A few oil change questions... (C280)

[David C Klasse]

I changed the oil today on my 1995 C280. I purchased 6 quarts of Mobil 1 synthetic 15w50 and 2 quarts of Mobil 1 dyno 10w40; and a Fram oil filter.

1. What oil filter do you think is best? What should I stay away from?

2. After sucking all of the old oil out, I will run the engine for about 30 seconds at idle speed. I read in a book called DRIVE IT FOREVER that this will help get any remaining oil out of the engine. I have done it for every oil change since. I can suck a little more out after doing this... will this harm the engine? Considering there is still *some* oil between the cylinders, and it's only for 30 seconds... do you think getting the extra dirty oil out is worth the minimal wear (if any) on the engine?

3. I put in 5 quarts of oil, ran the engine, checked the oil and the oil level had barely nudged the dipstick... my question: the oil light did not come on, at what level should it? (Light is operating though.)

4. The 2.8 M104 engine can hold 7.4 quarts of oil. Today when I was changing my oil, I put in 7 1/2 quarts, ran the engine for about 1 minute, checked the oil level, and it was below the 1/2 mark on the dipstick, wouldn't it be at the full mark?

5. Before changing my oil, I let the oil cool down for about 15 minutes as to not collapse the topsider tube too much. Well after about a minute of sucking, the 5/8 hose gets suck closed, oil still passes through, but not much. Is this supposed to happen? I looked at the hardware store for a different type of more heat resistant 'piping' but they didn't have any.

6. I have been gradually mixing synthetic into my oil. The first oil change I put in 3 quarts synthetic and 5 quarts dyno, this time I put in 6 quarts synthetic and 2 quarts dyno, next time I will put in 8 quarts of synthetic. Is this an ok way to do it (gradually)? I did this so there would (maybe, if at all) be a warning to a *possible* oil leak. Everything is fine so far, and I have 95k miles on car.

7. This questions pertains to trans fluid. I had my trans fluid changed about 6k miles ago at a MB dealership in Tucson. I changed it because when driving at speeds of 100+, trans would spill out onto manifold and smoke, thus too much trans fluid (and it was time for a change). Fluid still looked when changed though. After my oil change today, I checked the trans fluid... and it was overfilled? Or so I think... I have a picture below to help depict... you can't really tell the fluid level, but it was about an inch above the highest arrow for operating temperature level... should I suck some out?



When checking the fluid, I insert the dipstick all of the way back into the slot (like lockin in place), and then pull out. Also, should the dipstick be curved? It's always a real ***** inserting it back down the hole.

8. Throughout the course of my last oil change (duration 3600 miles), I burned a little oil. When I changed the oil, I put in a full 8 quarts (I know now this was too much). Well when I checked the oil level again prior to my oil change today, I noticed that the oil level was 1/2 way down the dipstick (between Max & Min). This means that I burned more than a quart of oil during that time. I do a fair amount of freeway driving (constant runs of 3,000 - 4,000 rpms when driving this fast), so a little loss would be understandable. Could this also be in part to the fact that I mixed in some synthetic? I ask this because: "If [synthetic oil] directly into an engine [(priorly using dino oil)] without flushing you will suffer oil consumption due to debris which is cleaned out by the detergent additive package of the synthetic oil." Also, I was thinking this could be from the lower weight used (10w30), for the 5 quarts of regualar dino oil I used (synthetic was 10w40).


I hope this all makes sense and I didn't overwhelm anyone.
THanks for all of the help everyone!!!

[Edited by David C Klasse on 07-27-2001 at 11:47 PM]

[David C Klasse]

Ok, well I realized that the oil level was nicht high enough because the oil wasn't warmed fully. Checked it again after a good run and it was perfectly at the FULL mark.

Also, I forgot to check the trans fluid level with the car on. It's PERFECT, I tested again with car on at warm temperature.

Sorry, I should have realized this!! Oh, and trans dipstick is not curved... there is one small kink towards the top but I think that's for the curve in the tube.

Thanks again everyone.

[David C Klasse]

But even running the engine for 30 seconds with some warm oil already in their to protect moving parts seems lesh harsh than starting a cold engine with thick (cold) oil and running it for 30 seconds getting the oil in there...

[MikeTangas]

David,

If it was my car I damn sure wouldn't run it without oil. I don't even like to start my engine up after an oil change, because it runs dry for a few seconds - but that is a necessary evil.

PS: Dump the Fram as soon as you can, stick with the OE filters.

[David C Klasse]

What brand is that, simply MERCEDES-BENZ?

Ok... on to the other questions.

[stephenson]

Gosh, David ...

1. Don't run any engine without oil.

2. The extremely small amount of oil remaining in an engine after draining or pumping is irrelevant - figure the quantities ... and marginal differences.

3. "Easing" an engine into using synthetic? It's an engine, not a date!

George

[David C Klasse]

Stephenson,
There has been an idea that if you switch to synthetic, you could spring oil leaks, read above what I said before.

[DEPRIEST]

As far as running an engine with no oil in it, I simply wouldn't do it. One trick that I always do is unhook the coil lead so the car won't fire. Then I turn the starter motor 2 or 3 times for like .001 second. This just barely moves the parts around inside the engine. I also make sure the oil fill cap is off. This ventilates the engine. Then I give the car about a half an hour for the remaining oil to drain to the bottom of the pan. I don't use a top sider. I went the the Larry Bible School of oil changes. In fact, tonight I'm going to "Change it hot... Change it often." When I get home from work, I'll go inside, put on my cover-all's and go back out and drain the oil using the standard old oil drain plug just like my father did, and his father before him. Tomorrow I'll finish the job. As far as synthetic goes, I used to swear by it. Now, I don't bother. It's a finer grade of oil and it leaks out easier. Standard oil works fine as long as you stay on top of the maintance. Also, Fram filters are to your car what burger king is to your body. Next time you're at the dealership, grab a half dozen of the good ones and keep them around. Infact, I bet mercedesshop has a better deal on them.
Good Luck

[longston]

You are a victim of information overload. All of the opinions here have caused you to accept most of them as valid, and try to seek a compromise. This results in confusion.

First, NEVER run your engine even for 30 seconds without oil.

Second, Use quality Mann, Mahle, Knecht or even Bosch filters before resorting to FRAM...

Third, If you want to use a synthetic, choose one that is the correct viscosity range for your car, and change your oil. Mixing dino (not dyno) oil with synthetic to ease it in is unnecessary...

Finally, follow the directions for your Topsider carefully, remove the oil filler cap before suction, and when done, then open the drain plug overnight, and pump again in the morning (yes, cold). Finally, replace drain plug, replace oil filter and add new oil.

[DEPRIEST]

David,
Scott is right. If you're going to use a topsider, then his way is the way to do it. Now, however you change your oil, just make sure you do it often. Whatever type of oil you're comfortable with, every 3000 miles and your car will do great. (well, do the other maintance and stuff... you know) Just promise us all that you will not run your car with no oil in it. Not even for 30 seconds.
Have fun.
-Kyle

[Southern]

I would never run a car without oil even for 2 seconds. If you are concerned about getting most of the oil out of the engine as you can then I would recommend pulling the drain plug and let it drain out over night.

Yiles! ------- Stop! ------- Don't do it!

David, I read that same book you mentioned in high school, only problem is that that was about 15 years ago. That author had some other unpractical ideas such as driving around potholes to reduce suspension wear.