearest tip that accepts it is is about 12 miles away. YMMV.

Castrol Edge comes out of the Prius looking the same as when it went in. Very kind to its oil that engine.

With modern oil being so thin, by the time you get to 20k you’ve already poured at least 5 litres through the thing anyway so effectively your oil isn’t 20k old.

My TDCi doesn’t use any oil between changes, certainly not a noticeable amount.

had obviously forgotten how much of a mess it makes

There’s a great place near us with rentable workshop space and lifts for £15/hour. I can get an oil change and general underbody inspection/wheel bearing push-pull test done in 45 minutes. The oil goes straight into a giant funnel-topped barrel on wheels so for another £2 they’ll get rid of the oil for you.

There’s a great place near us with rentable workshop space and lifts for £15/hour

What’s it called? I could use one of those.

molgrips – mine isn’t ‘variable’ service. Although it is the VAG 1.9 diesel. Perhaps it was only the ‘posher’ marques that got the variable servicing? Mine’s an 03 if that makes a difference.

hot_fiat – Member
My dad & I had another theory about extended service intervals. With modern oil being so thin, by the time you get to 20k you’ve already poured at least 5 litres through the thing anyway so effectively your oil isn’t 20k old.

How come?
I don’t have to top my car up at all between services. The level doesn’t noticeably change on the dip stick. And that’s with 15k service intervals. Oh, my car probably isn’t considered modern though anymore! (It’s an 03….!)
My mate’s Golf (I think it was branded the GT) with the 140 2.0 TDi used to get get through quite a bit of oil though, now you mention it. I think he used to stick in about 0.5L/1000 miles.

And my wife’s old 58 plate 308 1.6 petrol (god awful car) used to chug through oil as well. One of the reasons we got rid – low oil level warning used to come up on the info display thing about once a fortnight. It was checked at the garage a couple of times, and apparently it’s ‘normal’!

From a commercial vehicle perspective on both vans & trucks doing mileages ranging from 10,000mls per annum to 100,000mls per annum most of your early servicing info goes against everything the manufacturers says.

1) Why would it only benefit the manufacturer? Our vans have unlimited mileage warranties for 3yrs. Customers regularly use them for 2-300,000mls before warranty expires. Even lower mileage engines doing 100,000 over 3 yrs would show issues due to extended servicing if that was the case. The engines in our vans are essentially the same as in the cars.

2) The service intervals on our vans are upto 37,000mls. They dont burn litres of oil (We give 1 litre with every new van an often get it back at trade in). They can buy 3 services for £450 so its not exactly ripping people off for servicing and after 3 yrs our vehicles are worth top money…..hmmmm doesnt really fit in this does it.

3) Our vehicles measure the viscosity of the oil, the driving use of the vehicle and how many regens the vehicle has done alongside the date it was last serviced. As a lot of vehicles use the burning of fuel in the exhaust system to burn off the crap, the unspent fuel actually gets put back into the oil system so the vehicle ecu keeps a check on this to ensure you dont end up with too much fuel in the oil. Not sure how a vehicle responds when you service it and dont reset the regen count.

4) The oil is 5w30 fully synthetic oil which costs nearly as much per litre as champagne (I drink crappy champers). It is the oil companies and the manufacturers who determine wether it can cope and they have a vested interest in their reputations and reliability. Its commercial vehicles so you can just say sorry, it costs every time the vehicle has an issue.

Seriously guys, we have customers who insist on doing the old service it every 6k and they get all the same problems that the guy doing a service every 30-37,000mls gets. Moreso they are the ones that mollycoddle their vehicle and end up with more problems. The guy who uses his vehicle, does a bit of motorway driving and gets it serviced when it says it needs it usually ends up the winner over big mileages.

I dont claim to be the guy who knows the ins and outs of engines and oils. It makes sense that fresh oil does an engine more favours than old oil. However, more intelligent people than me working for manufacturers of vehicles and oil companies do say its ok to use these mega expensive oils for longer and longer periods and tbh i havent seen any worrying signs to counter this argument

molgrips – mine isn’t ‘variable’ service. Although it is the VAG 1.9 diesel. Perhaps it was only the ‘posher’ marques that got the variable servicing?

Ah, ok, my apologies then.

Anyway this is an oil thread, where’s Sui?

I always used to do all my servicing myself and always changed the oil early, motorbike gets done every 2.5-3k as opposed to recommended 4k (it does track days), cars typically every 8-9k if the manual states 20k.

In response to the ‘TheLittlestHobo’, I’d agree it’s not always necessary but I do believe it does make a difference for high performance engines or if you are running older higher mileage vehicles where the engine is running looser, so more containments will make it’s way into the oil. For example on my motorbike there is always a noticeable difference in sound and gear shifting when I change the oil and the difference is more pronounced when I extend it too long. The vehicles I run don’t get molly coddled and regularly see their redlines and even their limiters at race track speeds.

I wouldn’t recommend a granny doing 5k a year this advice, which is irrelevant anyway as the once a year service would mean it gets changed anyway.

I’ve recently switched to getting one of our cars professionally serviced using the variable schedule, up to 20k but I still oil change it myself at approx 8k. Now I use an oil extractor which makes the job much easier on a modern car. It means no need to remove a vast array of under engine panels, no mess, easy to dispose of the oil and I know my good independent garage drops the oil out of the sump properly at service time.

Oil extractors are really good but it’s worth while researching if they’re compatible with your engine as they can do a poor job on some cars. They don’t make the job faster but it’s cleaner and simpler.

The oil out of every diesel I’ve owned goes black fairly quickly.

What’s it called? I could use one of those

It’s called Ramp and Wrench.

Longlife engine oil is SUPPOSED to come out black and smelling of carbon, it means it is doing its job in keeping the engine sludge-free.

Frequency of oil changes is dictated by driving style – I used to change the engine oil in the Landy three times a year because it was only used for short drives and seldom got really hot enough to drive out condensation. I used Comma oil that I bought in a 25 litre drum and the old engine with over 250,000 miles used to tick over like a sewing machine.

Changing the oil at shorter intervals than recommended also gives me some piece of mind and for the costs involved, I’m happy not to stretch it out.
Look for deals on the oil and stock up

This year, I’ve bought ….

5 x Petronas SYNTIUM 5000 CP – 5W30 Synthetic Motor Oil – 5 L Bottle
from Amazon @£10.73 per 5Ltr bottle

30 x Castrol Power 1 Racing 4T 10W-40 – 1L bottle
from Tesco @£2.50 per 1Ltr bottle

So I can do a car or motorcycle oil & filter change with a quality product when I feel I want to do it for less than £20 all in

HELLO 8)

There are a number of sensors ion the sump that will check quality of oil and that combined with the type of driving you do. Some points to remember,

If you do short trips you will not be doing DPF regens much. DPF regens use diesel as the medium to for the burn process, if this gets interrupted (which short journeys will do), it will dump diesel back into the sump. This has a couple of effects, 1, thinning, 2 introduction of ash (black shit), 3 sludging/emulsification from bio products.

Lubricants are not all made equal (like fuel). There are two main constituents to producing lubes

1. Base oil – this comes in 5 grades, 1 to erm.. 5 1 being from a bye gone era , 5 being a fully synthetic base. Thick oil does not mean good oil – quite the opposite – a good oil will be fully synthetic with a lower starting viscosity, but will not change much under heat.
2. Additive packs – this is where the big difference is made. People like Castrol (BP), Fuchs, Chevron, Shell etc spent vast sums of money developing add packs with [other companies] to be mixed to their preferred base oils. The add packs have numerous benefits, antifoam, anti sludge, anti oxidant, emulsifiers, to name a few – Halfords own – well, good luck.

So back to the engines themselves. Some engines, especially new ones want you to use a certain type of oil, as it’s been largely designed around using it, though there will be a “standard” that it is “comfortable” with. Use the correct oils and the variable servicing is normally able to extend the service intervals depending on the points above!

There are a lot of variables to consider with oild servicing, however I would simply suggest, get to know a good friendly specialist for your car (mines a BMW and the blokes are ex master mechanics charging a 3rd of a dealership), listen to your car (as you listen to your body) and use decent oils and fuel.

So – Castrol edge worth £4 extra over Halfords?

TBH I was almost shocked to discover no goop or sludge in mine when I dropped the sump off, just lovely black gold. Which I poured all over the driveway obviously.

ooh yes.

@Sui, what do you reckon to Mobil Super? I used it last time purely because it was in spec and cheap (in Halfords funnilly enough) but I don’t know a good oil from bad tbh…

(it’s good in Lyriks too!)

Oh btw, Asda had Castrol Edge for £38, same price as Halfords’ own.

So – Castrol edge worth £4 extra over Halfords?

No. Read The Engine Oil Bible to see why regularity of oil changes is much more important and why buying a fancy brand is a waste of your money.

As long as your oil has the right industry specs there’s no reason to go for a fancy brand.

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