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Discussion Starter · #1 ·
Hi,
I have a 3 Series GT (F34) 318D, N47 engine, with a few symptoms that look to me like excessive crank pressure and wanted advice before I start replacing parts.

Car has 168K miles on it and the engine was reconditioned about 28K miles ago. Just before the recon, it had the cam cover, which includes the integrated oil separator and valve etc. built in replaced by BMW. The recon engine had this component installed from my original engine.

At first I have found that I had an oil leak underneith and cleaning up, running for a few days and then inspecting, appears to be coming from within the bell housing. Even the inside of the starter motor (the bit that goes into the bell housing) is oily and it has that kind of oil mist look about it, where it has gone everywhere and drifted down the underside of the car. This is odd as the rear crank seal was done as part of the recent reconditioning.

While under the car I noticed that the pipe from the turbo to the charge air cooler (Intercooler) and the pipe from this to the throttle body appear to be blowing oil at the joining interfaces. I cleaned these up and after a short drive, some oil was back, so I took the inlet pipe off and took a look at the turbo. The turbo spins freely by hand and there are not really any scuff marks on the housing, but with some force from my thumb, I am able to move the impeller up and down or sideways so that it can touch the housing, but it does take some pushing to do this.
Tire Automotive tire Tread Wheel Alloy wheel

I also removed the oil breather pump from the separator to the inlet pipe and this is clear and in good condition. I also removed the cap over the oil breather valve diaphragm and the diaphragm and spring is in good condition and the small hole to ambient air in the cap is not blocked and it is not coked up etc. in there.

I am thinking these are probably related and was thinking that maybe replacing the turbo would fix everything, but talking to a turbo rebuilder he has suggested that a turbo should last beyond the life of the engine if all is working fine and so if my turbo has worn, then something is not right, such as the oil separation system, but that was relatively recently canged.

I am thinking that as high pressure oil appears to be blowing by the new crank oil seal, then I must have higher than usual crank case pressure and this might be putting the crank breather system into by pass mode (bypassing the cyclones), resulting in higher quantities of unseparated oil going into the inlet causing the oil leaks I have found at the front end, but I cannot figure out what mechanism could be causing high crank case pressure, if that is my issue.

I am a competent home mechanic and am thinking I would change the turbo and may drop the gearbox to change the rear crank seal, but am thinking I may also need to change the cam cover again.

I would greatly appreciate any thoughts on this? as I am getting really stuck as to what to do next and we really love the car.
 

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One things for sure is that turbo is kaput,there should not be that amount of movement. If you can move by hand when it’s working it will be touching the housing. I would bet if compressor housing was removed there will be marks inside on fins and housing.

before suspecting high crankcase pressure is it possible the rear main has just failed or been damaged when fitting? Also having some oil inside the boost pipework is quite normal it just depends how much is in there?
 

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Discussion Starter · #3 ·
Thanks for the responce. I am planning to replace the turbo and I am sure as the bearings have started to go on it, allowing more lateral movement, it is probably leaking more oil into the inlet, I am just concerned about what may have caused the turbo to fail? and so will a new one also fail if I have not addressed the issue.

Anyone have any experience with the life of these turbo's? do they eventually wera out under high mileage, or is there other reasons that are likely to cause this on the N47 engine?
 

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So long as the oil pipes are ok I would say it’s just one of them things. I did an x3 timing chain amongst other things a few months back and found turbo to be exactly the same as that checked oil pipes and they were fine so just threw a CHRA at it and it’s been fine since
 

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Discussion Starter · #5 ·
Thanks.

Does anyone think I should replace the cam cover that contains the oil sepatation cyclones, over pressure bypass valve and breather valve etc. at the same time, just to be sure?

If so does anyone have any experience with doing so and which bits are tricky? It looks like the injectors need to come out and the fuel rail, but other than that looks relatively easy. Is this correct, the job is quite straight forward?

When removing the injectors and then replacing them, do I need to change any seals etc or should I just be able to put them back in a tighten (making sure the same injecotr goes back into the same position)?
 

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It’s not too bad to do like you say injectors and fuel rail off and a bit of wiring. And yes definitely change the copper washers on injectors when refitting and torque bolts to spec.

suppose for peace of mind you could change the cover because if it is at fault you could blow another rear main. Is there any way to test the breather system on the latest version? On older stuff you could but not sure about the cyclone types.

will you be doing the job yourself or will you be getting a
 

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Discussion Starter · #7 ·
Thanks. I will be doing it myself for peace of mind and to save cost.
My next dilema is whether to go with a genuine BMW cam cover, or go with say FEBI or other known part manufacturer. Looks like I can get a genuine for around £300 (although dont know if this includes the seals) and a FEBI for £135 (including the seals). If anyone has used aftermarket cam covers and had good or bad experience, I would appreciate the feedback?
Anything else I should change while I am there?
 
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