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2003 BMW 325i
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Discussion Starter · #1 ·
My car has gradually gone from 1 qt/1000 miles to 1 qt 300 miles. I got so tired of this I finally got the CCV redone, and topped the oil off (to the top line). My car is now burning 1 qt/250 miles which is ridiculous. I know some people are fine with topping off oil every now and then, but I am having to do it weekly. I don't currently see any leaking oil on or around the block, the oil pan and valve cover gaskets have been replaced. I plan on pulling a spark plug to see if a gasket was messed up on installation. If there is no oil leaking from any gaskets, and I have a brand new OEM CCV, am I looking at bad oil rings? My car has 170,xxx miles on it, it is a 2003 325I, and I am now realizing after reading some forms, that my cats got clogged, presumably from oil, and am now running catless. Is there any hope for me and my empty wallet?
 

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You could try doing the 'o2 pilot mod' to the ccv, cheap easy and worth a try when you start burning a lot of oil. But as above you should be seeing a considerable amount of smoke out the exhaust burning that much, I have some smoke out mine and I burn a litre every 600-1000 miles

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2000 E46 323i, 3.0L and 2.0L Z3's
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When you replaced the CCV, did you check that the oil return tube in the dip stick tube was clear? They often block up. The return oil has nowhere to go, so ends up going up to the inlet manifold.
 

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2003 BMW 325i
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Discussion Starter · #5 ·
When you replaced the CCV, did you check that the oil return tube in the dip stick tube was clear? They often block up. The return oil has nowhere to go, so ends up going up to the inlet manifold.
I had it done through a shop, the invoice says they replaced that hose completely, and for the $50 they charged for it I hope it's clear. I was thinking about the o2 pilot mod, however I feel like at the consumption rate I'm at, it might not do much. That being said, it is cheaper to do and replace every now and then, rather than replacing weekly.
 

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2002 330ci auto
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I had it done through a shop, the invoice says they replaced that hose completely, and for the $50 they charged for it I hope it's clear. I was thinking about the o2 pilot mod, however I feel like at the consumption rate I'm at, it might not do much. That being said, it is cheaper to do and replace every now and then, rather than replacing weekly.
It's not the hose that gets clogged; the metal dipstick tube has a small channel near the bottom where it let's oil flow from the ccv hose to the sump.
 

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I had it done through a shop, the invoice says they replaced that hose completely, and for the $50 they charged for it I hope it's clear.
So you hope it's clear. No, it's time to make sure it's clear or the engine will suck oil and eat it for lunch: at the hose connecting the CCV to the dip tube, remove the end at the CCV, then with the dipstick installed, blow hard into the removed end of the hose and if you hear bubbling then it's not clear.
Edited: it should read if hear bubbling then it is clear.
 

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2003 330cic, 2003 325iT
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So you hope it's clear. No, it's time to make sure it's clear or the engine will suck oil and eat it for lunch: at the hose connecting the CCV to the dip tube, remove the end at the CCV, then with the dipstick installed, blow hard into the removed end of the hose and if you hear bubbling then it's not clear.
This ⬆
It is not intuitive. Pull the dipstick tube and you will see the double-wall. The area between the walls is the drain for the ccv. Very likely it is clogged.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Something to consider. The CCV does NOT plug into anything nor does it have power. Therefore it relies on engine vacuum to operate.

Folks with even small vacuum leaks blame the shitty CCV system. The tighter your engine the better it works.

I would be looking very hard at brand, also the bottom hose and clear ? dipstick.
 

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2001 325ci
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I had it done through a shop, the invoice says they replaced that hose completely, and for the $50 they charged for it I hope it's clear.
you could have mentioned if u supplied parts. the statement "...the invoice says they replaced..." not necessarily suggest. either way, u provided or not, $50 is very cheap. i would be happy to pay that much and provide necessary parts if done right.
 

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2003 BMW 325i
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Discussion Starter · #12 ·
either way, u provided or not, $50 is very cheap. i would be happy to pay that much and provide necessary parts if done right.
I did not provide parts. The $50 was just for that one hose, the whole thing was closer to $500ish (they did some other stuff so that's just an estimate based of a quick glance at the invoice) for the CCV, parts and labor. I just drove home from Birmingham to Atlanta, around 170 miles. Blew through a quart(topped it off when I left, was at the bottom mark when I got here). I had a friend look when I revved it to around 4000. Not a lot of smoke, but some smoke, and oil sprayed all on the ground.
Automotive tire Road surface Asphalt Synthetic rubber Tar

Checked the spark plugs, they were pretty dry, but the piston, from what I could tell, was soaked in oil. Will do a compression check tomorrow. I feel like this could rule out the dipstick, but if the test is fine I will be checking that next. (Perosnally I fell the compression test would be quicker/easier than checking the dipstick as mentioned above, but if you have different thoughts let me know.)
 

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2003 330cic, 2003 325iT
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It is funny how people ask for advice and then ignore it. Dipstick idea may not be right, but it is 20 minutes work to check it

who knows?
 

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2003 BMW 325i
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Discussion Starter · #15 ·
I never said it wasn't a clogged dipstick tube. Imo the dipstick tube is a pain in the ass to get to. I'm not trying to ignore advice, but I will admit it's me being a bit stubborn and having a hard time believing that clogged tube can cause the oil consumption I'm experiencing. I was also planning to do a compression test first anyway, I just wanted advice mainly on what it could be if it wasn't the oil rings/valve stems seals. I know I probably worded it weirdly, but if I'm wrong I assure you I'll let you have the satisfaction of being right if it is the oil dipstick tube and im sorry for wasting your time. I also feel like the combustion test would be most efficient in this scenario, telling me if it's the dipstick tube/CCV/vacuum leak or if it's in the combustion chamber.
 

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2003 BMW 325i
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Discussion Starter · #17 ·
I understand yes, however I would believe that if the dipstick was clogged, it would be at a constant oil consumption rate. My issue with that is, my oil consumption keeps going up. I'm now burning 1 quart every 150 miles, whereas it was 1 quart every 250 a month ago, etc. I'm not that knowledgeable about this, this is just an assumption, so correct me if I'm wrong, but why so set on checking the dipstick??? A compression test is just as quick and if it turns up fine its just another 20 minutes to check the dipstick.
 

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so correct me if I'm wrong, but why so set on checking the dipstick
Because it's the easiest thing to do in this case: just disconnect the CCV drain hose end off the CCV, then blow into it.
Checked the spark plugs, they were pretty dry, but the piston, from what I could tell, was soaked in oil.
This makes no sense, as the spark plug and the piston are in the same combustion chamber, and so if the piston was soaked in oil and so was the plug tip. How do you see the piston top wet with oil?
I had a friend look when I revved it to around 4000. Not a lot of smoke, but some smoke, and oil sprayed all on the ground.
Stuff on the ground is not oil, but just some carbon mixture with water vapor. I see the tail pipes are not wet with oil. Rev rpm up to 4000 then let go the pedal quickly to create suction in the combustions to pull in oil, and see if more blue smoke at tail pipes.
 

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2005 330i manual transmission performance package
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Once an M54 engine gets a signifinant oil consumption for whaterver reason, it tends to get worse - because of the oil control rings.
In your situation, you should make sure the primary reason for oil consumption (if other than the oil control rungs having being gradually gunked up) is fixed, then try to clean the rings with oil flush, then perhaps try the O2Pilot mod, etc.

If you suspect a CCV system failure was what initated this, make sure it is working properly now:

  • correct crankcase vacuum at idle (~14 mbar, or 5" water column).
  • not too much oil in the intake side of the CCV system and the air intake itself.
  • oil draining into the dipstick duide tube, and the guide tube allowing this oil to flow down into the oil pan.

Also check if the fuel trims aren't too far off - this should rule out vacuum leaks messing up your mesurements.
 

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Discussion Starter · #20 ·
Because it's the easiest thing to do in this case: just disconnect the CCV drain hose end off the CCV, then blow into it.
As I said, I disagree.
This makes no sense, as the spark plug and the piston are in the same combustion chamber, and so if the piston was soaked in oil and so was the plug tip. How do you see the piston top wet with oil?
Tip of the spark plug was dry. Shining a flashlight into the hole I can see what appears to be wetness.
Stuff on the ground is not oil, but just some carbon mixture with water vapor. I see the tail pipes are not wet with oil. Rev rpm up to 4000 then let go the pedal quickly to create suction in the combustions to pull in oil, and see if more blue smoke at tail pipes.
The stuff smelled and felt like oil, but I can retry tomorrow morning.
 
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