cdnbacon

I bought an '06 CDI in June '10 and have changed the air and fuel filter myself at the 26k miles service point. I don't have the suction tool so I bought the oil and filter on line and took it to a local MB garage today. They used the lift method and I'm thankful they did. Taking off the under covers revealed the beginning of a transmission oil leak emanating from the "electrical plug" (sorry don't know the correct term). Apparently it's a common problem, but replacing the plug fixed it before making a mess of the car or possibly worse for the transmission. The car doesn't have that many miles on it so I suspect it's an age related thing.
For those DIY'rs who suck the oil out, be aware that you will need to inspect the underside of the car at intervals to check for leaks.
I noted that the owners service manual recommends services at 13k mile intervals; checking with the garage they recommend changing the oil and filter every 6.5k miles. I would recommend this routine regardless of how hard the car is driven.
I've enjoyed all of your advice wrt the fuel filter changes - it gave me the confidence to do it and it was fairly easy.

kkanuck

Changing the oil at 6500 miles is incorrect information. It is harder on the engine believe it or not. In Europe they go even longer than the 13,000 mile we here in the USA are told to do. A Garage telling you to do more frequent changes is looking out for there wallet, not your best interest.

The Transmission leak at the wire connector is a common issue, and you should be able to have that covered under warranty.

220S

It's not incorrect information, it's simply subjective information.

This has been discussed to death on this forum and every forum in the universe.

kkanuck

I stand corrected....

You are correct. It is subjective.

I am speaking of the Diesel in particular, and based on using factory spec oil, namely Mobil 1 0W-40

However if you let the oil testing labs (Blackstone etc.) do the talking, (if you were to send your oil in for analysis at 6500 miles) and let the facts speak for themselves.

220S

Yeah, I've been doing OAs for a while both on my Porsche and my AMG. With the AMG I've been now going with longer OCIs based on those OAs. It looks like I can extend the OCI based on my own personal environmental and driving conditions. But with the P-car my OCIs are still at 6-7k which includes occasional track time and which means more oil (and brake fluid!) changes.

nopcbs

How, exactly, is replacing used/contaminated oil with a fresh charge of oil harder on the engine?

This is going to be good!

- nopcbs

kkanuck

With modern Mercedes Diesels, the blacker the motor oil gets, the better it's working, modern oils keeps particles of oil suspended. The oil filters help a lot too.

With proper oils used, Mercedes has an extended change interval on diesels of up to 40K kms, but you will not here that stateside.

Google and you will find useful information regarding this.

Here is a link talking of 25 year oil change intervals! http://www.maximumoilchangeintervals...intervals.html

220S

Believe it or not, theoretically it is true. But it doesn't mean that fresh oil is necessarily going to be harder on the motor than old oil. All it simply means is that changing too often can be more damaging in the long run. That "too often" part is what is subjective and really should be determined by your own OAs since everyone's specific motor, driving characteristics, and environmental conditions will differ.

Here's from Charles Navarro of LN Engineering (who builds NSC cylinders for Porsche motors and is a lubrication specialist):

"Against conventional wisdom, engine wear decreases as oil ages to a certain extent, which means that changing your oil more frequently actually causes engine wear; these findings were substantiated by studies conducted by the auto manufacturers and petroleum companies, leading to standard drain intervals increased from 3,000mi/3 months to 5,000-7,500mi/6 months."

It's also why today we don't change oil every 3k like we used to in the past.

nopcbs

OK, what we have here is somebody saying something that is very counter-intuitive and offers zero rationale behind the claim. What is this theory you refer to? And just where were these studies reported? I can see how over time you will loose some of the lights in an oil and this might improve lubrication properties for a hot engine, but you are also going to add abrasives that the filter does not catch, increase sludge which hinders cold engine lubrication and chemically degrade/wear out your additive packages. None of that sounds real good to me.

- nopcbs

220S

Read carefully: "But it doesn't mean that fresh oil is necessarily going to be harder on the motor than old oil. All it simply means is that changing too often can be more damaging in the long run. That "too often" part is what is subjective and really should be determined by your own OAs since everyone's specific motor, driving characteristics, and environmental conditions will differ."

It isn't just "somebody" saying this, it's the petroleum companies and the auto manufacturers: "which means that changing your oil more frequently actually causes engine wear; these findings were substantiated by studies conducted by the auto manufacturers and petroleum companies."

As an example, take a look at Conoco-Phillips report and the SAE Tech paper 2033-01-3119: "Engine wear can decrease as oil ages. This has been discovered in testing conducted by Ford Motor Co. and ConocoPhillips."

This isn't something new at all. Look at the oil company websites. And the API and SAE reports, etc..

And then there's always BITOG
http://www.bobistheoilguy.com/cms/

Check BITOG, and read what the manufacturer's have posted on the forum there (engineers from Mobil 1, Pennzoil, Castrol, have posted many threads there.) Interesting reading.

Again, and I stress this, just establish your own OCIs through your OAs. That's what will give you the 'correct' OCI for you and your specific motor.

And no, if you want to change your oil every 3k you won't kill your motor. Just like you won't kill it changing every 7.5k. Or 10k (if the OAs look good.) But you will be wasting money and oil. Unless maybe you're a mailman driving stop and go while delivering mail everyday in the Sahara Desert