araltd

So we recently bought 2000 e430 with about 149k miles. My understanding is this vehicle was supposed to use only synthetic oil...? From the service records and receipts I have that came with the car- the previous owner apparently only used regular oil.

So now, with 150k miles on it, should I switch from regular oil to synthetic? or stick with standard oil?

Regular oil goes about 3000 miles between changes... how about synthetic? I've heard 10k miles between changes? Can that be accurate?

ADVICE APPRECIATED.

austinholloman

True synth oil will help with the life of the engine. It will also help clean out the build up that is currenty in the engine. It also helps prevent any leaks because its thicker. I would never let my car go 10k with out a change no matter who says so... Even with full synth in my M3 I change it every 4k to be safe. Remember the oil is the blood of the engine. Keeping it good and clean is never a bad thing and you cant be too careful.

stickygreen

Changes every 7500-10k miles should be fine with a quality synthetic, but I would change the first run of synthetic after 3k, just to drain any sludge/varnish buildup.

If you want to run the proper-spec MB oil, the most readily available are German Castrol (aka Syntec 0w30 european formula) or Mobil 1 0w40.

Other OTC oils that will work great (though aren't officially approved by MB) are:

Mobil 1 5w40 "turbo diesel truck"
Mobil 1 10w30 "high mileage"
Mobil 1 10w40 "high mileage"
Shell Rotella full-synthetic 5w40

saintz

I would only run Mobil 1 0w40. It is formulated differently from almost any other oil commonly available on the market (there are some similar oils, but they cost more). Just because you change the dino oil more often doesn't mean it's ok to use. Mobil 1 0w40 has specific additive packages, in addition to its long life, that make it recommended.

araltd

O'reilly's has a synthetic oil change package for $17.99 w/5 qts fluid. Otherwise its closer to $45 from autozone, etc... For the dealer to do it its $120 and other places its around $90'ish... Compare that with a standard oil change of around $40-$50 for quality oil.

At that cost - that would negate any fuel mileage benefit - because it's more than double the cost. So unless a person could get 7500+ miles between oil changes, synthetic oil is very expensive........

As for leaks, I had heard synthetic is actually THINNER than regular oil, with smaller molecules and can leak even if engine is not currently leaking with conventional oil. The smaller molecule's is what makes synthetic better - which makes sense to me. Get's in places regular oil doesn't.... And as such will get through seals, etc regular oil doesn't too.

Ideally I'd like to switch it to synthetic, but I don't want to break what isn't broken... ya know.

desired_speeds

I wouldn't put O'reillys oil into a beater, let alone a merc. A quality synthetic oil with a Mann fleece filter will be more than sufficient for extended drain intervals. I would still recommend 7500 miles in between changes as 10k still seems a tad high to me for off the shelf synthetics.

Onto the part about leaks. It is actually a myth that synthetic oil is more likely to leak when compared to conventional oil. Synthetic oils include more additives that prevent leaks, as it lubricates and makes the seals last longer. Synthetic oils are also better at fighting sludge and other buildups inside the engine. Conventional oil cannot stack up to synthetic oils in any way, besides price.

As for personal recommendations, I would recommend running Amsoil. I am in no way affiliated with Amsoil, so please don't take this as advertisement. It is simply a recommendation, as I am a very satisfied customer. You guys should check out Amsoil. They guarantee 15k miles or 1 year replacement intervals with the use of their filters for hard driving and up the 25k miles or 1 year replacement for normal driving conditions with use of their filter. I'm not sure if they make Amsoil filters for Mercs, but if not, they will sell the next best thing, which on their site seems to be Mann. Independent tests have proven that all of their fluids, are higher rated than any other comparable fluids on the market. The tests are all from an independent source, so it does not favor any brands and does not introduce extra bias. The only inconvenience about Amsoil is that it may be harder to obtain. I'm lucky enough to have an Amsoil dealer half an hour from my house. They carry all fluids, filters, etc. there and provide me with recent independent studies that reassure me that Amsoil is truly the best each time. This is where I got the information that synthetic is less likely to burn or leak compared to conventional. Fluids from Amsoil are comparable in pricing, and may be even cheaper than other synthetics. I buy mine by the case and it ends up being around $5.50/ qt. The local Kragen/O'reillys stocks royal purple for $9.99/ qt and Mobil 1 for around $8/ qt. making Amsoil a bargain. Ordering Amsoil online may end up be more expensive than $5.50/qt., but then again they ship to your door.

Sathinas

Do you have any Used Oil analyses to make that Amsoil claim, or do you just go by what Amsoil says?

I'm not trying to stir the pot, but I've heard the "amsoil is the best" line one too many times without any UOA's to back it up, from such people.

desired_speeds

Good point. I think I will try out the oil analysis at 7500 miles on this oil change.