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The manual for my 2003 VW TDI says to change the oil every 12 months or 10,000 miles. My dealer says every 6 months or 5,000 miles.

Are they just trying to make twice as much money off my oil changes, or is there a legitimate reason to change the oil twice as often as VW originally printed in the book?

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5 Answers 5

To a certain extent it depends on the type of usage you do, but for an average driver doing average miles (i.e. a mixture of highway, country and urban driving), I'd say to stick with the manufacturer's recommendation - but make sure you also stick to the recommended specification of oil.

Remember that oil technologies and manufacturing tolerances have improved massively over the last 20 years or so, meaning that services don't need to be as frequent as they used to.

Personally, I wouldn't take a car of that age to a main dealer, once it's got the the age when keeping a full service history is no longer important, I'd go with a small independant or do it myself...

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I think it depends what type of oil you use. Synthetic can go longer between changes because it doesn't have viscosity modifiers that breakdown. For instance 5w-30 dyno oil is actually 5w oil with viscosity modifiers to make it act like 30 when hot. As the oil is churned about inside the engine, the modifiers break down until you're left with 5w oil that acts like 5w oil when hot (not good). Synthetic oil is different. The base stock of the oil is 5w-30 and doesn't break down to 5w with use, so you can go much longer between changes.

Synthetic oils are a whole different story. There is no VI improver added so there is nothing to wear out. The actual oil molecules never wear out. You could almost use the same oil forever. The problem is that there are other additives and they do get used up. I suppose if there was a good way to keep oil clean you could just add a can of additives every 6 months and just change the filter, never changing the oil.

http://www.bobistheoilguy.com/motor-oil-102/

I have seen several car owner manuals that are now stating that oils do not need to be changed but every 7,500 miles or more. The same manual also states OR every 12 months, whichever occurs first. My feeling is that you can probably go 5,000 miles on the average (in a sports car) but you must change your oil in the spring time at a minimum, particularly up north. Oils form waxes in icy cold weather. There is a permanent thickening of the oil.

Some automotive manufacturers are backing down on oil change intervals to 5,000 miles or less and some advocate changing the oil at least every 6 months as well. I think this is because of the tendency for oils to thicken in very hot engines (not ambient conditions, just hot engines). Also because of thickening from the cold of winter and from sludge build up that cannot be filtered out.

http://www.bobistheoilguy.com/motor-oil-104/

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TDIs only take synthetic. –  Ken Aug 13 '13 at 17:08
    
I don't know... I'm pretty sure I could get some dino oil to go in the hole –  Randy Aug 13 '13 at 23:17
    
@Ken, if manufacturer require synthetic, and specifies 10 000 mile interval — this is all you need to know. Well, you also need to know if the mechanic is going to put synthetic in as well, and that they not just giving you general recommendation based on conventional oil usage. As mentioned in other answers, if the car is not subject to frequent heavier operation (towing, excessive hill climbing, a lot of stop-and-go traffic etc.), the normal service interval is good enough. –  theUg Aug 15 '13 at 5:10

Not every dealer is trying to squeeze you for every cent they can although some certainly are. Giving the dealer the benefit of the doubt, ask them why they think you should change it more often. It is possible they are looking at the miles you drive compared to the average and assuming you drive short trips which are particularly tough on diesels and need to change oil more frequently or that your oil looks especially dirty. If they can,t give you answer then follow the recommended guideline. Make sure you check the oil level regularly.

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I would do the oil change every 7500 miles. A TDI is a very technical engine and with the turbo I would use only fully synthetic 5w30. I’m on a 7.5k interval and am hitting 200k miles on an 05 and it has always pulled very well. On original internals also.

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What was your basis for this number? Was there a VW service bulletin that changed the recommended oil change interval for this engine? Or did your mechanic suggest it? Or did you just think "I'll do it 25% sooner than the book says, to be on the safe side"? –  Ken Sep 3 '13 at 0:09

I change the oil every 18,000 miles. My tdi is on longlife service plan and I use only the best long life oil.

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