This may be a dumb question but what kind of gas does my
1972 280sel 4.5 take.

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1972 280sel 4.5

It takes whichever grade keeps it from pinging. That's the rule for any car.

10 years back, only super had the best additives for cleanliness. Now, all of the major brands and most of the not-so-major ones have the same additive packages.

When my 81 suburban is towing a trailer (usually loaded with a benz), it insists on super. When there is no trailer attached, good old regular works fine.

-CTH

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- cth350@gmail.com
http://www.111lakeside.com/

Well I am going to presume your car does not have a catalytic converter since it's a pre-1975 model. The engine is probably designed to run on leaded fuel. I agree with using whatever the car likes the best. I once owned an old Subaru that originally called for 87 octane, but since the car had 173K miles on it when I bought it, it would ping like hell on 87. So I put super unleaded in it, and it liked it. Guessing what gas to use is tough when you're talking about an older car. Gas has improved since the engine was originally built, so it's a tough call.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

I rebuilt my rust!!!! free 450 SE last year and i've
been running reg. gas since and it runs great and start's
fine even in the hot weather.And with the price of gas
up here that's a plus.Those motors wear not horsepower or
compression beast!!!! P.A.RONDEAU 20 YEAR M&B TECH.
MERCEDES OF BLOOMFIELD HILLS

MBs since the '50s? were designed to run on unleaded fuel. As far as your 4.5 goes, I would really suggest you stick with premium. Higher octane can provide better economy and if you happen to be driving up any grades, it will not knock. My '67 250 calls for 96 RON fuel, which obviously is no longer available, but I run Sunoco Ultra 94 in all of my gasoline MBs. They all run quite well on it. A friend was telling me that he got 112 octane fuel when he had his 300SEL 6.3 at a racetrack out in Portland, Oregon and the tips of the tailpipes were white, which is the way they're supposed to look! Clean!

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Regards,
Aaron

Higher octane can provide better economy

After working in a fuel lab at FOMOCO for several years the economy and power gained by higher octane was so insignificant, it was actually measured in decimal points.

Ammoco and several other fuel companies were charged with consumer advertising fraud with claims of more fuel economy.
They, of couse won there suite, because though the amount of economy gained was a proven fact,they never claimed any amount they just implied more,
...even if it was .0056 more to the gallon .
If it Knocks and every thing like EGR and Engine Mechanicals are ok , back the timing off a few degrees.
It MUCH Cheaper than 20 cents more a gallon.
Regards,
Bryan