[roxiedog13]

have a 2014 X3 sport 6CYL, only has 50,000 miles and gently driven by my wife

We are seeing oil dripping from the back underside of the engine, the mechanic (non BMW garage) is guessing it is the rear engine oil seal.

Could this be a valve cover or CPV valve leak? I cannot find any other common problem like this, hoping it's not a rear engine oil seal.

[383vett]

Often it is the valve cover or the oil pan. I changed my valve cover which solved my leak.

[6MT_Addict]

Originally Posted by roxiedog13

have a 2014 X3 sport 6CYL, only has 50,000 miles and gently driven by my wife

We are seeing oil dripping from the back underside of the engine, the mechanic (non BMW garage) is guessing it is the rear engine oil seal.

Could this be a valve cover or CPV valve leak? I cannot find any other common problem like this, hoping it's not a rear engine oil seal.

Common gasket leaks on the N55, which you absolutely will need to deal with at some point owning it:

- Valve Cover
- Oil pan
- Oil Filter Housing

The valve cover gasket usually leaks between 40-80,000 miles, depending on many things. It usually fails at the back corner (passenger side) and drips down onto the exhaust. You'll smell burning and sometimes see smoke.

Less likely is the oil pan gasket, usually lasts longer, it's a different kind of gasket.

Even more less likely for the mileage but possible is a PCV valve failure. This will create a howling noise because pressure ends up being released through the front and rear main seals with a failed valve. The valve usually won't fail until well after 60k miles though and you'll hear the howling before the seal is damaged to the point it needs replacing. This is what usually will cause a rear main seal to fail on these engines.

So in summary, check your VCG and OPG first, it's probably the VCG, mileage is right for it to fail.

Easy job, but lots comes off. Here's mine after removing the valve cover, for reference on how much gets pulled.

If you get the valve cover gasket done, ONLY use Mahle or BMW (Mahle makes them for BMW, so it's the same product regardless of which of those two you buy). Also consider replacing the valve cover. They eventually crack due to heat cycling and the PCV issue above happens maybe around 100k miles give or take, and the PCV is built into the valve cover. The JB Speed cover off Amazon, based on user reviews in N55 Facebook groups, appears to be OEM sold under a different name, and significantly less $$.

[Polo08816]

Originally Posted by 6MT_Addict

Common gasket leaks on the N55, which you absolutely will need to deal with at some point owning it:

- Valve Cover
- Oil pan
- Oil Filter Housing

The valve cover gasket usually leaks between 40-80,000 miles, depending on many things. It usually fails at the back corner (passenger side) and drips down onto the exhaust. You'll smell burning and sometimes see smoke.

Less likely is the oil pan gasket, usually lasts longer, it's a different kind of gasket.

Even more less likely for the mileage but possible is a PCV valve failure. This will create a howling noise because pressure ends up being released through the front and rear main seals with a failed valve. The valve usually won't fail until well after 60k miles though and you'll hear the howling before the seal is damaged to the point it needs replacing. This is what usually will cause a rear main seal to fail on these engines.

So in summary, check your VCG and OPG first, it's probably the VCG, mileage is right for it to fail.

Easy job, but lots comes off. Here's mine after removing the valve cover, for reference on how much gets pulled.

If you get the valve cover gasket done, ONLY use Mahle or BMW (Mahle makes them for BMW, so it's the same product regardless of which of those two you buy). Also consider replacing the valve cover. They eventually crack due to heat cycling and the PCV issue above happens maybe around 100k miles give or take, and the PCV is built into the valve cover. The JB Speed cover off Amazon, based on user reviews in N55 Facebook groups, appears to be OEM sold under a different name, and significantly less $$.

The PCV valve is part of the valve cover, correct?

[frisbeeguy]

Originally Posted by Polo08816

The PCV valve is part of the valve cover, correct?

yep

[Polo08816]

Originally Posted by 6MT_Addict

Common gasket leaks on the N55, which you absolutely will need to deal with at some point owning it:

- Valve Cover
- Oil pan
- Oil Filter Housing

The valve cover gasket usually leaks between 40-80,000 miles, depending on many things. It usually fails at the back corner (passenger side) and drips down onto the exhaust. You'll smell burning and sometimes see smoke.

Less likely is the oil pan gasket, usually lasts longer, it's a different kind of gasket.

Even more less likely for the mileage but possible is a PCV valve failure. This will create a howling noise because pressure ends up being released through the front and rear main seals with a failed valve. The valve usually won't fail until well after 60k miles though and you'll hear the howling before the seal is damaged to the point it needs replacing. This is what usually will cause a rear main seal to fail on these engines.

So in summary, check your VCG and OPG first, it's probably the VCG, mileage is right for it to fail.

Easy job, but lots comes off. Here's mine after removing the valve cover, for reference on how much gets pulled.

If you get the valve cover gasket done, ONLY use Mahle or BMW (Mahle makes them for BMW, so it's the same product regardless of which of those two you buy). Also consider replacing the valve cover. They eventually crack due to heat cycling and the PCV issue above happens maybe around 100k miles give or take, and the PCV is built into the valve cover. The JB Speed cover off Amazon, based on user reviews in N55 Facebook groups, appears to be OEM sold under a different name, and significantly less $$.

We have a howling sound on our F25 35i as well as an oil leak near the rear of the oil pan.

However, the howling sound seems to be coming from the radiator fan.

We're at 137,000 miles at this point... a lot of projects coming up for this vehicle.