Mercedes E320 engine light and oil consumption

I purchased a used 2001 Mercedes E320 4-matic that had 70,000 miles on it. This was about three month ago. On the dash there are these great indicators that tell you if you have a malfunction, your average mpg and if your oil is low. It actually measures it and tells you how much you need if any. In the time I have had it, that indicator has gone off twice. Do these cars use lots of oil? I have never had a vehicle use so much. There are no spots on my garage floor so I know that it isn’t leaking and the engine compartment is clean. Also the engine light seems to come on in conjunction with the oil level indicator. Since I have had it the engine light has come on 4 or 5 times but if the car needs a quart the light has turned off by the next day when I turn the car on again. And when the engine light turns on, there is no indicator of what the problem is in the malfunction indicator. Today the engine light went on but the oil indicator said the level was ok.

The car was originally leased for three and a half years so I know it was maintained, I checked it out on Carfax and all of the maintenance notes were there. It did seem to have lots of electrical problems in those notes though. The second owner had it for about two years and in that time they put four new continental tires on it and new brakes, so I would imagine that they also maintained it.

I DO NOT want to take it to a dealer until I have some idea of whats up. I love what you wrote about owning an E 320 here. One of the things I told my husband when I started driving it was that I get the dirtiest looks from other drivers and everyone seems to want to cut me off! Luckily this car has great pick up and no one has been able to cut me off yet. I do notice that I drive much more conservatively in it though.

Thanks for your help.

I don’t where you are located, but it sounds like you need to find someone, either an independent shop or the dealer to read the codes and find out what’s going on. Also, how much oil consumption are you experiencing (i.e., how much oil do you have to add in 1000 miles)?

Welllllll, I know you don’t want to take it to the dealer, but you’ve got two issues going on here that may or may not be related: excessive oil use and the check engine light. The check engine light comes on to indicate there’s a condition in the motor that the computer can’t compensate for or correct. When you take it to the dealer, they’ll connect their diagnostic computer to your car and it will allow them to see just what the car is trying to tell you. Point being, it IS trying to tell you something.

As for the oil consumption, how much is it using? That is to say, how far do you drive between instances of the low-oil light coming on (you’re sure this is the low oil light, and not the oil pressure light?), and how much must you add in that period? You are checking the dip stick to make sure that you’ve not added too much, correct?

Is there an oil dip stick, and did you check it? That would tell you whether the oil level indicator works properly. If you are losing oil, you are probably burning it. Does the exhaust have any color?

No car uses enough oil to require replenishing it between oil changes if the seals are working properly.

I have put over four thousand miles on it and in that time I have put three quarts of oil in it. I live in Wisconsin.

The car has a function that tells you in writing that the oil level is low,not an oil “light” if it were the pressure I would assume it would say that possibly? Since it tells me how much the car needs, I don’t put to much in.

The exhaust has no color at all, not blue as if it were oil, right?

Yes I do check the dip stick also.

Okay, that’s good, but we still need to know how much it’s using and at what rate.

I have had it for about three months. I have put four thousand miles on it and I have put three quarts in it. I haven’t check for mileage when I put the oil in. I also checked the dip stick today. The oil level indicator said the level was ok and the stick had oil in the middle of the acceptable range.I just opened the hood and looked closely with a flashlight and the engine compartment is clean. If the seals were bad wouldn’t there be oil splatter in the compartment?

Using 3/4 quart in 1000 miles is higher than I would expect for your engine, but might be within the high end of “normal.” I suspect you have something going on (like leaking valve seals) that should get some attention.

Who normally services this car? Do you usually take it the dealer or an independent mechanic? If you are not comfortable bring it to a dealer, I would recommend shopping around your area for a good independent benz shop. You need to have someone to perform routine maintenance on this car anyway. Have them check the codes and determine why the CEL came on. Using a “drive it until it breaks” approach is very expensive on these cars.

If there were leaking valve seals wouldn’t there be some kind of oil splatter in the engine compartment? Or at least oil drops on the garage floor? I haven’t taken it anywhere since I have only had it for three months. I do have a mechanic that only services European cars. I just haven’t been there yet.

I guess I should also say that there is no oil splatter in the compartment and no oil on the garage floor.

First of all, do not put a lot of faith into CarFax reports. They are often incomplete and often wrong. CarFax has become big by convincing too many people that they are the final word on a car’s well being and records. This is not the case.

Your oil consumption problem is one that I personally would not be happy with although some may say that is normal useage.
Oil consumption for whatever reason does not mean the engine compartment will be oil splattered or spots will be left.
Smoke from oil burning may not be noticeable because the catalytic converter is catching it.

What should be done first is a leak-down test to determine piston ring condition. This test is not always infallible but it’s the best method available. There is no test for checking valve seals. If in doubt, they must be replaced with a silent prayer.
The mileage on the vehicle is comparatively low so it’s possible that some or all of the oil rings on the pistons could be stuck due to driving habits of the previous owner (as in sludged or carboned up) or they could be stuck due to an episode of overheating in the past. It only takes one running hot bout to ruin piston rings.

As to a Check Engine Light (guess that’s the one you’re talking about) then the codes need to be pulled and those need to be diagnosed.

See OK4450’s post, valve seals are internal to the engine. If they leak, they allow engine oil into the combustion chamber with the fuel/air to be burned. Leaking valves are not an external leak.

Thanks ok4450, your advise is exactly what I was looking for. I didn’t want to go to the dealer and say, “I have no idea what is wrong with my car?!?!?!” At least I can go to them and ask them to do a leak down test to see what condition the piston rings are in. Dealers and mechanics will take advantage of a chick when they walk in and say they have no idea what’s wrong.

Thanks ok4450, your advise is exactly what I was looking for. I didn’t want to go to the dealer and say, “I have no idea what is wrong with my car?!?!?!” At least I can go to them and ask them to do a leak down test to see what condition the piston rings are in. Dealers and mechanics will take advantage of a chick when they walk in and say they have no idea what’s wrong.

Thanks again for reading my posts and giving me great advise.

You can get the codes pulled for free at a local auto parts store. They have OBD-II code readers that you can borrow. You leave a credit card with them and they return it to you after you return the code reader. They will print out the codes and even discuss it with you. They will give you instructions on how to connect it and collect the codes. If you aren’t comfortable doing it yourself, you might take a friend with you who is comfortable doing it. Maybe the folks at the parts store will help collect the codes. All before you drive over to make sure that the store actually has one. FWIW, I borrowed one from Advance Auto Parts.

I don,t think the other drivers want to cut you off they only want to drive by and see the good looking chick in a 320 merry christmas