2002 325i Engine Oil Burning

[stick20]

My 2002 325i burns a lot of engine oil, from max to min level it takes a month (about 1.8k km or 1k miles). Is this normal? My mechanic said there is no leak, and he can't find anything wrong. Any idea why is this happening and how do I correct it?

Thanks.

[Ion Donut]

Do you have any problems with performance or rough idle? the reason I am asking is that one possibility might be the crankcase vent valve - or whatever you call it. I'm sure some one will jump in here and correct me on this one.

If that valve is plugged, you will consume more oil than normal, and to me, about 1 quart per 1K miles is way too much. I do not know how many miles are on your car, but the year (2002) tells me that it is way too early to be burning that much oil due to worn rings or valve guides.

When did you start noticing the problem? How long has it been going on?

[zeekman914]

If I remember right between "min" and "max" is one quart. So 1 qt. per 1000 miles. I think that might be excessive but I am not sure. On some cars that's considered normal. But with BMW I can't recall. Had a hard day at work so im fried. Sry. I can tell you that my car doesn't burn any oil after 5000 miles. BMW usually that 1000 - 1500 miles per quart is not a problem or indicative of a failure. So... I wouldn't worry about it right now. Unless its under warranty then you might be able to ask the dealer to look at it.

[stick20]

It is a little rougher than before when idle... performance wise, I don't feel much difference. The car has <79k miles.
I think it has been about a year now (maybe longer), at first i thought the mechanic didn't put enough oil in when they do oil changes.

[milgravis]

coud be your crankcase vent.valve or CCV-enother name for it. In mi case it was the problem with oil consuption. The valve was cloged-up and rubber hose wich runs from the the bottom of the valve to the deepstick was also cloged with sludge and broken. I changed valve and hose myself, took me 6hr. to do the job,but i,m ok. now.

[Ion Donut]

There is a quick test you can do to check to see if the CVV is working at all, and that is to remove the oil filler cap while the engine is idling. If you get a noisy vacuum sound and, in addition, the engine rpm stumbles quite a bit then the CVV is suspect. If you just get a very slight vacuum noise and no rpm stumble after removing the cap then the CVV is probably OK.

[dawid25]

I had this problem once , this is pcv valve it cost around $45 + mechanic cost .

http://www.autohausaz.com/search/pro...52@PCV%20Valve


good luck

[stick20]

The mechanic reported that the pressure for rings are pretty good (about 2% loss for each). He said it looks pretty dirty looking into the opening. He suggested to do a couple oil changes and flushes in a row. I wonder if that will clean the engine. Someone in another forum suggested me to use auto-rx to clean the engine, wonder if I should give it a try.

[Spacey]

My prelude used to burn about 1-2qt/1k miles

Definitely was not normal. Changed Pistons, and the problem still persisted. Changed the... pcv? ... still wasn't it. Eventually it was something to do with the valves. Mechanic told me, but I forget the exact problem.

[BMWBurnout875]

My prelude used to burn about 1-2qt/1k miles

Definitely was not normal. Changed Pistons, and the problem still persisted. Changed the... pcv? ... still wasn't it. Eventually it was something to do with the [COLOR=blue! important][FONT='segoe UI', verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif][COLOR=blue! important][FONT='segoe UI', verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif]valves[/FONT][/FONT][/COLOR][/COLOR]. Mechanic told me, but I forget the exact problem.

Hondas burn oil like crazy especially when you start getting some miles on that thing....thats normal for every single honda person ive ever talked to =/

[nathancarter]

I agree on the bad PCV (also called crankcase vent valve, oil separator, etc). There is a leak, but it's not leaking to the outside of the engine, it's leaking into the intake (instead of being separated and returned down to the oil sump).

I would definitely start with an oil change along with a usual regimen of good gas (no no-name 87 octane for a few months). I probably would NOT do an oil flush unless you're certain you don't have any other sludge built up in the system. You don't want to flush loose a little blob of sludge, and have it block an oil passage somewhere.

[zeekman914]

Hey nathan, I feel honored that you quoted me in your sig. I don't know if i should or not.

[02E46Black330Ci]

Im having the same problem i just changed my oil 2000 miles ago and i already had to put in a 1 1/2 quarts already and i have a 02 330Ci. i thought that the drain plug was a little loose but i checked and its in there tight as well as the oil filter. but if you find out why its burning so much oil will you pm or email me about it. cause i would love to find out why im spending 12 bucks every month or so on oil

[Kp008073]

Please help me! I have a 2010 328i with 50,000 miles. Today while driving, my car started sputtering as I accelerated and the Service Engine Soon light came on. 2 weeks ago the same thing happened while my husband was driving it, he added 5 qts of oil and everything seemed to be going smoothly until today. We thought it was just out of oil (I'm due for an oil change in 200 miles)... it's sunday so I can't call any shops and its eating me alive not knowing what it could be so I was thinking I could get some advice. Mostly I'm worried about what it's going to cost. I don't know any terminology or anything about cars. Lol.

[SilverSaloon69]

Please help me! I have a 2010 328i with 50,000 miles. Today while driving, my car started sputtering as I accelerated and the Service Engine Soon light came on. 2 weeks ago the same thing happened while my husband was driving it, he added 5 qts of oil and everything seemed to be going smoothly until today. We thought it was just out of oil (I'm due for an oil change in 200 miles)... it's sunday so I can't call any shops and its eating me alive not knowing what it could be so I was thinking I could get some advice. Mostly I'm worried about what it's going to cost. I don't know any terminology or anything about cars. Lol.

What year is your car? If its a 2010, that will change many replies.

[tdileonardo]

Hi,

I have a similar problem in my 2002 BMW 325i . There is 198,000 miles on the motor. I am burning oil on start and upon a shift when sitting idle for a while with a puff of white smoke. I have replaced the valve cover gasket set, spark plugs, CCV and hoses, oil filter reservoir, radiator, coolant reservoir, coolant hoses, and all vacuum hoses. This problem still persists although it does run better. I am now hearing strange sounds from the catalytic converter and the check engine lite comes on. I have been told that this may be the "valve seats" leaking oil into the pistons. I am not sure if it would be better to replace the motor with a used one and transfer the parts I have replaced on to this motor? Is there anything else that could be causing this since (I just replace the CCV)? Should I replace the bottom end with a newer motor with 70,000 miles on it?

[MarcoZandrini]

M54 engines were built with low tension oil control rings.

FYI, there are 3 rings on each piston. The top 2 rings maintain compression. The bottom ring is the oil control ring.

Low tension oil control rings (LTOCR) require that there be a constant crankcase vacuum to operate properly. That's the job of the crankcase ventilation system (CCV). Unfortunately, it seems the engineer who designed the CCV for our engines was an ex-Audi engineer-it doesn't work properly. That's ok for the first 50k miles or so of engine life as the LTOCRs are still fresh and reasonably clean. The problem rears its ugly head as the LTOCRs become carbonized. That is, crap from the combustion process gets by the compression rings and finds a home in the LTOCRs. This is aggravated by the long oil change intervals that BMW used to tout! So, we end up with less than new LTOCRs that are carbonize, and aggravated by an improper and inconsistent crankcase vacuum. This is further exacerbated by short driving trips that don't permit the engine to reach full operating temps (95*C to 100*C via test #7 in the obc readout; ignore the temp gauge as it's controlled by the ECU).

There have been many "solutions" proposed and tried on this and other forums. They are:
- the "Italian" method where by the engine's speed (rpm) is kept at/near redline for a couple of minutes. Results: meh.
- replace the CCV and the dipstick tube. Results: some show a very modest decrease in oil use especially if the old CCV was kaput. My personal results: zip. In fact the oil drain tube that runs from the CCV body to the dipstick tube was DRY, not even a hint of oil!!! See my previous comment about the skills (lack thereof) of the CCV engineer.
- top end soak whereby the ignition coils and plugs are removed and several ounces of AC Delco top end cleaner are poured into each cylinder. The stuph is left to soak for 24 hours. Results: some improvement. It must be noted that removing the carbon from rings WITH THE PISTONS OUT OF THE ENGINE takes a lot of work as the carbon has become baked onto the rings and the pistons. This isn't really a long term solution as the the crappy CCV is still not doing its job (thanks to an ex-Audi engineer).
- adding a vacuum hose that runs from the CCV body to an unused vacuum port at the rear of the intake manifold. This works by increasing the vacuum in the crankcase. But IMVHO is that this may induce oily gases directly into the intake manifold. Why? Because the added vacuum is applied to the CCV body before the CCV diaphragm that separates oil from gas. Some have experienced good results with this solution.
- the oil catch can (OCC) works similarly to the added vacuum line solution noted previously as this solution increases crankcase vacuum. However, it totally bypasses the CCV!!!!! Basically, the OCC solution captures crankcase fumes at the valve cover port previously used by the (POS) CCV system. Those fumes are routed to an oil catch can mounted in the engine compartment, usually in the "drug bin" on the passenger side. The oil drops out the fumes and the fumes are routed to the air distribution manifold that sits on top of the intake manifold. The catch can slowly fills with oily gunk which is then dumped into an oil recycling tank. This solution provides greater and consistent crankcase vacuum while properly separating out the oil. As soon as my thumb heals I'll be installing a Mishimoto OCC in my 2001 330Ci (115miles).

[tdileonardo]

Marco, Thanks for the Excellent information in your post...

Things I have tried:

1. Replace CCV, all hoses, all throttle and intake gaskets, all valve cover gaskets, dipstick and O-rings - This made the vehicle run better but failed to solve the problem
2. Place about an ounce of AC Delco top engine cleaner in each cylinder, let it sit overnight (Maybe I should of let it sit longer?) This created all kinds of smoke for about an hour when started (To be expected). - The engine then sounded different (possibly more in tune) however failed to solve the problem.

Things I would like to try:

1. The oil catch can (OCC). I will look this up and see what it requires, any posted links or information on this would be greatly appreciated.
2. Adding a vacuum hose that runs from the CCV body to an unused vacuum port at the rear of the intake manifold. I know where this is on the intake manifold from taking it apart and installing the CCV. Not sure where the port is on the CCV. The one I bought was the "cold weather version". It may be under the rubber insulation cover.
3. Locate and String up the ex-Audi engineer. This will not solve the problem but will make several other people and myself feel better. This is the true "Italian Method"!

I would hate to put in a new 70,000 mile motor. From the information you gave the it would still be problematic since the Low tension oil control rings (LTOCRs) would be baked with carbon after 50,000 miles. Should I try the AC Delco top end cleaner and let it soak for a longer duration of time?

Your information and expertise is GREATLY appreciated!

Thanks,

Tony

[MarcoZandrini]

I think the AC Delco stuff has an effect but I personally don't think that that impact is very big. I have read posts by engine builders who have spent hours removing the carbon from the piston ring lands (the groove in which the piston rings sit). They have used fluids that are specifically designed to remove the carbon as well as specialized tools. Remember that carbon's cousin is another carbon substance-diamonds!

[tdileonardo]

I think the AC Delco stuff has an effect but I personally don't think that that impact is very big. I have read posts by engine builders who have spent hours removing the carbon from the piston ring lands (the groove in which the piston rings sit). They have used fluids that are specifically designed to remove the carbon as well as specialized tools. Remember that carbon's cousin is another carbon substance-diamonds!

Good Point,

Do you know where to route the OCC hoses to? I am willing to try that for a while seeing as it will at least eliminate some of the gunk and catch more oil. I guess there isn't really any solution to getting the carbon out other than replacing the motor with a completely rebuilt one?

Thanks,

Tony

[MarcoZandrini]

There's a great thread with a video about the OCC on E46Fanatics. Basically, one hose connects to the outlet on the valve cover that is used by the CCV to capture oily fumes. The other hose, the "return," is connected to the air distribution manifold. That's the grey plastic piece that sits on top of the intake manifold. See item #5 in http://www.realoem.com/bmw/enUS/show...diagId=11_2879. There's a connector on the underside of this piece. "Oil" condensates out of the fumes in the can and the fumes are sent to the air distribution manifold for burning.

[Ds325xi]

M54 engines were built with low tension oil control rings.

FYI, there are 3 rings on each piston. The top 2 rings maintain compression. The bottom ring is the oil control ring.

Low tension oil control rings (LTOCR) require that there be a constant crankcase vacuum to operate properly. That's the job of the crankcase ventilation system (CCV). Unfortunately, it seems the engineer who designed the CCV for our engines was an ex-Audi engineer-it doesn't work properly. That's ok for the first 50k miles or so of engine life as the LTOCRs are still fresh and reasonably clean. The problem rears its ugly head as the LTOCRs become carbonized. That is, crap from the combustion process gets by the compression rings and finds a home in the LTOCRs. This is aggravated by the long oil change intervals that BMW used to tout! So, we end up with less than new LTOCRs that are carbonize, and aggravated by an improper and inconsistent crankcase vacuum. This is further exacerbated by short driving trips that don't permit the engine to reach full operating temps (95*C to 100*C via test #7 in the obc readout; ignore the temp gauge as it's controlled by the ECU).

There have been many "solutions" proposed and tried on this and other forums. They are:
- the "Italian" method where by the engine's speed (rpm) is kept at/near redline for a couple of minutes. Results: meh.
- replace the CCV and the dipstick tube. Results: some show a very modest decrease in oil use especially if the old CCV was kaput. My personal results: zip. In fact the oil drain tube that runs from the CCV body to the dipstick tube was DRY, not even a hint of oil!!! See my previous comment about the skills (lack thereof) of the CCV engineer.
- top end soak whereby the ignition coils and plugs are removed and several ounces of AC Delco top end cleaner are poured into each cylinder. The stuph is left to soak for 24 hours. Results: some improvement. It must be noted that removing the carbon from rings WITH THE PISTONS OUT OF THE ENGINE takes a lot of work as the carbon has become baked onto the rings and the pistons. This isn't really a long term solution as the the crappy CCV is still not doing its job (thanks to an ex-Audi engineer).
- adding a vacuum hose that runs from the CCV body to an unused vacuum port at the rear of the intake manifold. This works by increasing the vacuum in the crankcase. But IMVHO is that this may induce oily gases directly into the intake manifold. Why? Because the added vacuum is applied to the CCV body before the CCV diaphragm that separates oil from gas. Some have experienced good results with this solution.
- the oil catch can (OCC) works similarly to the added vacuum line solution noted previously as this solution increases crankcase vacuum. However, it totally bypasses the CCV!!!!! Basically, the OCC solution captures crankcase fumes at the valve cover port previously used by the (POS) CCV system. Those fumes are routed to an oil catch can mounted in the engine compartment, usually in the "drug bin" on the passenger side. The oil drops out the fumes and the fumes are routed to the air distribution manifold that sits on top of the intake manifold. The catch can slowly fills with oily gunk which is then dumped into an oil recycling tank. This solution provides greater and consistent crankcase vacuum while properly separating out the oil. As soon as my thumb heals I'll be installing a Mishimoto OCC in my 2001 330Ci (115miles).

i sent you a PM idk if it went through or not

[maxell0405]

Increasing crankcase vacuum by installing a hose from the CCV to the back of the intake reduced my oil consumption to near-zero from a quart every 2,000 - 2,500 miles. It may work even better than that - I just haven't driven enough miles to say for sure. Here is a huge thread discussing it and including some DIY information. You don't need to read the whole thing if you don't want to; just scroll through until you find the instructions for doing the mod It's simple and it it worked for me.


http://www.bimmerforums.com/forum/sh...onsumption+ccv

[MarcoZandrini]

Increasing crankcase vacuum by installing a hose from the CCV to the back of the intake reduced my oil consumption to near-zero from a quart every 2,000 - 2,500 miles. It may work even better than that - I just haven't driven enough miles to say for sure. Here is a huge thread discussing it and including some DIY information. You don't need to read the whole thing if you don't want to; just scroll through until you find the instructions for doing the mod It's simple and it it worked for me. http://www.bimmerforums.com/forum/sh...onsumption+ccv

The purpose of the CCV is to filter out liquids (oil) and route the remainder to the intake manifold for burning. The problem with this solution is that unfiltered air (i.e., oily crankcase fumes) are being routed directly into the intake manifold. That doesn't bode well for the cats.

[floydr]

...
I have been told that this may be the "valve seats" leaking oil into the pistons...

No-one has yet commented on this. (Likely he meant valve GUIDE seals - if the valve seats or valves were worn it would be pretty obvious due to exhaust pulses and possible back-firing.) The guides can be replaced (might need to pull head).

Did the mechanic do a leak-down test, and a compression test? Results?

It's unlikely IMO that valve guides are your problem (well, they're likely leaking but they always do on this engine), as the evidence of smoke on acceleration indicates compression or oil rings or both. A compression test would indicate it with low numbers, especially if upon squirting in some oil brings up the compression.