Fuel mileage for 560SL? - PeachParts Mercedes-Benz Forum

Omaha 560SL · #1 05-02-2011, 11:25 PM

I just bought my first Mercedes (1988 560SL), but would like to know what kind of fuel mileage I should expect. My first 120 miles of mostly highway driving provided only 13 mpg. I just replaced the air filter, which still showed light through, but the car had been stored all winter with an empty tank. I filled it when I bought the car and added fuel conditioner, but should I expect the mileage to get better as I run it for a while?

oldsinner111 · #2 05-03-2011, 06:37 AM

If the spark plugs are good run it hard for 50 miles or more.Then fillup and check mileage, driving it normally.

rocky raccoon · #3 05-03-2011, 07:40 AM

Your mileage is on the low side. I too have an 88 560SL and get about 17 mpg in moderate speed country road and town driving. All-town expect about 15 mpg. I have seen near 20 mpg on a steady speed 200 mile highway trip.

My car is driven daily and I maintain it well. Fresh plugs, fresh PREMIUM-grade fuel and elimination of vacuum leaks if any will make a big difference. They are great cars. Any minor penalty in fuel mileage is amply repaid in the joy of driving.

Omaha 560SL · #4 05-03-2011, 01:24 PM

Thank you for your input - I will check the plugs and check the mileage again once I have gone through one tank of gas. I did fill up with premium and would be happy with 17-18 all around and 15 in town. The previous owner drove it here (Omaha) from California and said they got 26 mpg at 65 mph when they moved here 3 years ago, so it may just be needing a good run to clean out the fuel system. Thanks!

rowdie · #5 05-03-2011, 08:20 PM

The PO lied. Unless they were talking about a 65mph tail wind all the way from California.

ericdee · #6 05-03-2011, 08:42 PM

Quote:

Originally Posted by Omaha 560SL

Thank you for your input - I will check the plugs and check the mileage again once I have gone through one tank of gas. I did fill up with premium and would be happy with 17-18 all around and 15 in town. The previous owner drove it here (Omaha) from California and said they got 26 mpg at 65 mph when they moved here 3 years ago, so it may just be needing a good run to clean out the fuel system. Thanks!

Hate to pop your bubble, but 26mpg is pretty unlikely... maybe down hill

.

I've seen these cars get 13 to 20 mpg.

abiby · #7 05-03-2011, 09:53 PM

Quote:

Originally Posted by rowdie

The PO lied. Unless they were talking about a 65mph tail wind all the way from California.

My theory is they filled up in Denver and checked the mileage from there to Omaha... all down hill.

vista598 · #8 05-16-2011, 08:50 AM

The offical US Gov. report says 12 mpg city and 16 mpg highway. Source: http://www.fueleconomy.gov/feg/noframes/1713.shtml
My 560sl get just about what they report. Not exactly a "green car".

KCM · #9 05-17-2011, 06:02 PM

Hello fellow Nebraskan. Welcome to the SL club.

That 26 MPG SL fits in the same world with the 35-40 MPG 300 diesels (the world of fantasy). I get right around 17 MPG whether I drive at 55 or 75 on the highway. City driving does not seem to reduce it much at all. I have done a lot of work on mine though, including a valve job, new injectors, plugs, and wires. There isn't much on the fuel and ignition systems that I have not touched, so that might have helped.

rowdie · #10 05-17-2011, 09:27 PM

The window sticker on my '86 has 17/14. I get 19 highway. Don't know about city.

Omaha 560SL · #11 07-16-2011, 12:45 PM

Thanks for all the input from those that responded to my first question. I replaced the spark plugs (easier than expected), replaced the air filter and ran it for a while before filling up and checking the mileage again. I took it for a long drive over some 2-lane highways of eastern Nebraska and got 18.5 mpg, which I will be very happy with.

jplinville · #12 07-17-2011, 06:20 PM

That 18.5 isn't your average. I've had mine calculate up to 19.5 and down to 14 on the highway. Calculate them each fill up and average them out after having 5 or more fillups.

As for ways to increase the mileage...make sure the resistor is in the ignition to retard your timing, use very low to no ethanol fuel, make sure your fuel is of good quality, run Techron occasionally, and keep your foot off of the firewall.

rowdie · #13 07-17-2011, 07:56 PM

Quote:

Originally Posted by jplinville

That 18.5 isn't your average. I've had mine calculate up to 19.5 and down to 14 on the highway. Calculate them each fill up and average them out after having 5 or more fillups.

As for ways to increase the mileage...make sure the resistor is in the ignition to retard your timing, use very low to no ethanol fuel, make sure your fuel is of good quality, run Techron occasionally, and keep your foot off of the firewall.

This from the guy who did over 100mph across Nebraska.