oil "usage" ??

[Todd W126]

1990 420 SEL, Oil changed @ 113,7xx, started trip at 114,4xx, now at 115,5xx or thereabouts.

Just did a thousand mile trip of turnpike driving ( 500 ea way). Ran anywhere between 74-100 MPH ( avg 75-78 or so) and each leg was about 7.5 hours of continuous driving both ways with a day of local driving in between. Checked the oil after initial leg and it was in between MAX and MIN marks. Upon completion of return trip, it's now on MIN mark.

Two questions:

Is that "normal" for it dip that much or should I be on leak lookout?

Also, when it's on the MIN mark, how low is it?

Cheers, Todd

There is an approximate 2qt difference between the two red marks.

Did you check your oil in the same way both times (hot or cold engine), and on level ground? Makes a big difference.

[dpetryk]

These engine tend to use oil because of valve stem seals. Both of my cars used a quart every 700 to 1k miles. I replaced the valve stem selas and the consumption went to zero in both cases. They also needed front main seals as well but the majority of the consumption was thru the valve stem seals.

I would recomend changing the valve stem seals and then checking your consumption. Valve stems are not very expensive. At your mileage its doubtful that the heads need to be reqworked.

[blackmercedes]

A litre of oil in 1600 kilometers (about a quart in a 1000 miles) is not terrible consumption. I wouldn't get to worked up about it. You could do the seals, and that would probably reduce it greatly.

Are the plugs fouling?

Our 1990 190E 2.6 uses a litre every 1500-2000 kilometers in heavy city driving in hot weather (uses less in cooler/highway conditions). The plugs aren't fouling, so I'll just leave it be. That engine has about 200,000 miles.

[Todd W126]

Thanks for the tips/info fellas. Plugs aren't fouling and when I checked it again today, before adding oil, it was higher than before. I called my mechanic and he said I prolly didn't let the oil settle back into the pan when I checked it the first time. He basically said "don't sweat it", especially if I was "hot footing" it ( I was ) during the trip. He told me that I had one of the tightest motors he's seen for a car with my mileage. I added 1/2 a quart and it's back to just below the max mark on the dip stick.

Life is good.

I have this old Greek guy for a mechanic. This guy knows Mercedes inside and out. I woulden't be surprised if he could disassemble and reassemble my car in his sleep with no problems! He tells me that even when my 1987 420SEL was brand new it would burn about a quart of oil about every 800 miles. Hope I can help?

LOL. Your greek friend isn't very bright if he thinks a brand new (after break-in) 420SEL burned a qt every 800 miles. I had an 86 420 that burned about a qt every 1500, with 160,000 on the clock.