2003 325 XiT High Oil Consumption

[MajnoLo]

Hi there. About 265,000 miles on my 325 XiT wagon. Going through a quart of oil every 300-400 miles or so. Seems to have started sucking oil rather suddenly - didn't ramp up slowly. Used to be 700-900. There is no visible white smoke. There are no puddles under the car or visbile leaks. I did a little research and am told it could be stuck oil rings (put something in the oil to hope they unstick - SeaFoam??), or possibly the CCV valve (big job to replace), or....??? Would love any advice as to what could be causing this and how to remedy.
Thanks!

[dworthy]

If you have no visible leakage, then it has to be one of the following:

1) Bad rings, this can be oil or compression. You can use some old school ATF to clean the rings out by adding a quart to the oil then let it clean out the system. This is a slowish cleaning so it may take a quart or two.
2) CCV is Bad. Since you live in a rather cold area, I would recommend the Cold weather CCV. Yes the CCV is a PITA, might just as well as replace the upper/lower intake boot while you are at it since you have to remove them anyway. Also if you don't know if they have been replaced, just do it.
3) Bad Valve stems. While not very common on the M-5x motors, it can happen. This would be the last on my list.

I would go in order, but do take the belly plates off and have a look for leaks.

[MarcoZandrini]

I’m betting the CCV is bad. Rings typically go bad over a period time. I think what’s happened is the temperatures have gotten low and the gunk in the CCV body is solidifying. It’s time for a new CCV and hoses, and new dipstick seal ring.

The hard part of replacing the CCV is connecting the new hose that runs from the intake to the CCV body. It’s a twist connection and not a click connection. Search E46Fanactics in how to change the CCV. Also, the dipstick needs to be thoroughly cleaned as the area when the CCV drain connects to the dipstick gets clogged.

I recommend you replace the CCV ASAP as the temperatures in your area are getting colder. A blocked CCV can damage the engine.

[MajnoLo]

thank you for the info! I am quite handy but every YouTube video I see about the CCV starts with "this is a pain in the butt"... How much time would a first-timer expect to take? I am thinking remove the intake manifold since that seems to be the most effective way to go about it... Is this 4 hours? A day? Might be inclined to have my local shop do it... On the fence... Thanks!

[dworthy]

Well I would say about 5 hours to ensure you have enough time and don't feel pressured to get it done right away.

When I replaced the CCV in the wagon, I was in part of the "10 year" service so I was removing quite a bid of stuff anyway.

No, you don't have to remove the intake, just takes some flexible fingers and some imagination. I replaced every hose and the dipstick tube to the "upgraded" version. IIRC having the throttle body out of the way really helped out.

[MarcoZandrini]

To add to what Darin has written, the truck to getting the hose that runs from the intake manifold (air distribution manifold to be precise) is to:
- tie a 2 foot long piece of string to the top of the hose
- push the top of the hose down between the intake runners
- tie the string on the oil fill cap
- position the CCV body in its final position
- rotate the CCV body so that the bottom of the CCV body is point toward the engine
- force the bottom end of the hose towards the CCV body with a screwdriver so that the hose’s connector and the corresponding connector on the body mate
- rotate the CCV body so that its bottom is pointing towards the ground
- pull the string to pull the hose up and into position.

HTH. YMMV.

[MajnoLo]

thanks again. I have decided to go the easy route first, and defer the CCV work until I have to. Note that I warmed up the engine and removed the oil cap slowly - there was little or no hiss or suction, so it seems that the CCV may not be bad (yes?). I am thinking perhaps stuck oil rings - so I put 1 quart of Marvel Mystery Oil in the engine, a second one soon, and see what happens. If all else fails will do the CCV... Thanks for the tips! (love the string thing haha...)

[dworthy]

If the CCV is working properly you will get a SES light on for the oxygen sensor if the oil cap is left off too long. Now the only way to properly test the CCV is to use a slack tube manometer. The vacuum is read in inches of water, and a normal CCV will pull 3-6 inches of water.