Oil change interval

The Show
1

On the most recent show, a caller (I think her name was Melanie) called in regarding her oil loss problems. While the hosts were absolutely correct about the situation with her car, specifically engine damage due to low oil and improper oil change intervals, they really blew it at the end. She mentioned that her husband only changes his oil in his Jetta TDI every 10,000 miles, and the hosts laughed and said he had destroyed his car.

All VW TDI engines have a factory recommended oil change interval of 10,000 miles. It is important that the correct synthetic oil is used, but 10,000 miles is the correct period for an oil change. These engines typically last well over 200,000 miles with that interval, and many last well over 300,000-350,000 before requiring an engine rebuild or starting to consume excess oil.

This situation is not unique to VW TDI’s any more. Newer cars and higher quality full synthetic oils on the market now are resulting in longer oil change intervals.

2

Perhaps the hosts were not aware that TDI was VW’s designation for Turbo Diesel which does have a recommended oil change interval of 10,000 miles (with the use of synthetic oil).

3

Yes I’m sure they were not aware, just wanted to point it out to them since this is not the first time they’ve expressed ignorance of TDI’s.

It is not just an issue of TDI’s, many newer VW’s and other import cars have recommended oil change intervals of 10,000 miles with the proper synthetic oil.

Also…TDI is a designation for Turbo Direct Injection, not Turbo Diesel (although TDI’s are diesel)

4

The show is in reruns; no new shows are being made. Historically, 10k is on the long side for OCI. Today, EU makes feature longer change intetvals (with a larger sump capacity to match.) Whether the primary consideration for this change is engine improvements, oil improvements, or green mandates forced upon the industry is, IMO, an open question.

At any event, I would be leery about a 10k interval with current low-SAPS oils without analysis. I’d feel better with an “old-school” diesel oil in an extended application (one with plenty of Zn, P, and a high TBN.)

5

The only way I would go 10,000 miles between changes would be if I did nothing but highway driving at moderate speeds.

6

I would LOVE to see a study of the people who do 10k oil change intervals and longevity. Are they getting 300-500k miles like I’ve been able to get with a 5k oil change interval??

7

As a younger A.S.E. certified tech, I was one of those"every 3000…on the dot" type guys for my OCIs on my personal vehicles for many years.One of the first shops I was employed with(class 8 trucks) introduced me to oil analysis, and it was a practice that I incorporated when I started a small otr trucking company of my own.

Heavy trucks aside(300,000 to 500,000 OCIs w/synthetics and by-pass filtration), I decided to analyze the oil in some personal vehicles.Yes, I realize that one oil analysis is costs more than an oil change for the avg commuter car.This was done just for my peace-of-mind.

What I found was that cheap dino oil can go well past the 3000 mile mark, depending on the condition of the engine(%blow by,injectors,CTS,FPR,head gasket,…etc) and typical driving conditions(ambient temp and long vs. short trips).

Car #1 Nissan Sentra(ga16de motor).: I consistently went 7500 miles on whatever oriely had on sale at the time(chevron,mobil,pennz,valv), always 10w30. If my routine involved daily non-stop freeway driving of 20 miles or more, I could push that to 10,000 mile before I saw degradation of any sort in the oil(viscosityand total base#).I sold this car at 250,000 miles with perfect compression in each cyl. To be honest, I have a freind that still has a similar year sentra that is in the mid 300s…and his idea of maintenance is add oil when it gets noisy or the light flickers.

Car#2 2006 Sonata I-4 Currently at 105,000. I was changing oil at 10,000 with penz synth when i was driving it with good reports from the lab. I probably could have pushed it to 15,000, but it’s just easier to remember to change at 70, 80, and 90 thousand. I gave the car to my daughter to drive and have since changed to dino oil (mobil 5w30) and back to a 5000 mile OCI. She drives much less than I and the car barely gets to operating temp by the time she gets to school. I could get more from the oil, but I doubt it would make it to 10,000 and a 7,500 oci is harder to remember than every 5000.

My conclusion? JUst because your dad changed oil every 3000, doesn’t mean you have to do the same.Today’s oil is much higher quality and we don’t have carburetors anymore contaminating the oil with raw fuel(although a stuck injector will do the same thing). Jiffy lube (or Autozone)says you need to come back every 3000. Why? What’s their motivation?.. What other countries have built a billion dollar industry on changing oil? I don’t see it when I travel in S. America anyway, and I think Europe is similar.

Can I tell anyone when exactly to change the oil to maximize their consumer dollar and minimize their eco-impact? Nope. A lot of variables to consider.At the very least if one knows his/her gas mileage avg and can tell when they are running rich,you have a better chance of extending the OCI. I choose to use a quality synthetic, a good filter (purolater white or gold, napa, or rebranded champion, hastings, wix) and change it every 10,000 miles.

Anyone that wants more info, “bob is the oil guy.com” is a great forum full of info from oil nerds like me.

Polaris labs, Blackstone, Lab One (here in Phoenix) are a few examples of oil analysis labs. I won’t buy a piece of equipment without taking an oil sample first. It can tell you so much info. High lead/copper =bearings, iron=gears, potassium(if i remember correctly)= coolant(head gasket), %fuel dilution= bad injectors/temp sensors/rings…just to name a few things.

Anyway…sorry for the long-winded rant.

8

FYI, several high end cars now come with the ability to read oil quality in real time, and recommend OCI accordingly. I know Benz has this, others probably do as well. My buddy’s Mercedes (gas engine) has been averaging 12,000 miles between recommended oil changes. The oil is of course full synthetic.
For those of you doubting this wisdom I would ask: do you really think the engineers at Mercedes want to see a high engine failure rate on their products?

9

I was wondering about this as well (so much so that I created this account). I always used to change my oil (dino oil) in my gas-engine vehicles every 2500-3000 miles (or 6 months). When I bought a 2013 TDI (SportWagen), I was shocked to see the OCI listed as 10k, right from the start! I researched this extensively and found that indeed that is what folks were doing. And still they were getting 200k+ miles on their TDI’s.