I have a 1990 190E 2.6L and Everytime I change the oil I am fairly observant of when, how much, etc., etc...Well here are the details:
Oil was changed on 11/9/09 @ 248,946 miles with Mobil 1 fully synthetic 15w-50...total of 6 quarts. Bosch Premium oil filter was used and coolant was also drained and flushed and new Zerex G05 was added.

On 11/19/09 my oil light came on. Mileage is now @ 249,630 miles ( a little under 700 miles were driven) and when I checked the dipstick the oil mark was right at the top of the red plastic tip at the end of the stick. I dont have any puddles of oil in my driveway...maybe a little p/s fluid is all. I just changed my valve cover gasket and bought all new valve cover bolts from MB dealership. I tmay have a small leak at the timing cover which is merely a few drops...I will replace that gasket soon. But does anyone have any idea on what the problem is? Is it just that my car is so old? Why is it consuming so much oil?

Why did you use synthetic oil?

You only burnt through about 2 quarts, not 6.

Using synthetic oils can cause older engines to burn oil. Use Castrol GTX 20W-50.

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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

Valve stem seals. You have an M103 engine, fairly common at your mileage and half your mileage.

Have you noticed any smoking on start up and while driving?

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Allen Kroliczek
Oak Grove Autosport | Oak Grove Autosport
01 G500, 82 300TD, quite a few more.....

Really? Oh wow, I've been running synthetic since I had the car. Ok, I will give that a try. Thanks. Oh one last question: since I will now be topping off my oil....I just rcently added another quart of the fully synth 15w-50, will it be ok to switch to the Castrol now or should I just do it at the next oil change?

Have not seen any smoking whatsoever. When I start up in the morning there is a little steam from the exhaust is all....but now that you mention valve stern seals...what is that and where are they located? Just incase switching to the reg 20w-50 doesnt do the trick or if I actually start having the smoke coming from the car.

You can drain the synthetic out anytime.

The valve stem seals are on in the valve stems. Its a pretty involved job.

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

Good idea, I guess I was just wanting to do what I thought was best by getting the synthetic, more expensive stuff.....guess I was wrong. I actually just found an 8 page list from the manufacturer that came with the car that has all the oils and fluids that MB approves of for the car and sure enough Castrol GTX is on the first page! Thanks 79, I will give it a go once I recoup some more funds....just spent close to $200 for a HID kit which I should be getting shortly.

I have a '93 with 145k and it started losing oil just recently. It had been sitting for around five years in a garage in the south before I picked it up and started driving it. Naturally I began using synthetic when I began driving it, but no problems immediately appeared. Synthetic is just better and I prefer to use it. After about 10k on Mobil 1 10W-30 I found multiple oil leaks around the timing cover and cam seal area. Syn will cause old oil seals to leak, most likely by cleaning the sludge built up from years of dino oil in the engine. However after I fixed the leaks around the front of the engine I haven't experienced any oil use. So the real problem is not the oil, its those old seals. I prefer to fix the old oil seals instead of going the band-aid route and regressing back to dino oil. 3500mi oil changes are inconvenient, less efficient, and just plain old-fashioned. There are synthetic options for older engines, so you might try going that route, or just fix the leak(s). Ultimately the engine will be happier.

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)

It is NOT the synthetic oil. My 300E was burning a quart per 400-500 miles when I got it and it was running on dino, I switched it to synthetic, same thing. It was fouling plugs with oil as well. So I paid the $$ and had the valve stem seals replaced, and it now burns virtually NONE between 4,000 mile changes. I did the oil change on it in July, and it has traveled over 3,300 miles since then....oil level has not changed at all on the stick.

Get those stem seals replaced! And run a good diesel synthetic oil...the M103 loves it. My old stem seals were hard as rock, and probably doing next to nothing. The new ones are made of viton and last longer, and are much softer.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Pull your spark plugs and it should be obvious if the valve stem seals need to be replaced.
You will see a black "soot" type deposits left all over. You may need to pull all 6 because its not always all 6 that are leaking.

I have the same problem on my 260E and I burn through about 1 quart every 200 miles...I am pulling it apart next saturday and fixing it. I will take pictures and make a DIY for it. All you need is a valve spring compressor and the stem seal kit. Its relatively straight forward if you are handy. You'll need a second pair of hands, a kid will do, so he can take out the old seals while the spring is compressed by you. They harden up with age, not mileage. Both of my M103's that I bought have had the problem. They were leaking at 62k miles and I replaced them at 70k and it has not burned a drop since.

When the engine is cold it will smoke "slightly" upon acceleration, but once its warmed up it generally will not unless you floor it on the freeway.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

It's easy to coat and bog down the catalytic converter too when your valve stem seals are leaking. Best to replace them and be done with it.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

precisely why I believe the 'just go back to thick dino' advice is crap

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)

it doesn't matter what oil he uses, the lowly store brand oils are better than what was available back when these cars were sold.

__________________
Allen Kroliczek
Oak Grove Autosport | Oak Grove Autosport
01 G500, 82 300TD, quite a few more.....

Now, if it's a diesel you were talking about, it wouldn't matter so much because one way (15w40) or the other (diesel fuel), it's just fuel to the engine. It all compresses and ignites and propels the car. Maybe you could lean back the IP delivery if you knew you were getting a little enrichment from the valves. But I guess things could get crazy if you bleed too much in through valves, and get a run away.

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Cheers!
Scott McPhee

1987 300D

One interesting thing I read was that synthetic oil was actually invented by the Germans in WWII to respond to the Allied interruption of petroleum supply lines. So its been around a while, with API supposedly approving it in the '60s for use in automobile engines. I use it primarily because 3.5k oil changes are a pain in the ass. One can stretch an oil change interval with synthetic out to 7.5-10k and come out cheaper than using dino at 3.5k even though good dino would be half the price. Given the superior lubrication and the fact that you don't have to mess with it until 10k later it's seems a no-brainer. If you have seals that are borderline you will cause leakage though.

__________________
'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)