oil consumption rate extremely high?

[5TAR5CR3AM]

Have any of you experienced increased oil consumption rates while only driving on the highway? I made the switch over 5000 miles ago to Mobil1 0w40 however I had this problem with the 10w60 as well. Within the past 500miles of all highway driving I have had to add 2 liters, at separate times of course (1 liter each time). This has been an on going problem though, not just within the last 500 miles.

Now when I drive on the highway I usually cruise between 70-80, which is between 2800-3200rpms (6MT). The consumption rate goes through the roof if I stay steady at this speed. To give an example my oil meter can read at the full line at the start of a 100 mile trip. At the end of said trip it would be reading at the 3/4 mark or even the 1/2 mark.

Now driving around town, and short spirited runs I never have to add oil, ever. I do drive the car hard including redline pulls in 2nd, 3rd, and 4th as well as pulls in 5th and 6th It only consumes oil when I cruise at a steady pace.

Obviously I'm a little concerned about this, especially with all the bearing talk. Could it possibly be a worn bearing or perhaps something else internally that could cause the motor to eat this much oil while at a consistent rpm range for a decent amount of time?

There are knocking noises at certain rpm's while under load, but I chalk these up too my cheap ebay catless exhaust. After I installed the exhaust is when these noises became present.

Car has 37,000 miles on it, not under warranty.

[TommyLights]

I have the same issue on the highway, 45k on mine.

[thekurgan]

How much residue is on the exhaust tips? Are you sure it's not a failing oil level sensor? 2 liters in that time period seems really high.

[to///m]

I definitely noticed an increase in oil consumption when I made the switch from 10w60 to M1 0w40.

At 46,000 miles I switched to M1 then by 48,500 I've already added 1.5 qts... and most of my driving is city (but I have done a lot more highway recently thinking about it)

Made a post in another thread and a member said that when switching to a lighter grade oil, consumption usually increases and it wasn't of concern. Have you changed your oil going from M1 to M1 yet? If not, I would soon because I believe the 0w40 should be changed around the 5-7k mile range. See if you continue to burn oil rapidly after you change. If so, then maybe dig deeper... just my advice, I'm no expert, its just what I'm going to do...

[s85e90]

BMW threshold is a qt every 1500 I believe so yes you have a problem

[coloradoe92m3]

Weird as usually its higher revs causing usage. So think of causes of steady, lower flow oil at low ROMs would cause oil loss. Obviously any kind of leak.. take spark plug out. That says a lot. Otherwise I can't think of anything that causes usage more so at steady highway. Id it significantly worsened on thinner oil than probably failing piston rings

[M3PO]

I just switched to M1. With TWS, I would put in 1/2 qt at about 6K miles, then change at 8K miles. So far on M1, the light has already come on once at only 2.5K miles....

[m3ray]

Makes perfect sense that a thinner oil would be prone to burn. Easier to slip pass the rings. I am sticking to 10w 60

[coloradoe92m3]

Right but why more at highway? Maybe its purely the miles is so much more. Equal miles of short trips would be even worse. Yes thinner oil goes by less snug rings

[1sikbmr]

Do you notice any oil spots where car was sitting for a while? Or is there oil coming out of your exhaust? That is a large amount of oil to go through!

[PandaM3]

I listened to a smoking tire interview with Steve Dinan. He said that the M3 has harder piston rings that are thinner so that it expands at high rpm's. If you don't visit the high rpm's on a regular basis... The piston rings stiffen up more and oil starts flowing past them.

For example I used to commute 100 miles round trip, freeway, steady speeds to save gas... And I was having to add a quart every 1500 to 2000 miles.

Now that I have a multinodal folding bike/ train commute... The m3 is used for fun on the weekends which means I'm not concerned with saving gas so as soon as the engine is warmed up I let it rip to 8,000 regularly... So far almost 2,000 miles and I'm only down 1/2 a quart.

Still... If you're burning 1qt every 500 miles you need to find where the leak is... That's excessive

[coloradoe92m3]

There is no magic rings. In general BMW uses relatively loose piston rings to minimize friction and hence will allow oil to escape. However it still males no sense the rings would be designed to tighten up at high rpm where more friction is hugely power robbing. I still don't buy steady highway driving is ever worsethan high rpm driving

[s85e90]

I just have been driving 350 mile round trips for the past few weeks and notice the car using ALOT of oil; however, don't add right away as sometimes the next day the gauge will come up a little. This is probaly due to a few things:

1. At sustained highway speeds the car is running optimally, evaporating off any water accumulated from short trips w/in the oil and this also may be why the next day the gauge goes back up slightly after sitting.

2. At sustained highway speed the car is drawing a decent amount of vacuum and in my case (sustained 80 mph for 2 hrs straight) the car is sucking/creating a vacuum of the oil through the PCV system into the intake and through the motor.

I am gonna pull my intake/filter to check to see if there's more oil than normal in there as I just got back from doing 350 miles.

[5TAR5CR3AM]

Ok, first off thanks for the help and suggestions guys! I did just noticed that I made a mistake I meant I was adding 1 liter every 500 of highway, not 2 liters every 500. Sorry for that mix up.

Also the engine only eats oil once I am on the highway for extended periods and cruising at more than 3000rpm. I can make a dozen short trips (20-30 minute drives, varying rpm's and speeds) resulting in hundreds to a couple thousand miles and the oil level will not change at all. I do daily the car right now.

To answer some of the questions, I do regularly take it to redline. I did notice the rate of consumption increased with the switch to the M1 0w40, but that was to be expected. IT did this with 10w60 too. My exhaust isn't oily, besides normal black residue that results from a catless exhaust on an internal combustion engine lol. There are no oil spots on the garage floor or in any parking space, so I do not believe it is leaking oil. If the oil sensor was failing, then my engine would be flooded with oil by now and I definitely would have noticed.

I'm a little over 5000 miles. I'm changing the oil this weekend or sometime next week. Also ordering an analysis kit. I will also pull the plugs tomorrow and check things out. Not really sure what I should be looking for so if someone could chime in here, that would be great.

[5TAR5CR3AM]

Originally Posted by s85e90

I am gonna pull my intake/filter to check to see if there's more oil than normal in there as I just got back from doing 350 miles.

This sounds like a good idea. When I pull the plenum to pull the plugs I will check it out for excess oil as well as all the other parts of the PCV system.

[Dave07997S]

Originally Posted by s85e90

BMW threshold is a qt every 1500 I believe so yes you have a problem

I read it was every 750 miles...

[5TAR5CR3AM]

So which is it? 750 or 1500?

[Time Lord]

On both of our M3's we go between oil changes 5000 miles without needing any oil. Yours Has to be leaking somewhere or maybe it's natural. These engines are weird

[thekurgan]

Or the sensor is erroneous. The reason I replaced mine was that every 2 or 3 weeks, it would show overfilled, then under. I would have killed the thing if I listened to the under warning.

[s85e90]

Originally Posted by Time Lord

On both of our M3's we go between oil changes 5000 miles without needing any oil. Yours Has to be leaking somewhere or maybe it's natural. These engines are weird

Cars should use oil. Nothing wrong with that

[ruff1017]

That seems high oil consumption.
Mine is 09 and never had to put any additional oil between the oil changes yet.
(Long hwy trip or the dynamic driving)

OP, What is your oil temperature reading while you are doing the hwy trip?

Also check your oil cooler or the radiators to make sure that you do not have debris blocking them.

[Beemdog]

Originally Posted by ruff1017

That seems high oil consumption.
Mine is 09 and never had to put any additional oil between the oil changes yet.
(Long hwy trip or the dynamic driving)

I agree. More than a quart every 1500 miles would worry me even on this engine, which is OK with some oil consumption. I would think that high level of oil usage would show up on the sparkplugs and possibly in the exhaust if someone were to follow closely and watch for blue smoke under various conditions. Also, on other cars I've heard of soot build-up in the exhaust clogging the cats to the point they needed replacement.