Z4M Head Gasket Leak @ 50k?

[The_Ring_Monster]

Hi,

While checking out a Z4M, my friend who's an experienced technician noticed a small leakage of oil from the front of the head gasket going all the way back. He advised me that this may be due to a bad head gasket and will need a engine rebuilt ($2000 job) and the car will need a new (coolant?) pump...After coming home I did some research and found that this type of leak is often misdiagnosed as a head gasket leak when in fact it is a simple fix... Valve cover gasket.

To be honest, the car looks like a champ in my eyes but I'm no expert when it comes to this level of detail. The Z4M has only about 50k miles and seems to be well maintained. What are your opinions on this? Is this a common problem among the N54s out there?

[pokeybritches]

There's another leak that's usually misdiagnosed, but I can't remember what the name is (CPV or or something). Do a search for head gasket leak and it will come up.

You don't want to get into an engine rebuild on a Z4M because it requires a very high level of skill to do the job properly... very high as in, I only know of a few shops in the country that will do it right with minimal risk. It requires special tools, knowledge, and extreme attention to detail.

Fortunately, that leak is probably not from the head gasket.

[Beedub]

failures do happen but its not a common fault on th s54 motor.

[The_Ring_Monster]

What is the best way to check to see if there is indeed a head gasket failure? Compression test?

[mhughett]

Originally Posted by The_Ring_Monster

Hi,

While checking out a Z4M, my friend who's an experienced technician noticed a small leakage of oil from the front of the head gasket going all the way back. He advised me that this may be due to a bad head gasket and will need a engine rebuilt ($2000 job) and the car will need a new (coolant?) pump...After coming home I did some research and found that this type of leak is often misdiagnosed as a head gasket leak when in fact it is a simple fix... Valve cover gasket.

To be honest, the car looks like a champ in my eyes but I'm no expert when it comes to this level of detail. The Z4M has only about 50k miles and seems to be well maintained. What are your opinions on this? Is this a common problem among the N54s out there?

With all due respect to your friend, I don't think he knows what he is talking about. If you are seeing oil leaking around the engine, it is from the valve cover gasket, not the head gasket. The head gasket is designed to keep the oil out of the cooling system inside the engine. If the head gasket were to be leaking, it would allow coolant to mix with the engine oil, which you would see if you pulled the dipstick or removed the oil filler cap. It would look kind of milky in the oil. But I agree with the opinions above that the S54 engine doesn't normally have head gasket problems unless it has been overheated.

[polar]

Any updates?

[Flying Scotsman]

Originally Posted by mhughett

With all due respect to your friend, I don't think he knows what he is talking about. If you are seeing oil leaking around the engine, it is from the valve cover gasket, not the head gasket. The head gasket is designed to keep the oil out of the cooling system inside the engine. If the head gasket were to be leaking, it would allow coolant to mix with the engine oil, which you would see if you pulled the dipstick or removed the oil filler cap. It would look kind of milky in the oil. But I agree with the opinions above that the S54 engine doesn't normally have head gasket problems unless it has been overheated.

While i do agree it is more likely to be the valve cover, i don't completly about your comment about the head gasket. Your description only covers IF the the gasket happens to blow through an oil gallery and water jacket. But it can blow from the cylinder to the water jacket, can tell by starting the car, removing the rad cap and look for tiny bubbles and can even smell the exhaust fumes from the rad. Or it can miss the oil and water altogether and vent straight out the side, usually feel the loss of power and hear it after lifting the bonnet and if left long enough will see the soot around the leak.