[bimmerquick43321]

Hello, after getting my car repaired, the garage mentioned I have an oil leak on the front crank seal. Two questions

1. Stupid one but still, are there 2 crank seals?I mean a front and a back seal? Guessing the sensor is on the front in any case right?

2. How complicated is it to do, garage mentioned 2h to 2 1/2h, noticed that's for an XI as intake manifold needs to be removed, apparently it can be accessed simply from under the car? Is that true, the guy who did my estimate, might of just not know or be sure and didn't want to take the chance, they usually give me worst case scenario for the time it would take them...

So if it's a simple question of accessing the sensor from under the car, as it's not broken not going to change it for nothing, however if does take 2h+ to replace the seal, probably a good idea to do the sensor as well no?

[bimmerquick43321]

Originally Posted by Broken_Gearbox

1. Yes. Front and rear.

Thanks, but only 1 sensor in front right?

[kkasson]

There is a rear main seal on the back of the engine and a front main seal on the front. The crankshaft position sensor is near the back of the engine, but it is outside of the seal. The sensor can be replaced without touching either seal. On the AWD models the sensor is accessed from the top by removing thr intake manifold, on RWD it's easily accessible from underneath. But the crank seals are completely separate in either case.

[hassmaschine]

The sensor is in the block. There's no sensor on the front of the crank.

[bimmerquick43321]

super thanks for the info guys

[matteblue3er]

Originally Posted by mecbain

Hello, after getting my car repaired, the garage mentioned I have an oil leak on the front crank seal. Two questions

1. Stupid one but still, are there 2 crank seals?I mean a front and a back seal? Guessing the sensor is on the front in any case right?

2. How complicated is it to do, garage mentioned 2h to 2 1/2h, noticed that's for an XI as intake manifold needs to be removed, apparently it can be accessed simply from under the car? Is that true, the guy who did my estimate, might of just not know or be sure and didn't want to take the chance, they usually give me worst case scenario for the time it would take them...

So if it's a simple question of accessing the sensor from under the car, as it's not broken not going to change it for nothing, however if does take 2h+ to replace the seal, probably a good idea to do the sensor as well no?

You need to clarify a few things here. Is it the crankshaft SENSOR or the front and/or rear crankshaft seals that are being replaced? Given your labor quote and your question about manifold removal, you are probably referring to crankshaft SENSOR seal replacement, NOT crankshaft SEAL replacement. Rear main seal will require transmission removal and will take much longer and 2.5 hours.

As mentioned, there is only 1 crankshaft SENSOR and it is not near or directly related to crankshaft SEALS nor replacement of crankshaft seals. You do not need to replace CRANKSHAFT SEALS along with the crankshaft SENSOR SEAL.

The crankshaft SENSOR AND ITS SEAL (not shaft seal), can be replaced WITHOUT intake manifold removal. I've done it numerous times. You only need to remove the airbox and some ducting depending on N5x variant. Drivetrain configuration does not matter, I've done it on both xi and RWD models.

To be fair, official tech documents suggest intake manifold removal.

[bimmerquick43321]

I'll have to ask to confirm, but on my last bill it says "front crank seal oil leak", so not related to sensor from your explanation