so, i own a cl55amg and a cl500[both with approx 53,000 miles].

neither car has ever needed an oil top-off between service intervals.

but two weeks ago, running at about 100mph on the hardy toll road, the instrument panel delivered a message. to paraphrase, "needs 1 litre, stop at next filling station".

now, the last change/replenishment of 0/40 mobil one occurred approximately 6,000 miles ago.

i have never seen this message before. and i was curious by the measurement of oil in a european system for a u.s. market car.

and this message would appear routinely over the next 50 miles.

putting the car back in the barn, i let is sit for about 15 minutes, then deployed the electronic oil level sensor. display read "perf".

just to verify that, i thought i might check the dipstick. but i discovered that there is no dipstick. oh, there is a cap on what would be a dipstick receiver, but there is no mechanical method for checking oil level. how odd, i thought.

so i consulted the manual. actually, it shows a dipstick constructed like a string of beads. and what pulled out appears as if the top end of that string. so, i wondered, did all those beads fall into the sump?

then i consulted the manual again, and though a dipstick measurement is referenced, the manual advises that the electronic measurement is more accurate[really?].

putting the car in the barn, leaving it with the electronics that the oil level was "perf", i decided to examine my cl500 to see if it had a dipstick. it did.

i assumed that this was a difference between the cl500 engine and the cl55 affalterbach engine.

on monday, with the cl55 engine cold after sitting for two weeks, i checked the oil level through the electronic measurement system. displayed, "perf".

took it out, then, for a high speed run. below 70, no warning messages. but, during a 70-100 burst, the add 1 litre oil message appeared. hmm.

arriving at my destination, waiting for 5-10 minutes, the electronic sensor reported "perf".

now, i really wanted a dipstick. were the electronics going screwy?

so, i telephoned my dealer's techs. all of whom i have known for decades - the only mechanics that work on my sacco collection vehicles.

while i waited for them, i did the electronic sensor oil level menu again. now it told me that the sump was 1 quart low.

eventually, my tech guru answered his phone and we discussed this issue. though he agreed with me that a dipstick would have been a good idea, one was never fitted by benz for the 2006 cl55.

then he said, in fact none of your 2006 215 series should have a dipstick.

then i said, but you must be wrong, my cl500 has one. so, he said that i must be looking at the transmission dipstick instead of the oil dipstick.

so, i had to remind him that over the years, i have rebuilt many benz engines, and though never a 215 engine, i do know a dipstick tube from a tranny tube.

so then he said a peculiar thing, he said that for the cl500 engine, for $125 a dipstick was available. its level markings were in millimeters, not ozs. and that when fitted by an owner, there was a conversion chart for millimeters to ozs.

i haven't checked out the marking designation for that cl500 dipstick yet.

still would any gurus here care to comment.

all ears