1995 BMW 740i E38 Burning Oil, Smoke coming from Exhaust

[diefncy]

My '95 740i has been drinking oil for the past few months, I get a great big plume of smoke when I start it in the morning, sometimes. Or when drive it then park it then drive it later.

I have been looking through forums to find that it might be an OSV issue? I'm not too sure though and would like to take care of this issue as it's annoying to top off oil every 1-2 weeks.

Additionally, my mechanic said the only fix would be to rebuild the engine or replace the engine. How reliable is that suggestion?


Any help would be greatly appreciated!

[clarkitect]

First of all, thanks to Timm for everything I will reference here...

Replace or rebuild the engine: Bad suggestion. I doubt the engine is bad, it is more likely either the CCV located at the back of the intake, which is pretty easy to replace, or it's a problem with the OSV behind the timing chain which is much more difficult to replace IF it needs replacement.

Here's the difference between the two:
http://www.meeknet.co.uk/E31/BMW_M60...entilation.htm

You could start with the CCV.
http://www.meeknet.co.uk/E32/PCV/Index.htm

If it still smokes, then you need to look at the OSV. A common problem is that the drain line gets plugged and allows oil that was supposed to have been separated and deposited back into the oil pan to get sucked up to the CCV and into the engine at start up. You can remove the oil pan, and run some string up the drain tube to start to clear it out. You can also backflush with some kerosene to remove a lot of the crap in there. Here's what it looks like on an M62TU during the backflush (enema) procedure.




Doing this MIGHT help unless the OSV hose between the main body and the top connector has dried up and disintegrated. In that case, you need to get in there and replace it.

[diefncy]

First of all, thanks to Timm for everything I will reference here...

Is there any way you can provide me with links to the CCV and the OSV? I'm quite a noob when it comes to stuff like that. Thanks!

[4liter]

May as well replace the intake gaskets as well because it's easier (from my experience) to pull off the manifold to replace the CCV. Check YouTube, there are loads of DIY to get it done pretty easily.

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[georgebest]

May as well replace the intake gaskets as well because it's easier (from my experience) to pull off the manifold to replace the CCV. Check YouTube, there are loads of DIY to get it done pretty easily.

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While I totally agree...that's when you end up spending hundreds on parts cause you won't put back all these 23 years old parts again Talking from experience! It always starts as a small job.

[Timm]

Fortunately you can replace the PCV and sort the manifold leaks without removing the manifold:

http://www.meeknet.co.uk/e31/BMW_E31...d_Leak_Fix.htm

As clarkitec says, start with the PCV valve at the back of the manifold and pay attention to the advice on getting a Torx bit that fits perfectly!

[clarkitect]

Is there any way you can provide me with links to the CCV and the OSV? I'm quite a noob when it comes to stuff like that. Thanks!

The CCV, or PCV at the back of the intake is this item, called a manifold cover on FCPEuro:
https://www.fcpeuro.com/products/bmw...ro-11617501562

What I called an OSV (Oil Separator Valve) is being called a Crankcase Vent Valve on FCPEuro.com. This is the one behind the timing chain. It looks like it's a different style than the M62TU version, and it appears that it does not have that little hose that breaks down. That is a good thing because I think it reduced the likelihood that you need to replace it, it may just need a flush.
https://www.fcpeuro.com/products/bmw...or-11151747066

Hopefully you are somewhat handy, or can at least follow youtube videos and Timm's instructional website. Excellent resource!

[diefncy]

Yup, I'm quite handy for an 18 year-old. I've had a Karmann Ghia, and replaced the engine in my Fathers Hilux. Just not too familiar with BMW's. Thank you for supplying the links! I'll be sure to get them

[clarkitect]

Yup, I'm quite handy for an 18 year-old. I've had a Karmann Ghia, and replaced the engine in my Fathers Hilux. Just not too familiar with BMW's. Thank you for supplying the links! I'll be sure to get them

Hah! I was pretty handy as a teenager working on my Corvair back in the day. Good luck with the project kid, I think you'll lick it and then you can take it back to that mechanic and tell him he was wrong. Those M60 engines are the more rugged than the M62 variants that followed them up. Damn thing should run forever.

[Calli74]

Subscribing to this thread. Have you done the flush? Any changes? I just had my valley pan done and all of my intake gaskets as well. My car started smoking shortly thereafter. I then replaced the PCV valve and it still blows a large puff of smoke at startup. Then while driving if I hit the throttle, I get a plume of smoke here and there. I'm wondering if somehow my OSV got clogged???? I don't know. Car runs and idles smoothly...just smokes.... I really want to get to the bottom of this.Thank you

[DorinDav]

What brand CCV plate did you use?

Cheers

Subscribing to this thread. Have you done the flush? Any changes? I just had my valley pan done and all of my intake gaskets as well. My car started smoking shortly thereafter. I then replaced the PCV valve and it still blows a large puff of smoke at startup. Then while driving if I hit the throttle, I get a plume of smoke here and there. I'm wondering if somehow my OSV got clogged???? I don't know. Car runs and idles smoothly...just smokes.... I really want to get to the bottom of this.Thank you

[Calli74]

I used a Vaico brand...purchased from ECS Tuning. After my car is warmed up - it sounds like a horn on the PCV...I put pressure on it and the sound goes away.

Thoughts?

[georgebest]

I used a Vaico brand...purchased from ECS Tuning. After my car is warmed up - it sounds like a horn on the PCV...I put pressure on it and the sound goes away.

Thoughts?

Have you reconnected the oil pipe at the bottom of the PCV/CCV? The one with the spring.

[Calli74]

Have you reconnected the oil pipe at the bottom of the PCV/CCV? The one with the spring.

Yes. At first I didn’t. Then I did. It’s all good now.

I’m picking up an OEM part on Monday night. Going to try that.



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[westaussie323i]

A little off topic but I was about to buy an E60 545i that started smoking the morning I test drove it, so I told the dealer that it was likely to be CCV or Stem seals and he didn't want to hear that and offered a direct swap for my X3, but strangely a week later it was only the CCV according to him but I suspect a tin of seal softener was more like it....my last E38 leaked oil like an old Harley but turned out the CCV was the culprit and those guys made a good deal of money buying these supposedly knackered cars and for $200 and a clean flipped them on. My point being I now make sure a second or third opinion is always good and the wealth of knowledge here is priceless plus it involves true passion for the product!

[DorinDav]

I used a Vaico brand...purchased from ECS Tuning. After my car is warmed up - it sounds like a horn on the PCV...I put pressure on it and the sound goes away.

Thoughts?

I changed mine last weekend on a whim...using a local Chinese part

It started howling and smoking within a day...burning plenty of oil
I'm going to take it apart today and see what's going on

I noticed when I sit at idle for a few minutes, the motor send a plume of burnt oil out the exhaust which tells me the plate isn't doing it's job and oil is pooling in the tube

[951Dreams]

I changed mine last weekend on a whim...using a local Chinese part

It started howling and smoking within a day...burning plenty of oil
I'm going to take it apart today and see what's going on

I noticed when I sit at idle for a few minutes, the motor send a plume of burnt oil out the exhaust which tells me the plate isn't doing it's job and oil is pooling in the tube

From all I've read, I'd check my OSV first. If it's clogged I've seen accounts that your car will keep eating CCVs.

Has anyone been able to test the OSV with the intake off by just blowing in the tube? Or is there a way to hook something to that tube if you pull the CCV without pulling the intake to test it??

My plan was just to test it that way once I took the intake off. No idea if it works tho.

And while I have the smoking issue everyone is reporting, I also have a super bad cold stall, miss, and ruff idle issue. The colder it is out the worse it is. Once it's stopped for the day it doesn't come back till it sits for 8 or so hours. Screams vacuum leak, so every top side gasket is getting replaced. I could just do a smoke test, but at the age these are getting I don't want to be playing wack a mole. So I'm just doing them all at once. I'm still kicking around if I'm going to do the valley pan while I'm in there, I've got all the other parts already but I got sick and it got cold. And hasn't stopped raining for weeks.

Unfortunately since I'm throwing parts at it, I won't be able to pin point what fixed my problems. Unless it doesn't. I will report back either way, to add to forum knowledge.

[Calli74]

From all I've read, I'd check my OSV first. If it's clogged I've seen accounts that your car will keep eating CCVs.

Has anyone been able to test the OSV with the intake off by just blowing in the tube? Or is there a way to hook something to that tube if you pull the CCV without pulling the intake to test it??

My plan was just to test it that way once I took the intake off. No idea if it works tho.

And while I have the smoking issue everyone is reporting, I also have a super bad cold stall, miss, and ruff idle issue. The colder it is out the worse it is. Once it's stopped for the day it doesn't come back till it sits for 8 or so hours. Screams vacuum leak, so every top side gasket is getting replaced. I could just do a smoke test, but at the age these are getting I don't want to be playing wack a mole. So I'm just doing them all at once. I'm still kicking around if I'm going to do the valley pan while I'm in there, I've got all the other parts already but I got sick and it got cold. And hasn't stopped raining for weeks.

Unfortunately since I'm throwing parts at it, I won't be able to pin point what fixed my problems. Unless it doesn't. I will report back either way, to add to forum knowledge.

I read something about unclogging the OSV from the bottom (dropping oil pan) can’t recall if it was on this thread or not. Try to unclog with weed trimmer line and the a Kerosene flush. Not sure how well that works. I’m up for trying it.

My valley pan and all intake gaskets are brand new. Wasn’t having the smoke issue prior to that last job I mentioned. Wondering if some debris got in the OSV line/tube?

My idle is smooth and the car runs perfect. She is just a smoky little bastard!


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[951Dreams]

I've heard tales on here (yeah, I read a lot) that the cheaper CCVs can sometimes fail. That some people have had to use several to find a good one. I know a few of the part houses are good at dropping products that cause problems however. ECS should be one of them, unless it's a new vendor for them. Someone always has to be the Ginnie pig.

I'd guess getting gunk in the line, and it getting sucked into the OSV is possible. If it was already gunked up then that might be the last straw and all. But for my money is on something not sealing or connecting right after the job. Next would be a bad CCV.

There isn't much else just doing the intake should effect oil wise. No oil channels there.

Did you have vacuum/idle problems before the work? I could see how correct vacuum vs leaking vacuum could cause a problem with a seal somewhere else. Sucking in oil now where it couldn't before. But I don't know these well enough yet to tell you where that could be.

I think your on the right track, but I'm still reading through years of post. Maybe someone with more experience with these cars has more ideas.

Edit: it seems that unlike most modern vehicles, dropping the oil pan on these is pretty easy. Flushing the OSV would be a pretty simple afternoon project, so there is no harm in trying it. I'd wait till my next oil change personally, but I'm cheap when it comes to 8 quarts of expensive oil... Lol

[Calli74]

What stinks is oil is brand new. Less than 50 miles. I may try to save in a clean container and reuse.

I had a very mild sporadic idle on cold starts prior to work. All new gaskets and it was gone. But then - the smoke.

That being said - I don’t drive it much at all right now. Took it out for a 5 mile cruise and it was like a 007 smoke screen at WOT for a few seconds.




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[Timm]

The Oil Separator Valve is one of the first things to suffer when oil-changes are missed for a few years - the grotty lacquer that builds up blocks the drain tube (and can usually be seen all around the camshafts if you remove the oil cap). It's a tiddler of a pipe - and unless the OSV is damaged by cracking it when removing the manifold, clearing the pipe with weed-whacker line will usually get it going again.

[951Dreams]

What stinks is oil is brand new. Less than 50 miles. I may try to save in a clean container and reuse.

I had a very mild sporadic idle on cold starts prior to work. All new gaskets and it was gone. But then - the smoke.

That being said - I don’t drive it much at all right now. Took it out for a 5 mile cruise and it was like a 007 smoke screen at WOT for a few seconds.




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The more I think about it, personally I think something didn't go right with the CCV. I guess the OSV could suddenly become clogged, but I'd think if your old one wasn't working right you'd have had smoke then. Since it all started when you replaced the CCV, I just have to suspect something's up with it.

But I've been wrong a time or two.

[Thuppu]

This was when I had the CCV oil separator clogged: https://www.youtube.com/watch?v=dAYS-jAfjhk

[Calli74]

This was when I had the CCV oil separator clogged: https://www.youtube.com/watch?v=dAYS-jAfjhk

Ok. That’s almost identical to what mine is going. Did you do Timm’s kerosene enema to clear the separator? (OSV) or did you replace the CCV?




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[georgebest]

Ok. That’s almost identical to what mine is going. Did you do Timm’s kerosene enema to clear the separator? (OSV) or did you replace the CCV?

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Mine was the same until I replaced CCV.