Are you in the US? If so, you may have some recourse under the class-action lawsuit that MB lost with regards to engines in FSS equipped vehicles. Your 1998 E320 is so equipped, and I understand it is covered under the additional warranty coverage MB has put in place.

However, your consumption, while very high, may not be "out of spec" enough to warrant coverage. This is a bone of contention, as I understand that MB considers anything below 1000kms' per litre (about one quart per 600 miles) "normal."

That said, your consumption is at about that point. If that much were leaking, I should think it would be easy to find. If not a leak, you'll need to have the engine inspected for sludge build-up, which can cause damage to the top and bottom ends of the engine.

Mike,

Since you did the chain, did you replace valve stem seals as well?

Just wondering, because I noticed that the 560 has started to use some oil. About 1 qt/3k miles. It does weep a negligible amount, but thinking it's time to replace the valve stem seals.

Thanks!

I am in California. I will be bringing down my car tomorrow. What kinda test should I ask for? A comression leakdown test, if that's what it's called. I am aware of the class action lawsuit, so I am worried that I might have oil sludge build up or damaged parts due to early MB recommendation on using conventional oil for 10,000 mile interval. However, I have switched over to the synthetic oil a long time ago. Could my excessive oil consumption be caused by the early MB recommendation of conventional oil?

Just to provide one more data element:
1989 560SL, 150K
1 qt per 3000 miles or so
using 20W50 dino Valvoline, high-mileage engine formula

Wondering... orig. valve stem seals?

Thanks!

>>Just to provide one more data element:
>>1989 560SL, 150K
>>1 qt per 3000 miles or so
>>using 20W50 dino Valvoline, high-mileage engine formula
--------------------------------------------------------------------------------
>Wondering... orig. valve stem seals?

>Thanks!

AFAIK, yes; I have the last PO's records covering about the last five years, and it was mostly oil changes. No smoke, minimal drops on floor of garage.
I'd guess I'll want to do stem seals and head gasket in another year or so; the car will be laid up through Michigan's winter. Running beautifully now, and there seems no reason to rush it at this rate.

Thanks!

Interesting, mine smokes a bit at start-up. Think I'll do the chain/rails and v.s. seals soon. Motor ticks too, so guessing the rockers need att'n. Top ends of these motors are their "achilles' heel". :)

Merc 1,

I replaced my oil filler neck and that solved the oil leaking problem, just replacing the gaskets didn't work. The valve cover is bone dry again.

I change my oil every 6 months (3K miles) with no loss of oil on my 98 E320. I use to use Mobil 1 15W50 in the summer and Mobil 1 0W40 in the winter. Now I plan on using the 0W40 year round. On the 98 E320 the manual states that the engine oil capacity is 8.5 Qts. I found that using 8.5 qts tends to over fill the crankcase with oil expecially when the engine is hot. I've been using 8 Qts of oil which puts the level just under the max level with the engine hot. Keep in mind that there is a 2.5 Qt difference from the min to max level.

Using castrol and valvoline 15x40 in 89 300e, 182,000 miles with no oil loss between oil changes.l

1991 420SEL @ 135+K
 

Using 5K oil & filter change intervals, 8 quarts of Pennzoil LongLife 15W-40 (dino) puts the level square in the middle of the dipstick.

Have never needed to add more between changes as the level always remained well above the low mark.

p.s. 8 quarts between changes is WAY excessive, IMHO, but the oil should never go out of grade because of so much fresh oil being added. I would certainly go with a heavier weight oil than a 0W-30 in AZ.