Oil consumption survey

[Markus]

What is your oil consumption? What is considered normal for these engines? :?:

[hill]

Check my oil every other fillup, Added none between chnges. But by the stick it consumes about 1/2 qurt for 3k mileage.

Happy Benzing
Darryl, Hill
350 SL4.5 #60
1967 250sl "California"

[Longtooth]

I've measured my oil consumption continuously since I bought the car in '84.. both before and since the engine was rebuilt.

Oil Consumption Spec's (from BBB) for the 230SL and 250SL are from 0.15 - 0.30 liters/100 km, or 0.16 - 0.32 qts / 62 miles.

Those spec's translate to 194 - 388 miles/qt. ...the higher rate of consumption (194 miles/qt) occurring at high speed freeway driving (according to the notation in the BBB).

For the last 5k miles before engine rebuild I averaged 292 miles/qt.... Cylinder #1 burning oil and fouling the plug badly.  That was still better than spec's, but I didn't like adding a qt of oil every fill-up.... so it was time to rebuild the engine (117k original miles).

After the engine rebuild, for the 1st 5k miles I averaged 1258 miles/qt, with the consumption as low as 750 miles/qt with a period of high speed long duration driving.  This was far, far better than spec's, so I assumed it was due to the tight engine.

However, for the last 5k miles, now with 14k miles on the rebuilt engine the oil consumption has averaged nearly 1000 miles/qt (991).... admittedly this is with high speed long duration and heavy on the throttle driving... while for the 1st 5k miles after the rebuild I drove more/less conservatively (by my standards).

I use 10W30 or 30W Pennzoil or Castrol.

I believe the much better rate of oil consumption experienced has far more to do with the changes in engine oil technology than to my engine's relatively new rebuild, since even with a bad oil compression ring on cylinder #1 and fouling the plug on it I was still getting better oil consumption than the spec's!

For reference to fuel milage (reflects how engine is used... therefore may also have a relationship to rate of oil consumption):


Spec's (BBB) are 14.6 - 23.4 mpg for average highway travel + 10% more for the automatic transmission.  

At constant speed (110 km/hr = 68.2 mph) spec's are 22.9 mpg for the 230SL & 20.9 mpg for the 250SL... no adder for the automatic tranny.  

I averaged 16.8 mpg before the engine rebuild, and 14.5 mpg for the 1st 4k miles after the rebuild.... even though I was driving "conservatively"... I assume this was due to the engine still being tight or that I needed a valve adjustment after the rebuild wear-in period or the combination of both.

For the last 5k miles since the engine was rebuilt I've also averaged 16.8 mpg as I did before the engine was rebuilt, so my guess is that mileage reflects how I drive my 250SL manual.... seeing as it's the same as it was before I had the engine rebuilt.

My best fuel mileage has been 19.4 mpg in liesurely cruising at 72 mph and my worst 13.1... the latter reflects a typical "First Sunday Drive" in the SantaCruz Mountains... hard on the throttle 98% of the time and in lower gears (2nd & 3rd much of the time).

Longtooth
67 250SL US #113-043-10-002163
The 6% Club - Best of the Best
'02 SL500 Sport

[Jonny B]

My engine was rebuilt before I bought the car. I average between 1000 and 1200 miles before I need to add a quart. I use Mobil 1 5W-30.

Jonny B
1967 250SL Auto

[J. Huber]

Well, I usually change my oil twice a year -- maybe that's overkill but I do it myself and sometimes I just need to get oily. In the last several years I am averaging about 2200-2500 or so miles a year. In the course of a year, I rarely have to add any oil -- definitely less than a quart (maybe 1/2) between oil changes. How's that for obfuscation? I should be running for President!

James
63 230SL

[ja17]

Hello,

I have serviced for the last 35 years, an original 1969 280SL that has 135,000 miles on its original engine. The engine has never been re-built or opened for repairs. The oil is changed every 3,000 miles or once a year (which ever comes first).  It uses less than a pint between changes.

Joe Alexander
Blacklick, Ohio

[Longtooth]

Wow, the range of oil consumption is on the order of 6k miles/qt down to 1k miles/qt or so.  Both 250SL reports are in the 1-2k miles/ qt, all the others in the 5k - 6k miles / qt.  That's a 6x - 3x difference between high and low consumption.  Since my consumption is on a rebuilt engine (Metric Motors, LA) long block rebuild, with 14k miles now on it and I'm averaging on the order of 1k miles/qt, what's the major difference?  Driving style? Oil weight? Oil brand?  

My driving is nearly always agressive ... accelerations to 5k & 5.5k rpm, high speed 80 mph - 85 mph freeway driving, or high shift rates and accelerations on secondary roads driving.  

Is the driving style for those that are getting on the order of 5k & 6k miles/qt of oil a more conservative style?  What is oil weight used?.  I was feeling pretty good about my 1k or so miles/qt since spec's by MB are far worse even at the best (0.15 l / 100 km = 1.5 l / 1000 km = 1.6 qts / 620 mi. =  388 mi / qt)...so what's the magic given some W113's up to 5k miles / qt or more?

Longtooth
67 250SL US #113-043-10-002163
The 6% Club - Best of the Best
'02 SL500 Sport

[bpossel]

One additional item to factor into oil consumption would be the injection pump (fuel).  If too much fuel is being injected (ip pump not adjusted properly), then would this not thin down the oil and cause more of it to burn off?
Comments?
Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[J. Huber]

Daring to put my little toe in science, I am not sure 3 250s, a 230, and a 280 are a reliable sample. Maybe we need a few more numbers to find an accurate range? ... ok where's my shoe [:0]

PS I use GTX 10/30. I drive fairly tame compared to Mr. Longtooth (rarely over 60 MPH, primarily "around the foothills" miles). All on a long block replacement with 100k KMs (60K Miles?)

James
63 230SL

[Markus]

Perhaps, since these engines spend most of their lives at higher rpms due to final drive gearing, more rpms translates to an increase number of times that the sleeve is exposed to burn-off, hence the higher consumption. If your IP is diluting the engine oil with fuel, we have problem in the IP.(to rich or fuel leaking past the plungers and barrels into the lower case of the IP)
Hopefully the folks who have converted to the 3.27 axle will chime in with their oil consumption data.

[hill]

quote:Originally posted by Longtooth

Wow, the range of oil consumption is on the order of 6k miles/qt down to 1k miles/qt or so.  Both 250SL reports are in the 1-2k miles/ qt, all the others in the 5k - 6k miles / qt.  That's a 6x - 3x difference between high and low consumption.  Since my consumption is on a rebuilt engine (Metric Motors, LA) long block rebuild, with 14k miles now on it and I'm averaging on the order of 1k miles/qt, what's the major difference?  Driving style? Oil weight? Oil brand?  

My driving is nearly always agressive ... accelerations to 5k & 5.5k rpm, high speed 80 mph - 85 mph freeway driving, or high shift rates and accelerations on secondary roads driving.  

Is the driving style for those that are getting on the order of 5k & 6k miles/qt of oil a more conservative style?  What is oil weight used?.  I was feeling pretty good about my 1k or so miles/qt since spec's by MB are far worse even at the best (0.15 l / 100 km = 1.5 l / 1000 km = 1.6 qts / 620 mi. =  388 mi / qt)...so what's the magic given some W113's up to 5k miles / qt or more?

Longtooth
67 250SL US #113-043-10-002163
The 6% Club - Best of the Best
'02 SL500 Sport

In my case the low use of oil is probably due to me using it as a daily driver. It rarely sees 4k rpm with the daily comute. Unless the kickdown selonoid is in play it shifts between 3200 and 3600. Even at 80 mph its at 3900. Oil is 10/40 Q +. If you drive agressively some oil usage is a good thing.    Tight rings and with little oil seepage is not the way to build a engine that will be used hard.

Happy Benzing
Darryl, Hill
350 SL4.5 #60
1967 250sl "California"

[Raymond]

I have 6,000 miles on my rebuild of my 280. During that time I've had my share of fiddling with the FI pump and mixture from too rich to too lean and back to about right I think.  My driving is "spirited",  I use Mobil 15w-50 pure synthetic, and burned less than a quart before each oil change at 3,000.

Ray
'68 280SL 4-spd Coupe