Oil change frequency on W126 1991 500SE?

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Roygarth

Active Member
Joined
Aug 12, 2009
Messages
99
Location
Norfolk
Car
1983 W123 230E
How often should I (local garage!) change oil & filter?

Which oil should I use?

Thanks
Piers
 
I use 10W/40 and aim to change the oil & filter every 6 to 8k miles. As you'll discover, the oil filters are the cannister type & you might as well buy them from Mercedes as they're only about a fiver each.

All you need to complete the job is a container for the oil & a 10mm socket to fit both the sump plug & to take the bolt off the oil cannister which is conveniently accessed from above.

There's so much clearance under a W126 you don't even need to raise the front. Plenty of room to reach under to take the sump plug out & place a suitable dirty oil catcher. Remember to put the new copper crush washer around the sump plug when reinstalling & also remember to put the new rubber seal around the oil cannister lid having smeared a bit of clean oil on it first (both these items come with the Merc approved filter).
 
Imo, Fuchs oil is good, and Magnatech/GTX all up to par at 10w40.

As to frequency, 6k sounds on the fastidious side. 8k sounds about right. If I may direct you to this thread on w124 oil/filter change frequency the same will apply with your w126.

Then again, oil is (relatively) cheap, an engine overhaul isn't.

Is this the 500SE you bought recently? If it is, and imo looks stunning btw, I'd go for 6k mile changes.
 
I do it at 5k or annually, whichever comes first.

If you do it yourself, note that the tightening torque for the filter is 20 Nm (perhaps 25) -- hand tight, and less than a quarter of the torque for wheelnuts -- and for the sump plug it's a mere 25 Nm and not the gorilla torque commonly applied by Spanner Controllers in quick-change shops and guaranteed to round off the head.
 
At the risk of going OT, is an annual change absolutely necessary? Atm, I'm only doing around 2k per year in in the SL, I know that acidification is an issue with oil, but I change at the 6k mile mark; mine gets changed every 3 years. Am I chancing it?
 
I do all my cars annually... for me that usually means no more than 1500 miles.

Its cheap to do and gives peace of mind.

always use MB filters and decent 10w40 semi synthetic oil
 
I would certainly change oil and filter annually.
Condensation and acidic build-up in the oil all lead to engine wear and degradation.
Low mileage use can sometimes be worse for condensation build-up than regular high-mileage usage, which tends to reduce the condensation content by boiling it off.

Cheers.
Johnsco
 
Im doing the 500E today and using valvoline 10w40. I got it at £15 per 5l which isnt bad..
 
The original maintenance booklet states services to be done every 10,000 km which equals every 6214 miles. The rounding up for the Imperial conversion is casual & so increases by 6000 miles for every service.

I've owned a w126 of some sort since 1995 & my current 500SE has done 175k miles with the majority of oil changes using Shell Helix Plus and more recently using Castrol GTX 10/40. All of my servicing has only ever been done annually.

I did for about 5 consecutive services on a SEC use Mobil 1 0W/40 but there was no difference that I could detect. However when I used Bosch Super 4 spark plugs in the same SEC they were sensational.
 
I understand some oil grades in the US are different than in Europe (couldn't find the same in Europe, so its my assumption). On my 560SEL, I use mobil-1's 15W50 synthetic which I could go 8k miles on per year. However, I could never do more than 3500 miles in a year as I only drive the car in the summer. I end up simply doing an oil change once a year just like Jaymanek, where time plays a larger role than the distance covered.
 
Im doing the 500E today and using valvoline 10w40. I got it at £15 per 5l which isnt bad..

Could you give any indication of a change when using this oil?

I am currently using Mobil 1 with nice results but it gets quite expensive as I do mine every 5000 miles.

Dave!
 
Mainly oil pressure.

I went from Halfords semi synthetic to Mobil 1 and gained about a 1/4 of a bar oil pressure when hot.

It now sits at roughly 1 3/4 bar on a hot idle, dropping down to just under 1 1/2 after a hard run and dropping to idle.

Dave!
 
mine has always rested at around 1.5 bar at idle when hot..

The oil change hasnt affected this, but like i say, i hardly allow my oil to turn colour before its changed.
 
8 litres max., I think. Put 7 in and check the dipstick after allowing the oil to settle. Don't overfill.
 
As previously stated...
Every 6000 miles or once a year.
A reasonable quality semi synthetic 10/40.
Even if you are paying over the top it will cost less than £50 for bits.
Contrary to some thinking, the camshafts can wear on these engines, but only at huge mileage or if corners are cut on the lubrication side of things.
 

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