[ms84]

Hello all,

You are my last resort guys...

I'm having a nightmare with oil loss affecting EGR cooler. I have F34 318d with N47 engine 103k miles on the clock. Since three years it drinks on avarage 1 litre of oil per 2000 miles. In theory not a disaster but it gets my EGR cooler sooted. Let me start from the begging. In 2021 an EGR cooler recall was done. Within 8 months I had an engine light on with code 290900 air mass too high. Was trying to find out what the issue was but BMW recalled the EGR cooler for the 2nd time so I went for it (2022). Imagine my surprise when after collecting my car the code 290900 was gone. Happy days, thought all problems gone. Unfortunately, another 8-10 months and the error code 290900 was back together with the engine light. That was the time when I learnt how to test the level of EGR cooler sooting using ISTA. Done it and got results that the exhaust flow value through the EGR cooler is under 80% meaning severe sooting. Ok, what to do. Complained to BMW dealer and after a bit of a hassle they have replaced it again. My car was there 3 times for investigation within a span of 3 months and as they couldn't find the issue connected with 290900 code they decided to replace the EGR cooler. On top they replaced some valve connected to the cooler and topped the oil up half a litre. Of course the code cleared itself. Another 8 months and again, the cooler is sooted. In this place just want to inform you that there is no coolant leak. Always the same level. Beginning of April this year I put my car to independent BMW specialist and they diagnosed faulty turbocharger. Apparently oil was all over my intake system. Got a new one installed, manifold, EGR cooler and DPF cleaned (Dpf was clean anyway but done it just in case) etc. And again, after driving 1500 miles half a litre of oil escaped and the sooting of EGR cooler dropped from 100% to 90% so at a faster rate then when installing a brand new cooler.

What's been done to resolve this:
- 3 EGR coolers replaced
- new turbo
- new timing chain (at 75k miles)
- walnut blast (March 2023)
- new charge pipe seal (throttle side) as I had some oil marks over there (March 2024)
- smoke test done once a year
- car checked 5 times by the dealer, 2 times by the BMW specialist within the last 3 years
- computer diagnostics etc

I have replaced an alternator pulley over the last weekend and to get there had to remove throttle body. Could see traces of oil inside in spite of it was fully cleaned begging of April while doing turbocharger.

I have ISTA and during the past three years I had not a single error code connected with engine, intake or exhaust apart from that 290900 coming back when the EGR cooler is sooted. There is no smoke from the rear or anything suspicious.

I'm thinking now to replace the PCV valve but I'm sure that's not the issue as it has been checked twice by two different BMW specialist.

What next in my case? Head cover replacement? Valve seals? Piston rings? The worst thing is there is no other signs, fault codes so I'm not even sure where to look...

The car is going back to the dealer but they have no clue either...

[TurboWeasel]

Originally Posted by ms84

I'm thinking now to replace the PCV valve but I'm sure that's not the issue as it has been checked twice by two different BMW specialist.

The "Air mass too high" fault code is kind of a clue to that, along with the excessive oil consumption. The rubber diaphragm on top of the cam cover might have been checked, but the oil separator galleries inside it could have cracked, causing an air leak. This is why BMW replace the lot under warranty with any kind of PCV or cam cover gasket leak issue.

There is also a PVC breather pipe attached to the turbo which is known to harden and split in half over time.

I would try getting that lot diagnosed firs before delving into the bowels of the engine.

[ms84]

I'm gonna get new PCV valve today and will see but not having big hopes. Breather pipe replaced 2 years ago. Will get it checked anyway. The code 'air mass too hight' shows up only when the EGR cooler is sooted and the exhaust flow thru the cooler drops to under 80% against what is calculated by the computer.

[Allworth]

You can check compression of each cylinder to eliminate worn piston rings. At 100k miles there should be no issues with piston rings on well maintained cars.

[ms84]

Originally Posted by Allworth

You can check compression of each cylinder to eliminate worn piston rings. At 100k miles there should be no issues with piston rings on well maintained cars.

That's a good idea to eliminate one possible cause. I'm not following BMW's recommendations to oil change intervals just in case plus I'm quite sensible when it comes to my cars so every single squeak, noise, issue is sorted straight away hence I'm so frustrated when it comes to that cooler and oil as nobody can correctly diagnose it.

[ms84]

New PCV valve on. Not sure how the old one should look like but the rubber was definitely stiff and even that old spring didn't want to come off. I did read somewhere a person asked a question if you should feel the air coming out that little pin hole on top of the PCV valve so I did check with a finger and couldn't feel anything from the old one but the new one definitely 'shooting' with air while engine is on. Hope that's a good sign?

[TurboWeasel]

Shooting? Do you mean a hissing noise? Hissing indicates an air leak usually.

[mrbensam]

I feel your pain I’ve just had engine light come on with EGR codes because of oil consumption on my 30D 🥲

[ms84]

Originally Posted by TurboWeasel

Shooting? Do you mean a hissing noise? Hissing indicates an air leak usually.

No, there is no noise of any sort but I can feel on my finger some air coming out that little pin hole on the top of the valve when engine is on. Didn't feel it with the old valve.

[ms84]

Originally Posted by mrbensam

I feel your pain I’ve just had engine light come on with EGR codes because of oil consumption on my 30D 🥲

By any chance, do you have 290900 code?

[mrbensam]

Originally Posted by ms84

By any chance, do you have 290900 code?

Yes mate that’s the code I had a couple days ago, I’ve just cleared it for now to see how long it takes to come back

[ms84]

Originally Posted by mrbensam

Yes mate that’s the code I had a couple days ago, I’ve just cleared it for now to see how long it takes to come back

It will come back quick, don't worry

Do you have ISTA? Run an Air mass test and it will measure exhaust flow value through the EGR cooler. If you have oil loss and that code I suspect your cooler will be sooted. Should look like that:



Hopefully that's not your case otherwise a nightmare to sort it out.

[mrbensam]

Originally Posted by ms84

It will come back quick, don't worry

Do you have ISTA? Run an Air mass test and it will measure exhaust flow value through the EGR cooler. If you have oil loss and that code I suspect your cooler will be sooted. Should look like that:



Hopefully that's not your case otherwise a nightmare to sort it out.

I have got ISTA mate I’ll give it a go, I will probably just delete EGR and DPF if it’s failed

[mrbensam]

Originally Posted by ms84

It will come back quick, don't worry

Do you have ISTA? Run an Air mass test and it will measure exhaust flow value through the EGR cooler. If you have oil loss and that code I suspect your cooler will be sooted. Should look like that:



Hopefully that's not your case otherwise a nightmare to sort it out.

Funny enough engine light has just come back on! Only been 2 days Same code 290900

[ms84]

Originally Posted by mrbensam

I have got ISTA mate I’ll give it a go, I will probably just delete EGR and DPF if it’s failed

Ahh, thought I'd have company while looking for the solution

[mrbensam]

Originally Posted by ms84

Ahh, thought I'd have company while looking for the solution

My cars used 15 litres of oil since January mate hahaha, been to like 5 different garages and every single diagnosis has been wrong 🥲

[ms84]

Originally Posted by mrbensam

My cars used 15 litres of oil since January mate hahaha, been to like 5 different garages and every single diagnosis has been wrong 🥲

That's well more than mine lol hope it's not in front of me yeah, it's wired as mine is using constant 1 litre per 2/2.5k miles since 3 years. If you would think there is an internal leak, with time this leak should be bigger in theory. Was thinking about blanking the EGR but 1st it's illegal so don't want to have any troubles because of that and 2nd at some point will have to sell this car so it need sorting anyway.

[StuieUK]

to note:
i blanked the EGR in my 335d, and i pass emisions test within the legal limit.
I burn 1ltr oil every 2.5/3k miles, and have Zero leak of any kind (i parked up on paper in my garage for 2 weeks a while back, apart from a dead spider and tire tracks reversing off, not 1 spec of oil on the paper.....)

[mrbensam]

Originally Posted by StuieUK

to note:
i blanked the EGR in my 335d, and i pass emisions test within the legal limit.
I burn 1ltr oil every 2.5/3k miles, and have Zero leak of any kind (i parked up on paper in my garage for 2 weeks a while back, apart from a dead spider and tire tracks reversing off, not 1 spec of oil on the paper.....)

Did you delete the DPF as well? Tuner said if you blank EGR it will clog up the DPF

[StuieUK]

no, i didnt know about the DPF setup, i just said blank off the EGR..
however, have read plenty of stories of those who had the EGR blanked and software coded out, and no issue has come of the DPF

[TurboWeasel]

As long as the EGR function is coded out properly, the ECU won't look for the interruption in air mass and perform the DPF functions as normal.

If you just blank it off and do nothing else, you won't get any regens and the DPF will indeed clog up.

If your engines are burning that much oil, it's either the turbo(s) or the engine - worn piston rings, valve guides, scored cylinder bores....that kind of thing. If it was blowing past crank seals or down the PCV outlet, there would evidence of it.

The only way to be sure is to pull the injectors and check the nozzles for oily deposits. They should all be dry. Stick a bore scope small enough down there to check for cylinder/piston damage and do a compression/leak down test whilst you're there.

[mrbensam]

Well I’m booked into a specialist tomorrow for the EGR fault.. I will let you know what they say after they pull my pants down