(M70) Lot of smoke on passenger exhaust side

[Marc850]

Hello everyone,

Ok so I dropped my car at my BMW Specialist. The problem is that I have a lot of exhaust fumes on one exhaust side:

- The colour is grey: not dark sooty
- The smell is more like an engine running too rich: really atrocious smell especially when cold, I'm a bit ashamed in traffic jam when it looks like my car is having a hookah
- The fumes are very important when idling especially on a cold engine
- It also happens when accelerating on a cold engine
- When the engine is hot I think it's only when idling
- I did a CO2 test myself and it came back negative
- My mechanic informed me that my coolant was pressurised but I do have a leak on the central pipe between the V

My specialist says he can't figure out what's coming out of that exhaust.
He suggested connecting the car to his diagnosis tool and see what's what. If nothing is there, he will take compression levels. He was also thinking about using a machine that mesures the types of gaz that are contained in the fumes: what should we expect ?

Is there anything I should have him look for first ?



I'm a bit sad to spend so much money and never get to enjoy the thing and I'm very thankful for anything you can do to help me enjoy my 6 Speed beauty

[PabloRock]

Are you sure you are running on all 12? I lost a bank (it was a bad MAF) and that's what I got (more white than gray), but lots of smoke.

[Marc850]

I think I am. Having experienced that in the past I'm definitely not driving on only 6 cylinders (LHM).
I did try switching each other MAFs but the smoke was still coming from the same side.

[rjjablo]

Check Plugs, Plug Wires, Distributor Caps, Rotors, Intake boots, Intake manifold gaskets when cold

[Marc850]

Plugs have been changed in September of last year. One of them had some oil on it but it was precisely on the side where the valve cover gasket is leaking so I didn't worry to much about it...

I'll have him check the rest but I am running out of money. I have got a quote for the intake manifold gaskets since we will be removing the intake in order to fix the leak between the V and they are 109,64 excl VAT and they are four of the damn things...

[rjjablo]

Plugs have been changed in September of last year. One of them had some oil on it but it was precisely on the side where the valve cover gasket is leaking so I didn't worry to much about it...

I'll have him check the rest but I am running out of money. I have got a quote for the intake manifold gaskets since we will be removing the intake in order to fix the leak between the V and they are 109,64 excl VAT and they are four of the damn things...

Max Lumens makes a thin silicone Gasket kit that helps seal or you use an 1/8" bead of Reinzoil. Do a search for it. You still pay for the Labor either way.

I used the Max Lumens and it worked until it got cold in the fall, I am getting ready to do the Reinzoil as soon as I put my dash back in after replacing the heater core. These cars are not for the faint of heart

[PabloRock]

As rjjablo says, just a use a sealant for the intake gaskets. I did it to mine and it made a world of difference (used a Toyota product instead of the Reinzoil). I think I was actually a little light on it, so may do it again, but made a big difference. And the best part is that it's only $10 (not counting the valve cover gaskets). The only thing is that it is a lot of work to get to them. Not real difficult, just a lot to take apart and move aside. (but on the plus side, gives you a chance to clean up all those spaces you normally can't reach and paint your valve covers).

[Marc850]

Some news on this:
- Compressions are good (between 7 and 8) (even slightly better on the passenger side)
- No default is display with diagnostic tool
- Gaz analysis displayed no significant difference and emission levels are OK (even slightly better on the passenger side)
- The same plug is still oily: it's the one on cylinder 6 (Back of the motor on passenger side)

Here's some pictures of the same plug when I've changed it back in september:
IMG_1128.jpgIMG_4752.jpgIMG_8583.jpg

My mechanic says:
- He really don't think that it comes from something electrical because the car runs smooth and the fumes are OK
- This could be from a piston ring to which could still give compression but let the oil inside the chamber
- This could be from valve guides
- This could be from the valve stem seals which I thought you could replace without removing the cylinder head, but he say's that you have to

Do you guys have any idea ? I really appreciate any help


What I'm going to do for now:
- Fix the coolant leak
- Fix the oil leak at the passenger valve cover gasket
Which should bring me to around 2000euros

I will drive the car around afterwards and measure exactly oil consumption. If it is in fact the engine and that it needs a complete rebuild, I might consider it in the more distant future as my mechanic says it should be more than 10000 Euros

[rjjablo]

Check that Plug wire for the Oily plug for continuity with a multimeter, cheap and easy.

Safety wire or Loctite the Banjo Bolts on the Oil Bar with he is in doing the Valve Cover Gaskets and intake manifold

You can do the Valve Stem Seals with the Heads on. Requires a special tool. You hold the valves up with either rope or compressed air.

[Marc850]

I have the opportunity to buy an engine with less than 60k miles with a 6 months warranty for 1.5K euros. I don’t know if I should do it or stick with the original

[Timm]

That is certainly oil and not soot from poor combustion - my best guess is valve stem seals. That is not that expensive to repair, just rather long-winded

[Marc850]

I will try to get my mechanic to do the valve stem seals and check the plug wire on that plug. Hope it’s as simple as that, fingers are crossed

[Marc850]

I suggested the method without taking the cylinder heads out: he says he wont do it because it might make financial sense if an enthusiast does it but it does not save that much time for a professional and the risks are higher. According to him it might end up costing me more than taking the heads off if one of the valves falls down, and also if the valve guides are kaput, it wont solve it.

So, once again I am completely lost.

Should I:
1) Just swap the engine with that 55000 mile one: This one is tempting
- Plus side: It's 6 months warrantied and low mileage. I have a collection of spares with the old engine.
- Downside: The car's value will probably go down without it's original engine and this engine might end up being as bad or even worse than the first one. Still expensive... How many work hours do you think it can take ?
2) Take my car back and try doing the valve stem seals and fix the oil an water leak myself
- Plus side: Less expensive
- Downside: I have to buy the special tools and have to take quite a bit of time to do it.
3) Just have my mechanic do the oil and water leak and drive with stinky smoky 850

[cartoonz]

Option 4. - GET A NEW BMW TECH.
This guy is in over his head.

[Marc850]

Well busy day today, I got the car back which drove beautifully: after a 30 minute drive I didn't get smoke from the exhaust once I got home. I got the compression numbers: between 7 and 8 on all cylinders. I also have the exhaust fumes analysis values on both exhaust which I can post if you're interested.
IMG_6298.jpg

I've then started unbolting thing: pretty straight forward until I got to the intake itself. Pretty hard to get access to the lower bolts, and feel like putting it back on will be even harder. I've noticed that my intake boots are not in good condition at all, especially on the driver side. Both PCV Valves were very poor as well: they were inserted in the valve cover and sealant seemed to have been used which I dont think is advisable ? I don't think it was linked to the PCV Valves tho because I did have some negative pressure on the oil filler with the engine running. I will change them anyway. Air pipes on throttle body are also trashed.
It was getting dark so I didn't have time to get to the valve covers.

IMG_5008.jpg
Here's a picture of the intake port on cylinder 6 (the one with the oil flooded spark plug). Some of them are greasy, some of them are not: I don't know what that means. Well none of the valves are broken which is quite nice.

Do you guys know how to get the intake back to it's factory fresh look ? I was thinking sand blasting and maybe a clear coat on top ?

[Timm]

Great work - no prevaricating and straight into it! Leaky valve stem seals will be seen as darkened valve stems and black at the top of the valve

[PabloRock]

Those intake gaskets look good, so just a sealing will help quite a bit (was thrilled when I saw mine because of $$$$). A wobble drive and a couple extensions help with those pain in the butt bolts and a magnetic socket and some grease to keep the nut on. My biggest pain was cleaning the intake manifolds. If I knew my friend had a blasting cabinet, I could have saved a day. (There should be a rule that when you have a "mechanical" friend, they give you a list of all the tools and skills they posses). Now that I know he also does upholstery, I have some work for him for my Saab.

[Marc850]

I got to do a bit more today.

I first took out the valve cover to discover one good looking engine (110K Miles approximately) and tight Banjo Bolts
IMG_6317.jpgIMG_6318.jpg
I then tried to take out the intake gaskets, but of course my 12mm was nowhere to be find. I had another one but could only take out the short ones.
IMG_6319.jpgIMG_6323.jpg
They look quite cracked to me, will Reinzosil will do the trick or do I have to sell a kidney ?

I also took out the spark plugs wires and measured resistance:
Coil1: 2.0 KOhm
1: 5,68 KOhm
2: 4,78 KOhm
3: 5,60 KOhm
4: 5,99 KOhm
5: 6,06 KOhm
6: 5,69 KOhm (the one with the oily spark plug)
Coil2: 1,86 KOhm
7: 5,64 KOhm
8: 6,08 KOhm
9: 5,86 KOhm
10: 6,03 KOhm
11: 6,07 KOhm
12: 6,06 KOhm
Side 1-6 (also known as smoky exhaust side) were BREMI wires, the other side was OEM BMW.

I had a look at the caps and rotors and will be replacing them:
IMG_6328.jpg

But my biggest problem, by far, is that stupid rear coolant crossover pipe. I've managed to get the 3 passenger side bolts out and the top driver bolt out. But my problem is the lack of space on the driver side. I can't take out the 2 remaining bolts and replace the central tube o rings and rear crossover pipe seals.
Has anyone ever done it ?

[Marc850]

Well all valve stem seals are changed (and it looked like they may have already been changed before).

The engine starts and run well but it is heating up when idling, as my mechanic told me before. But I thought it was because of the coolant leak.
Isn't the M70 self bleeding ? So on a cold engine: Coolant cap off, heater temp on max, blower on max, refill the coolant tank as long as it's needed. Put the cap back on and there you go right ?
Anyway It seems like my engine is toast. Well at least it looks beautiful now
moteur.jpg
It also seems to be smoking still from the same exhaust side

[Timm]

Here's how to bleed the system - but don't write the engine off without a block test!

[Marc850]

Great video, you got one more subscriber

I would really like to avoid getting rid of the engine because sourcing a good used one seems like a hard task. I just saw the engine of my previous (rear) fire damaged 850i which had 220000 km advertised on a website with "90000km" for 1790€ so...

I took it for a test drive earlier on and it did not overheat. Once I came back there wasn't any smoke from the exhausts. So I guess we'll see

[Timm]

If it overheats at idle the most likely failure is the viscous fan:

[Marc850]

The engine is not overheating anymore, so that's good.
I've done about 100km with the car since the repair. I took it back from work and made use of the mandated seclusion to check the 6th spark plug as I had noticed that this morning the idle was a bit hesitant.

And sure enough, here is spark plug number 6 VS Number 3:
numero 6.jpgnumero 7.jpg
Number 6 was of course replace after doing the valve stem seals job.

What should I investigate next ?

[rjjablo]

Stuck Oil Control Ring. Compression Check and Leakdown Test, Seafoam Treatment