Too Much Oil!!!!
 

Sad tale.


Well, folks, I have a real nice 450 SEL '77 (German spec pwoer) with 64K on clock. got it last September from original owner. always garaged, serviced, but not used much over last several years.
anyway.........

I live in South Florida. Engine ran smooth and like a bear, with enormous gobs of pwoer, until about mid-to late May. Since then, it has started what I can only describe as 'fluttering' if I give it more than just a slight amount of gas on acceleration. No backfiring; just a fluttering absence of pwoer, until I ease off a bit on accelerator. Has been getting worse since late May.
Car looks great under hood, except for some dirt and grime, although I suspect plugs have not been changed in a long time.

Anyway, like a fool, I had Jiffy Lube do the oil change on May 14th. (I've only driven 1500 miles since then). Just today, I recalled that during the oil change, the guy said he was putting in extra oil maybe a quart or two more. I can't remember the reason he gave. They used 10W-30 at my request.

Based on story related above, the timing and the evidence so to speak, do you think that my 'fluttering' on moderate acceleration could be related to too much oil, compunded by using 10-30 in a beastly climate with short hop driving? I will pull a plug to look tomorrow some time, but I thought I'd get some opinions.

thanks!!!

best bet would be to check the oil level using the dip stick. If the sticks shows that the oil is way over the recommended max, then i'd have it drained and then simply fill it up with the correct amount. I don't know what that jiffy lube guy told you, but 1 quart seems like a lot of oil (We use the metric system here).

ALso, i'd use a thinker oil. Somthing like a 10W50, 15W50 :)

Just a note, I once knew someone that changed his own oil, he though you had to fill the engine all the way to the top. 32 Liters of oil later....

Jiffy lube normally allows for 5 or 6 quarts of oil. Mercedes usually take 8 quarts of oil in their cars, at least everone I have owned does. So the extra quart should have been 2 extra quarts under normal conditions. Pull out the dip stick and see what you have!! Below the minimum is not good, if so then add some, This will not ruin anythign is 1500 miles. Over filled is not good. the reason the manufactures have a maximum is so that the crankshaft does not enter the oil while rotating and cause it to foam which prevents the oil form lubricating the engine correctly. I don't think that 1 quart over the max would cause a problem.
Again check the oil level.
The fluttering sounds more like a air fuel mixture problem OR as you said a spark plug problem.
Check them and let us know how they look. Color, build up, etc. Spark plugs tell alot about the burn in a cylinder.

Dave

The solution to this problem is simple:

- Find out the oil capacity of your car.
- Change it yourself.

Quick-Lube places are notorious for overfilling. If you can find a place that still pours it in a qt. at a time, that might work. These automated filling systems are dangerous in the hands of people who don't know what they're doing.

OIL FOR 300SEL
 

I have an 89 300 se and I believe the se and sel had the same straight 6 motor. My se takes 6.3 quarts. I also have a 90 420 sel with the v8 and it takes 8 quarts. Hope this helps.

to dmorrison and others
 

Fellows:

Changed oil immediately to 20W-50 Castrol, considering the 90-degree heat and 100% humidity here (S. F;lorida).

In adition, pullked just a couple of plugs today and can report cpondition:

Bosch W8DC's. No residue anywhere. Tips and gaps still good. Tips and electrodes are kind of bleach white in color - from heat, I suppose. But no wear evident or reside.

what do you think now? Still an air/mix issue, i.e., the 'fluttering' on moderate-heavier acceleration?

The fluttering problem may be a vacuum leak. Check all the vacuum hoses and replace those that are hard and deteriorated Also check the timing and vacuum advance, if your car has these design features.

Check your tranny fluid, too, and do a tranny service if one hasn't been done recently.

I blew a tranny cooler line on Sat, fortunately as I was picking elderberries so I was close to home and not on the highway. After replacing the lines and doing the tranny service, I filled it back up with Mobil 1 synthetic ATF (all seven quarts!), and my shudder on acceleration was gone.

I suspect I had a leak for a while -- oil puddles at work where I park, etc, so I think the tranny was low on fluid and the torque converter wasn't full, causing the shudder.

I drove it into the garage, and it acted almost normal, but nothing came out of the pan when I pull the dipstic tube off, and there wasn't but a cup or so of fluid in it when I dropped the pan. Torque converter was nearly empty, and I was getting air out of the cooler line......

Peter

No, Peter.

My transmission fluid is fine. It's not a shudder. I know those from past Benzes.

It's more a sense of fluttering.....a loss of power. More liukely a vacuum and/or fuel/air mix thing. Or both, since I've messed with those items. Bad boy!!!

No fluid leaks.

But if you will recall, that strut that runs connected to rear of a throttle roller linkage down towards tranny. I've not dealt with that. It's connected, but moves around too easily.

Might still be that?

No, it's supposed to be like that, it's connected to a ball link on both ends. Flops all over the place.

I'd suspect an ignition problem rather than a fuel problem -- unless you are WAY rich, with black smoke blowing out the back!

Dont' forget the fuel pump/fuel pump relay and fuel filter -- low delivery will cause cut-out on acceleration, too.

Peter

Peter:

When you say ignition problem, might it be the battery?

Funny thing. no matter how often I clean the negative post on battery, which is a relatively recent MB battery, it gets ugly and cruddy white/green within a day!! Any thoughts?

Since plugs look fine, and wires as well, I'm more apt to dismiss ignition thing.

Sounds like the alternator is overcharging, and the battery is gassing. I would suspect the voltage regulator.

re: Battery:

So if the battery is overharging, and voltage regulator is involved, would this affect engine/acceleration performance?
how?

And where, on M117 engine, is voltage regulator located?

thanks!!

Spray some white lithum grease on the negative cable, it's got acid on it.

Voltage regulator is intergral to the alternator, held in by two screws. Make SURE you have both battery cables in good condition and properly connected, and that the body ground is good, or the ignition may be cutting out with engine movement.

Check the voltage across the battery at idle and at 1500 rpm or so -- if it goes over 15 volts, the regulator is shot. These usually fail open, though.

Peter

Peter:

Is interesting what you say about batery cables. The connection form negative cable to front frame memebr (only about 8-12 inches in length) is slightly corroded at the body point. We just had a downpour of 45 minutes. when I went outside now to start car, it ran rougher again. Funy. When I turn it off and restart, it goes smoothly for a minute or so before picking up roughness again.

Also:

when I got car, I changed cat on left side. Something broke off inside cat recently (maybe a piece of the exhaust pipe inside flange), and is making a marblew sound inside cat at various rpms. I also think ?I might detect something burning slightly within cat, but it's not the rotten egg odor.

Do you think my hesitation and cutting out might in some way ber elated to the cable?