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Posted (edited)

If anyone wants an illustration of why you should TOTALLY IGNORE manufacturers recommended oil change intervals(sometimes up to 20000 mile intervals!!) and stick with a 5000-7000 mile oil change then here it is!

This is the totally shafted turbo from my nissan Qashqai, according to the mechanic working on it, judging from how solid the blockage is, the worst of this was caused during the first 5 years of the vehicles life with poor servicing and probably never getting a decent run uo a motorway to clear it out.

I've had it for 3 years and serviced it regularly but last year I noticed I would get a wee tad of smoke every now and then, it got progressively worse and I knew eventually the turbo was on its knees so it's in for repair now that I could afford it. This wee pic is from the exhaust side of the turbo.

 

 

20210521_144912.jpg

Edited by Rob85
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  • Rob85 changed the title to Oil change intervals

I change my oil for quality oil every 5.000 miles. Having said this when the factory I worked at was closing I was given an ex reps petrol Honda Civic to use commuting between Notts and Wales. On checking the car over I found the oil was just a thick blob on the end of the dipstick. It transpired that the rep had his wifes and his other car serviced in place of his. Ended up discovering that the car had not had an oil change in 100,000 miles,  topped up obviously and brakes renewed but no oil change. Car went into main agent for a major service and I used it for several months. Car sang like a bird. This was 20 years ago so probably no turbo.

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Whilst agreeing with the sentiments about oil changes - I don't see why lack of oil changes should 'coke up' the turbo?  I can understand short runs, not getting fully up to temperature causing it - and I have heard that turbos should be allowed to idle for a few minutes (or at least a short period of gentle use) after a hard run to allow them to cool a bit as the oil can coke in the bearing due to the heat remaining at switch off.  Turbos get blisteringly hot when the engine is working hard and a high volume of hot exhaust is whistling through.

I always allow a short idle period when pulliong into a motorway services after a long run at speed, but usually the drive up the small lanes to home would be enough when returning to home.

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15 hours ago, JohnfromUK said:

Whilst agreeing with the sentiments about oil changes - I don't see why lack of oil changes should 'coke up' the turbo?  I can understand short runs, not getting fully up to temperature causing it - and I have heard that turbos should be allowed to idle for a few minutes (or at least a short period of gentle use) after a hard run to allow them to cool a bit as the oil can coke in the bearing due to the heat remaining at switch off.  Turbos get blisteringly hot when the engine is working hard and a high volume of hot exhaust is whistling through.

I always allow a short idle period when pulliong into a motorway services after a long run at speed, but usually the drive up the small lanes to home would be enough when returning to home.

The turbo bearing is lubricated via your engine oil, look at what happens to the engine itself when the oil doesn't get changed as often as it should.

It tends to hurt the turbo even quicker as it spins much faster on its bearing, so that bearing will wear much quicker and it's much smaller than a cars big end. Once you start to get a tiny bit of a leak from wear on the bearing the oil can leak past into the turbo where it can go down into the intake side along with the charged air into the cylinders.... if that happens you will usually get blue smoke of burning oil/overfueling, the danger with this scenario is if the bearing/seal totally gives way the turbo can run off on its own and drink your engine dry of oil and then it's a new engine required. Or it can leak into the exhaust side where you tend to get a grey smoke with a blue tinge to it and then the carbon build up as you see in the picture as the carbon particles from recirculated exhaust gases and crank case venting that will be suspended in the oil will be baked onto the surface as the oil burns off.

Bit of a ramble there but it kind of explains why that build up happened.

 

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17 minutes ago, Rob85 said:

Bit of a ramble there but it kind of explains why that build up happened.

Thanks for the explanation, which makes perfect sense.

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2 hours ago, snow white said:

I change mine every 6 months first one on mot then six months later 

I picked my car up from the mechanic tonight and he was telling me that dealerships have gone down the road of programming the cars computer with different oil change intervals depending on the customer. For example if it's just a private car then they can get the standard service interval in the book, but fleet customers often get the cars programmed to bring up the service light at a much longer interval, ensures the car is a wreck after 5 years and then they buy a new fleet.

My mechanic has a few regular customers who do very little mileage but want to keep their car in good shape, so to make sure their car gets an oil change at least once a year he reprograms the diagnostics to bring up the service light for an oil change at less than half of the manufacturers recommend interval.

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i change at 5k   old mazda b series at 228000   dont use oil or water   if or when it goes wrong i dont know what to replace it with           i dont care about the yellow vanity badge  it costs money nothing to do with reliability    oli is the cheapest part of any engine / gearbox / back axle   if you own it change filters and fluids regularly 

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How much does the quality of oil help? I thought a quality fully synthetic oil could be left for much longer?

And I assume it's the miles the oil has done rather than age that's most important? My new car has a two year / 40,000 oil change service schedule. As I'm only likely to do 6,000 miles in those two years I doubt it's worth changing the oil any sooner?

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34 minutes ago, Windswept said:

How much does the quality of oil help? I thought a quality fully synthetic oil could be left for much longer?

And I assume it's the miles the oil has done rather than age that's most important? My new car has a two year / 40,000 oil change service schedule. As I'm only likely to do 6,000 miles in those two years I doubt it's worth changing the oil any sooner?

40,000 mile oil change??? That is absolutely crazy in my opinion. That will destroy your engine without a doubt. One of the cases a former car mechanic who works in my place was telling me about was a vauxhall astra that had done 51,000 from new and had one oil change. Big end bearings were destroyed completely.

Age doesn't matter so much when oil is in a nice clean tub on the shelf but when you put that oil in your car and it mixes with carbon deposits and all the usual stuff found in a crank case then age does play a big factor. Also bear in mind that when you leave your car for an extended period without use the oil will drain to the sump and the engine has to circulate it on start up.

Other opinions may vary but some of the advice I have heard recently is that fully synthetic oils that have a 0 on the front like 0w45 etc aren't the best idea for turbo diesel vehicles as the oil is that thin it's quite easy to push past the bearings and piston rings under load leading to oil being burnt.

As regards quality of oil, most oil is well up to scratch these days but I stick with a reasonable quality semi synthetic for my vehicles. To err on the side of caution, even if you do low mileage, service once a year....coming into winter is a good time for it.

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It's actually 36,000 miles for my Dacia. This is the same as new Renaults, oil is only changed every other service and the service interval is 18,000 miles or yearly.

Mines a small turbo petrol engine but I think the Diesels are the same.

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1 hour ago, Windswept said:

It's actually 36,000 miles for my Dacia. This is the same as new Renaults, oil is only changed every other service and the service interval is 18,000 miles or yearly.

Mines a small turbo petrol engine but I think the Diesels are the same.

Those small capacity petrol turbo engines are working hard  to produce enough power to move that 1.5 tonne vehicle around.

Do yourself a favour and ignore that service interval, oil and filter at least every 10000 miles.

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5 hours ago, Windswept said:

It's actually 36,000 miles for my Dacia. This is the same as new Renaults, oil is only changed every other service and the service interval is 18,000 miles or yearly.

Mines a small turbo petrol engine but I think the Diesels are the same.

The dacia engines are pretty much the same as the engines in a nissan qashqai, the 1.5dci diesel is the renault K9K series engine, dates back to the early 2000s as far as I know.

That oil change interval is designed to wreck your car over 3 to 5 years so you come back and buy another new car

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On 24/05/2021 at 13:22, matone said:

The extended service intervals are just to make new cars sound cheap to service and makers have no interest in later life reliability.

Possibly not quite true, they love the provision of spare parts and repairs at a huge markup?

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I change the oil and filters in my car engines every 5000 miles . Both Honda cam chain engines , 1.4 petrol and 2.2Turbo Diesel .

300,000 miles between them , and they still run like swiss watches. I always let the TD , tick over for 30 seconds at least before I turn it off.

12000 Miles service intervals are a nonsense.

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Posted (edited)
17 hours ago, Rewulf said:

Those small capacity petrol turbo engines are working hard  to produce enough power to move that 1.5 tonne vehicle around.

Do yourself a favour and ignore that service interval, oil and filter at least every 10000 miles.

Very good advice ! The intervals some are describing make a mockery of `full service history` in adverts for used vehicles ......

Edited by matone
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8 hours ago, Longbower said:

12000 Miles service intervals are a nonsense.

12,000 mile oil changes are very common though and there's plenty of engines with 100,000 miles on them.

I wouldn't wait 36,000 miles but I'd be happy with 12,000.

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Do people not regularly dip the oil with the dipstick?

You can tell an awful lot from the small amount that is deposited on a clean white cloth.

I was brought up on Fords and Vauxhalls and the only way to lengthen the engine life was to keep the oil clean and relatively fresh.

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Service interval on my petrol non turbo Mazda is 12,500 miles and at 65K it never needs a top up and the oil stays fairly clean on the dipstick. Interestingly the exact same car sold in America has a service interval of 5K miles. How does that work?

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Looking at that crud build up I’d think it was more related to the egr system as that looks like a build up of sooty deposits not burnt oil.  If the turbo intake looks like that I dread to think what the egr setup looks like. 

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