Oil for a '74 Mercedes 450 SL

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This old iron engine is noted for very long life and for not being really picky about oil used.
Certainly one of the best engines ever installed in any Mercedes, including the sainted diesels.
What specs does this inexpensive Techno oil claim?
If it meets decent specs, use it and enjoy the savings.
In general, a 5W-40 is a better choice than a 10w-40, since it's usually a better oil.
OTOH, if this engine has run happily for decades and many miles on 10W-40, why try to fix what isn't broken?
 
Techno 10W/40
API SL/CF
Daimler Benz 229.1
VW 500.00/505.00
ACEA:A3/B3

Techno 5W40
API SM/CF
MB229.1 and 229.3
BMW LL-98
VW 502.00 / 505.00
GM LL-B-025
Porsche


Just worrying about the zddp levels. got the cams redone, they where a litte to sharp.

can't remember if it is flat tappet?
 
This engine would not have a rollerized valveltrain, but since it is OHC and is not a high-performance unit, valve spring pressures should be pretty moderate.
If you trust the reported specs from Techno, either of the grades you've listed would be fine.
This engine was born way before even API SL existed.
The 10W-40 would be fine and was probably among the grades Mercedes originally recommended for all climate use.
 
Rotella in a 40 weight is what I used to run in my old mercedes... These engines love a HD oil. In a warm climate I would go with a 50 weight oil...
 
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So there's no need of any higher ZDDP oil for the 450?

Want the best for this princess, would be a shame to have invested this amountmoney for a complete overhaul but not giving the heart of the car the blood that she needs..
 
This engine had no special oil requirements when it was new, other than fairly thick grades, so I doubt that it does now.
I don't think you'd go wrong using a name brand HDEO in a forty grade, whether a 5W-40 or a 15W-40 and I think that M1 0W-40 would probably be a solid choice if you're willing to spend the money to use it in a car that won't see very many miles.
I do think that this engine would be perfectly fine on the Techno 10W-40, but it is your engine, your money and your choice.
If it were mine, I'd probably run the Techno.
It's not as though this thing is an all weather daily driver on which you'll be racking up the miles.
If you're concerned, do a couple of UOAs just to see how much metal is getting shed and how well the oil holds up.
If it looks bad compared to other 4.5s, then you might consider a different oil.
 
Thanks for your advice. Definately not going for m1 or something like that. With almost 10 litres of oil needed, the oil change will cost over 200$!!!

I will try and go for the techno 10w40, they also have 15w40. The 15w40 is even cheaper, but fully mineral. I'd rather stick with semi-synthetic.
 
Yes, the ones they're talking about would have an ACEA E spec. What I'm running in my G is an E7/E9, but in North America, we worry more about the CJ-4.
wink.gif
 
Just searched some informating about the ACEA E oils.

For what i understand, The E4 and E7 rating would be the most suitable for the use in the 450 because these are not low SAPS and the E6 and E9 are rated as Low SAPS.

Also what i understand is that the ACEA E oils are meant for engines that don't rev higher than 2500 RPM.

It's not that the engine is exceeding this RPM's much, but at highway speeds ( 75 MPH ) the revs are about 3500.

Also I sometimes hit the kickdown, so it will see 5k+ RPM occasionally.

Don't know if it matters for the oil choice, but I'd like to say again, the car is running on LPG ( Liquified petrol gas ).
 
I wouldn't worry much about the revs when using any reasonable E rated oil at operating temperatures. It's not going to be an issue. HDEOs are used routinely in engines that exceed 2500 RPMs.

With respect to running LPG, there will be nothing wrong with running a lower SAPS oil (within reason) or one with lower TBN. Fuel dilution won't be an issue in your case, and rather long OCIs would be possible.
 
Bought the Techno 10W40 a week ago. Will change the oil within a week or so.

Added Wynns supercharge a few months ago, noticed that after a 100 mile drive, there wasn't any blue smoke visible after lifting the gas @ higher rpm's. Oil usage has drastically decreased and the crankshaft seal isn't leaking as much as it did before.

I'll pour another container in during oilchange.
 
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