Last effort

[Jonny3777]

Hey guys,

As the title suggests I'm out of options on how to fix my 2006 2.0 z4. Theres 140k miles on her.

She's been puffing white smoke intermittently for the past year with a juddering idle every now and then. Had her checked by 3 different mechanics no answers. I fear oil is being burned in the engine

My radiator fan isn't working not and my engine gets up to temperature after 5 miles or so of driving???

Oil consumption seems high, I have to top up 1 liter every 1000km.

Things I've tried so far.

O2 sensor bank 1 fault check engine light, changed O2 sensor fault still there.

Serviced twice a year.

CCV valve was checked no signs of degradation. (may get it changed anyway as a last resort)

One mechanic mentioned my rings may be worn I instantly linked this to my radiator fan not working!

That's the worst case scenario. Value stem seals are also a possible culprit but idk?

I'm at the end of my rope I've put a lot of money into service inspections with no solutions. Hoping you guys have any other ideas?

[john-e89]

Rings or head gasket I'd think. Neither has any influence on the fan though. I'd suggest a compression test of all the cylinders.

Hope you get sorted.

[Paul_RK]

Jonny3777, so, the first time you should to do is replace the fan ASAP. The problem is , that the coolant temperature on instrument cluster not show actual and real temperature of coolant, i mean that the arrow can stand vertically, but temperature could be from 90 to 105-110 degrees, it's the coding "joke". And for oil it not so good to work with high temperature range. Actual temp you can see online using OBD2 diagnostic tools. You can also coding your cluster and change the t range between the marks. Increased engine temperature affects on oil burn.
The m54 ( i think you have m54) is very stabil engine, and problems with the rings is not so often.
The idea is:
1) Check your cylinders inside with camera on damages ( i mean side walls)
2) If they are ok you can try to use special liquids to dissolve\ clean burning oil on rings and between rings, and make them work again
3) On this mileage the standart problem is oil-removing caps, if you not change them earlier - it's great time to change them ( 24 pcs, advice - purchasing only OEM , not analogue)
4) If the problem will not resolve - another advice, change the engine to m54b30 (swap) without this problems.

[tug]

This will be the N46 engine. Hope you get it sorted mate.

[buzyg]

Rings or head gasket I'd think. Neither has any influence on the fan though. I'd suggest a compression test of all the cylinders.

Hope you get sorted.

I'm with John. Hope it's viable.

[Chippie]

She's been puffing white smoke intermittently for the past year with a juddering idle every now and then.

I wouldn’t have thought head gasket if it’s intermittent, possibly breather system blocked creating back pressure, but certainly do a compression test and go from there.
Does your Zed have aircon? Does the fan come on with the aircon turned on?

[Jonny3777]

She's been puffing white smoke intermittently for the past year with a juddering idle every now and then.

I wouldn’t have thought head gasket if it’s intermittent, possibly breather system blocked creating back pressure, but certainly do a compression test and go from there.
Does your Zed have aircon? Does the fan come on with the aircon turned on?

The Aircon doesn't work unfortunately. The compression test is next on the list.

[Mr Ward]

She's been puffing white smoke intermittently for the past year

How often and how thick is the smoke when she puffs?

Does she smoke when driving normally or when you pull off from a standing start?

[Paul_RK]

tug, it' s no matter what engine, the symptoms are the same,and advises will be the same, with a little differences in details

[Mike6]

Before having the compression checked, take out the spark plugs and see what condition they are in. If they are very oily then you are almost certainly burning oil so next check that emission pipework isnt clogged . This could be increasing crankshaft pressure and forcing oil into the bore.
Dont give up, could turn out to be an easy fix.

[Mike6]

Before having the compression checked, take out the spark plugs and see what condition they are in. If they are very oily then you are almost certainly burning oil so next check that emission pipework isnt clogged . This could be increasing crankshaft pressure and forcing oil into the bore.
Dont give up, could turn out to be an easy fix.

[Jonny3777]

She's been puffing white smoke intermittently for the past year

How often and how thick is the smoke when she puffs?

Does she smoke when driving normally or when you pull off from a standing start?

Most noticeable on start up, doesn't usually smoke while driving.

I notice it more when the oil level is full.

[Jonny3777]

Before having the compression checked, take out the spark plugs and see what condition they are in. If they are very oily then you are almost certainly burning oil so next check that emission pipework isnt clogged . This could be increasing crankshaft pressure and forcing oil into the bore.
Dont give up, could turn out to be an easy fix.

Will definitely look into that Mike thanks. That never occurred to me this is a great place to get some fresh prospective

[Jonny3777]

Jonny3777, so, the first time you should to do is replace the fan ASAP. The problem is , that the coolant temperature on instrument cluster not show actual and real temperature of coolant, i mean that the arrow can stand vertically, but temperature could be from 90 to 105-110 degrees, it's the coding "joke". And for oil it not so good to work with high temperature range. Actual temp you can see online using OBD2 diagnostic tools. You can also coding your cluster and change the t range between the marks. Increased engine temperature affects on oil burn.
The m54 ( i think you have m54) is very stabil engine, and problems with the rings is not so often.
The idea is:
1) Check your cylinders inside with camera on damages ( i mean side walls)
2) If they are ok you can try to use special liquids to dissolve\ clean burning oil on rings and between rings, and make them work again
3) On this mileage the standart problem is oil-removing caps, if you not change them earlier - it's great time to change them ( 24 pcs, advice - purchasing only OEM , not analogue)
4) If the problem will not resolve - another advice, change the engine to m54b30 (swap) without this problems.

Thanks for the ideas, tbh swapping an engine out is not an option for me. Rather keep and rebuild the one I know than risk taking on additional problems.

The fan is on the list of parts to buy, just bought a new Ccv breather so that should arrive next week for install.

I'm really hoping the rings are OK as 140k miles isn't very high Mileage by any cars standard. Then again who knows.

[Mr Ward]

tbh swapping an engine out is not an option for me

I agree with you on this. I have recently fully stripped and rebuilt my Z's engine rather than replace it. At least doing it this way you know exactly what has and hasn't been done to the engine. Plus it gives you the satisfaction of knowing that you will get many more enjoyable miles from the engine.