Uses ALOT of oil......
 

Hi all, I have an 04 E320 4Matic wagon that really likes oil! We recently took a trip to Texas from Virginia. The total round trip milage was just about 3400. during that trip I added 4 quarts of oil. The car has 84k on it with religious oil changes/maintenance. now a fair amont of the driving was arounf 80 mph which puts the revs about 3100 so maybe it;s burning more at that speed? there are no visible huge leaks even under the lower covers. I use Mobil 1 0W-40 and a factory filter. any thoughts? Thanks in advance.

1 quart every 1k miles is still somewhat within "okay" (but not very cost effective.) But if you get towards 1 quart every 500 miles, then you've certainly got issues.

If you've ruled out leakage, then it sounds like the valve guides are wearing and it's using oil. You can get a compression test done and if all cylinders are low, then it's the rings and cylinders that are worn and it's using oil.

Excessive oil pressure can also force oil into the cylinders.

Keep an eye on the consumption from now on and see how it goes. A top end job (if it's the guides) would be your decision, given the mileage and age. Also you can just keep feeding it oil until you either pollute too much and/or spend too much.

3400 miles at 80mph for most of it, sounds like it would use more oil .. higher rpm = more heat = more oil consumption.

I guess what you need to see is usage for regular day to day driving?

I agree that the OP should monitor daily usage under normal driving conditions. But I'd disagree about driving at a consistent high speed will necessarily consume more oil. But it would depend on the viscosity of the oil you're using. If the oil is too volatile, then like any liquid it will evaporate. Lower viscosity has a higher volatility. So if you're using too low a viscosity oil, you'll get what appears to be excessive consumption, when it's really evaporation. If you're not using the proper oil, then that could happen. But it's rare at that amount (4 quarts in 3.4k) and especially with modern multi-grade synthetics, their volatility is pretty low.

These cars are made to cruise at high speeds on the freeway. In fact, my oil temp is towards the lower end of normal when cruising steadily at 80-90 in 7th gear. If the engine is tight, it really shouldn't use much oil at all.

You may want to draw out a sample of the oil and send it to a lab for analysis to see what's going on in your crankcase as well as seeing how the oil is holding out.

Regards,
paul...

No matter what the driving conditions were and no matter what the speed the consumption that the OP reports is way excessive. I have never had to add a drop of oil between changes to any of my last 7 MB's. And for the person that said high oil pressure creates more consumption, you are way wrong. Not so!!
There are a number of things that could cause this consumption. I would look at the easiest first like valve seals. Also does it smoke at all?

You have a serious problem.

If the oil isn't leaking it is being burned and going through the cat's. This will eventually give the cat's and / or O2 sensor issues.

Time to look closely at the engine.

I have seen on other cars with failures in crankcase vents causing pressure in the crankcase resulting in high oil consumption.

If not a vent issue time for the old fashion wet/dry compression test/leakdown cylinder test.

Engine or valves.

Have you been using approved oils in the engine. This sounds like an engine that might have been serviced with a non MB oil.

It sounds like you have some serious work ahead. I would not expect more than 1 qt / 3000 miles of highway driving oil consumption.

Best of luck

thats a lot of oil to be used in such a short interval

I’m sorry to tell you that you have a HUGE issue. The good news is that the engine WILL keep on running like that for a long time (as long as you keep it filled). The bad news is that something is wrong. When this V6 first came out in 1998 and has the extended oil change intervals, people used organic oil instead of synthetic. If you drove these engines with organic oil for over 9k miles between changes you would develop the problem you just described.

Mercedes first stated that 1 quart per 1k miles was OK, well this was all BS, since this would mean that if you follow the 13K oil change interval, you would have already put an extra 13 quarts of oil in to keep it full. What is wrong with this picture? Well, Mercedes then rebuilt a lot of engines free of charge. This engine is apparently strong enough to have bad oil in it for long periods of time and the only symptom is oil consumption instead of part failure.

I sure hope you have an extended warranty and that you can convince the dealer to fix the issue. It sounds like that engine had organic oil in it. I am about to hit 60K miles on my 04 E320 and I have yet to ever put a drop of motor oil in it between changes. I have gone as long as 14,000 miles on one oil change, got the oil tested and I was told that the old oil was still within specs. So I can tell you for a fact that the 320 engine does not normally burn any oil (even after 14k miles). BTW, I drive a lot faster than 80 and I go over mountain passes all the time, the engine gets worked in my car.

Good luck!

Steve

I was trying to be a little more suttle when I asked about using only approved oils. But you are correct if conventional oil was used and run 13,000 miles the damage has been done, and only rebuild/replace will return the engine to the normal oil consumption.

From a MB I would expect not more than 1qt in 5000 miles. Mine at 94,000 never has oil added between changes and I do change at 13,000 miles with ONLY MB fleece filters and 229.51 oils M1 0W40 European Formual.

Wow, thanks for all the insight although somewhat of a bummer. Unfortunately I purchased the car used but it did have up to date service records. It has appearantly always had Mobil 1 0-W40. Well next step will be a wet/dry compression test and a thorough check for leaks. Wish me luck!

Sounds like your valve gasket is toast....same thing happen to my 5000 using alot of oil...after taking it to MB Chicago they found the issue and since then I never had any problems or oil usuage issues.