Oil Level Strangeness - Please Advise! - PeachParts Mercedes-Benz Forum

dkr · #1 03-26-2016, 04:50 PM

So, yesterday I did an oil change with my topsider (it sucks the oil out of the dipstick), changed the filter and added new oil. With a cold engine, the oil was just above the low mark. I turned the engine on, let it idle for a while, and then drove it around the neighborhood until it was at operating temperature and then checked the oil level again. It wasn't even on the dipstick! It was rather strange as there are no signs of oil leaks anywhere.

After sitting overnight, I checked the oil again and it was way full on the dipstick. I drained about 2-3 quarts out, checked it again on the dipstick -- it was about halfway -- and drove it around just to get it up to operating temperature. Once again, it was very low on the dipstick although it still did register.

I then added about a quart of oil and it got up to high operating range. So, I turned the car on, let it idle for about 15 seconds, turned it off and then checked it again. The oil had visibly dropped on the dipstick. I am very confused here as I have done this process many, many times and not seen this before.

Here are some additional notes:

- Car is relatively low mileage -- 1984 300D OM617 completely stock -- (under 150K and has been very well maintained).
- I check oil levels religiously every time I fill up and I generally add about a quart between oil changes.
- On the last oil change, I did a UOA (Used Oil Analysis) and it showed practically no wear.
- I put in a brand new OEM oil pan and an OEM skid plate, so my oil pan is not dented.
- My oil pressure appears to be normal and engine is running normal.
- There are no visible leaks. The oil cooler lines were recently done and are completely dry on all four connections.

I have a pet theory on this but it doesn't entirely explain where the oil is going between starting cold and getting to operating temperature. I have not driven this more than what is necessary to get to operating temperature, so it may behave differently if I were to drive it on the freeway for a while.

Can anyone explain where my oil is going and if I should be concerned???

Thanks,

Dkr.

toomany MBZ · #2 03-26-2016, 04:52 PM

How much oil did you put in?

dkr · #3 03-26-2016, 05:06 PM

Sorry, that would be important. I put in about 1.5 gallons the first time as usual and then added almost another gallon and then drained about half of that the next day. I have no doubt it has sufficient oil in there (somewhere in operating range), I just can't explain this wierdness or whether I should be concerned about it.

The topsider generally doesn't pull the oil out of the oil cooler, so a bit less goes out and comes back in.

Dkr.

toomany MBZ · #4 03-26-2016, 06:04 PM

The oil capacity is 7.9 U.S. quarts, as you mention, not all of the old oil will come out.

Once warmed up, give it a minute or two for the oil to settle in the pan.

babymog · #5 03-26-2016, 06:18 PM

The topsider pulls as much as draining the pan on a 603, provided a 617 dipstick tube lands at the bottom of the pan, it should also drain the pan completely (just like pulling the plug).

Palangi · #6 03-26-2016, 08:49 PM

I used to have an Isuzu diesel pickup that would occasionally hide oil like that. Never did really figure it out, other than it seemed to happen more frequently when using Mobil Delvac oil. On that particular engine model, it was known that cold oil would be slow to drain down from the top end, as there is no timing chain opening for the oil to drain quickly.

tyl604 · #7 03-26-2016, 09:13 PM

Why not just check it cold for three mornings in a row and see if it is consistent.

dkr · #8 03-26-2016, 10:15 PM

Quote:

The topsider pulls as much as draining the pan on a 603, provided a 617 dipstick tube lands at the bottom of the pan, it should also drain the pan completely (just like pulling the plug).

Theoretically, yes. But, I can't figure out why it isn't. It sucks when it's done like when you're finished off with a slurpee or smoothie. There isn't much still down there in the pan.

Quote:

I used to have an Isuzu diesel pickup that would occasionally hide oil like that. Never did really figure it out, other than it seemed to happen more frequently when using Mobil Delvac oil. On that particular engine model, it was known that cold oil would be slow to drain down from the top end, as there is no timing chain opening for the oil to drain quickly.

Interesting. I used a 15/40 brand I have never used before this time. Perhaps that had something to do with it.

Quote:

Why not just check it cold for three mornings in a row and see if it is consistent.

It had been cold for two days in a row, so it seemed pretty consistent with what it was doing.

Just to update: I just bit the bullet and drove it for ~20 miles today. I was pretty confident it was in operating range with oil, wasn't leaking and had good oil pressure. The oil did eventually show up hot on the dipstick exactly where I thought it would be...

Dkr.

whunter · #9 03-26-2016, 10:25 PM

Quote:

Originally Posted by dkr

So, yesterday I did an oil change with my topsider (it sucks the oil out of the dipstick), changed the filter and added new oil. With a cold engine, the oil was just above the low mark. I turned the engine on, let it idle for a while, and then drove it around the neighborhood until it was at operating temperature and then checked the oil level again. It wasn't even on the dipstick! It was rather strange as there are no signs of oil leaks anywhere.

After sitting overnight, I checked the oil again and it was way full on the dipstick. I drained about 2-3 quarts out, checked it again on the dipstick -- it was about halfway -- and drove it around just to get it up to operating temperature. Once again, it was very low on the dipstick although it still did register.

I then added about a quart of oil and it got up to high operating range. So, I turned the car on, let it idle for about 15 seconds, turned it off and then checked it again. The oil had visibly dropped on the dipstick. I am very confused here as I have done this process many, many times and not seen this before.

Here are some additional notes:

- Car is relatively low mileage -- 1984 300D OM617 completely stock -- (under 150K and has been very well maintained).
- I check oil levels religiously every time I fill up and I generally add about a quart between oil changes.
- On the last oil change, I did a UOA (Used Oil Analysis) and it showed practically no wear.
- I put in a brand new OEM oil pan and an OEM skid plate, so my oil pan is not dented.
- My oil pressure appears to be normal and engine is running normal.
- There are no visible leaks. The oil cooler lines were recently done and are completely dry on all four connections.

I have a pet theory on this but it doesn't entirely explain where the oil is going between starting cold and getting to operating temperature. I have not driven this more than what is necessary to get to operating temperature, so it may behave differently if I were to drive it on the freeway for a while.

Can anyone explain where my oil is going and if I should be concerned???

Thanks,

Dkr.

On the OM616 and 617:
The only accurate oil level check is after at least 12 hours (not run) on level ground.

A warm freshly run engine dip stick should show between 1 and 1.5 quarts low on the average OM616 and 617.

Over filling a warm engine up to the full mark can cause a runaway.

Run away diesel, why does it happen?
Run away diesel, why does it happen? - PeachParts Mercedes ShopForum

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leathermang · #10 03-27-2016, 12:53 AM

Perhaps your drain inside the middle tube in the oil filter is clogged..
or the rubber o rings let the oil drain out of the filter canister some days but not others...

mannys9130 · #11 03-27-2016, 03:07 AM

What you should do for your oil change:

Start the engine and drive around to warm the oil. Park it, shut it down, wait 5 minutes. Undo the nuts on the oil filter canister cap and remove it to let the oil drain out of the canister. Hook up your topsider and start sucking. Replace the two O-rings (every other oil change is OK) on the oil filter canister stem, replace the large cap O-ring, lubricate both with a small amount of oil, replace the filter, and reinstall the canister cap and tighten down the buts evenly. When your topsider is totally done sucking, fill in ~80% of the listed capacity. Start the engine, make sure oil pressure comes up, check for leaks, shut the engine down, and wait 5 minutes. Get the level to halfway or 3/4 of the way on the dipstick, and check it again in the morning after it has sat. At that point, you can get it up closer to the max level but don't go over the maximum mark. You should always check the level each morning for a few days after the oil change to make sure you're problem free.

I think you have old leaky canister stem O-rings that are leaking a quart into the pan overnight. I think you probably put too much oil in to start with. I also think you aren't allowing adequate time for the oil to drain back into the pan. 5 minutes should be adequate.

The level will increase when it's hot. You get the most accurate reading in the morning, but the oil is cold. For that reason, it's safest to not fill it cold up to the maximum mark. That allows for expansion at operating temp. There's 1-2 quarts in circulation at any given time, perhaps 3 at high RPM. Being 1 quart low won't cause harm, but it isn't good. Being off the stick is bad.

Try this measuring technique and report back. Also let us know if you replaced the oil filter canister stem O-rings.

whunter · #12 03-27-2016, 04:49 AM

Quote:

Originally Posted by mannys9130

What you should do for your oil change:

Start the engine and drive around to warm the oil. Park it, shut it down, wait 5 minutes. Undo the nuts on the oil filter canister cap and remove it to let the oil drain out of the canister. Hook up your topsider and start sucking. Replace the two O-rings (every other oil change is OK) on the oil filter canister stem, replace the large cap O-ring, lubricate both with a small amount of oil, replace the filter, and reinstall the canister cap and tighten down the buts evenly. When your topsider is totally done sucking, fill in ~80% of the listed capacity. Start the engine, make sure oil pressure comes up, check for leaks, shut the engine down, and wait 5 minutes. Get the level to halfway or 3/4 of the way on the dipstick, and check it again in the morning after it has sat. At that point, you can get it up closer to the max level but don't go over the maximum mark. You should always check the level each morning for a few days after the oil change to make sure you're problem free.

I think you have old leaky canister stem O-rings that are leaking a quart into the pan overnight. I think you probably put too much oil in to start with. I also think you aren't allowing adequate time for the oil to drain back into the pan. 5 minutes should be adequate.

The level will increase when it's hot. You get the most accurate reading in the morning, but the oil is cold. For that reason, it's safest to not fill it cold up to the maximum mark. That allows for expansion at operating temp. There's 1-2 quarts in circulation at any given time, perhaps 3 at high RPM. Being 1 quart low won't cause harm, but it isn't good. Being off the stick is bad.

Try this measuring technique and report back. Also let us know if you replaced the oil filter canister stem O-rings.

For a w201 chassis 5 minutes is adequate, for the older engines my previous directions are correct.

The 1983+ 190D 2.0L, 2.2L, 2.5L = OM601 engine, and 1985+ 2.9L OM602 engine are ten+ years design/engineering advanced over their predecessors, and where considered a radical change.

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nelbur · #13 03-27-2016, 05:08 PM

This is a guess, but since some Mercedes engines have a dip stick tube that goes down to near the pan, when you check the oil level on the stick, you are actually reading the level in the dip stick tube. That would be the same as the level outside the tube UNLESS the O-ring at the top of the tube seals good and traps air in the tube. When you push the stick down the air might displace the oil level in the tube making it read low. Removing the o-ring would solve the problem temporarily, but there would be nothing to hold the stick in place. The next time you change oil take the o-ring off until you get the oil level right, then put the o-ring back on.

mannys9130 · #14 03-27-2016, 07:24 PM

Roy, that's true, which is why subsequent checking the next morning will allow you to get the level adjusted more precisely.

Junkman · #15 03-27-2016, 09:03 PM

My SDs always read low after starting then stopping and checking the oil. I drain for a long time when doing an oil change. When refilling, I'll leave a 1/2 quart extra in the jug, drive the car then top off the next morning.

I schedule an oil change before winter sets in so that it will last until Spring. Full synthetic lets the engine spin fast enough to start reliably in the winter.