I need an advice on my next Z4 purchase

[Nariman Latifov]

Hello,

I am a student in Turkey who plans to buy a Manual e85 Z4 from the USA. My primary purpose in buying a Z4 is %70 learn and master the dynamics of a car and %30 transportation. Based on my research, I have decided to go with a 3.0L 3.0i (3.0si if I can find one for a good price) because it will hold its value better. But the main question is whether to choose the 2003-5 M54 or the 2006-8 N52 engine. All I really want to know is which one will be more reliable, less problematic, and cheap to run. The power difference between the facelift and pre-facelift Z4 does not bother me since even 215 hp is more than enough for me in Istanbul.
I am planning to restore the engine when I buy the car. By that, I mean crank bearings, piston rings, head gasket, ignition coil, timing chain, and stuff because even the newest one is 15 years old already and I don't want to worry about any major problems. If anyone owned either N52 or M54 before, it would be useful if you let me know which mileage cars I should look for and how much more it will run approximately.
It will hopefully be my first car and I want it to be a good one. And before you recommend a Honda or Toyota as a first car, Z4 is the perfect car for me if either N52 or M54 is a good daily driver.

Looking forward to recommendations,

Sincerely,
Nariman Latifov.

[wdb]

I love the N52 motor. It's nearly bulletproof. You shouldn't need to rebuild it. You will want to do the usual stuff like oil pan gasket, oil filter housing gasket, water pump and other cooling system items. Otherwise just drive and enjoy. 3.0i can be tuned to 3.0si spec with an intake and tune, so a N52 3.0i might be your best bargain. Good luck!

[Piper1]

Welcome to the community.

We really do need a Non M buyers guide on the boards to answer some of these as well as other reoccurring questions.

To piggy back and answer some questions as said, unless you get something that was just totally abused you shouldn't have a need for a rebuild, both the M54 and N52 are very solid and have less maintenance concerns compared to the S54 in the M. Like any BMW valve cover gasket, oil filter housing gasket on both are very common and like any car cooling system and tune up/coils/plugs and basic odds and ends as needed.

I have a '07 3.0si coupe 34k miles and a '03 2.5 modded with the M54 109k miles as well as a 2011 128i 105k miles 3.0i non converted.

The M54/N52 are I'd say equally reliable with their own quirks but more quirks are noticeable in the pre vs. facelift in the over all car. If you get a N52 3.0i in comparing my 128 to the 3.0si coupe you'll want to make sure you either convert the 3.0i to SI or get a SI, there's a major difference comparing and the SI is well worth it and plenty of write ups out there to detail how/why.

Biggest thing I miss in my 03 vs the 07 is higher revving N52 when comparing just the engines.

Prefacelift:
PCV systems prone to collecting moisture especially if just driven short distances will create the valve to clog, milky oil similar to blow head gasket signs but easy/cheaper to replace the PCV system.

Facelift:
recall on the PCV heater which was designed to combat the issue in the M54 PCV also N52 PCV system integrated into the valve cover little more work and cost in replacing the PCV system in the N52 than in the M54. Short trips still can cause moisture in the N52 PCV to collect so the heater doesn’t cure the problem entirely.

Prefacelift:
rear springs notorious for breaking

Facelift:
ABS unit motor failure from inline change on ABS motor

Prefacelift:
TPS is gauged by tire revolutions not by sensors in each wheel so it’s easier/cheaper for aftermarket wheels.

Facelift:
TPS in each wheel and periodically needs replacement and added to aftermarket wheels or you get sensor error light if not tuned out but is more accurate of sensors than the revolution sensors in prefacelift.

All Roadsters can have issues with motor for soft top if water collects in the drains if clogged. Either clear the drains as a maintenance or relocate the motor to the trunk.

So it's not really one being better/more reliable than the other, but different with their own issues and quirks, to me you can't go wrong with either.

[Nariman Latifov]

That was a great answer to the question, thanks. I have one more question that probably you can answer the best. Based on the answers, my aim now is to get a facelift e85 Manual. But when it comes to buying a BMW with an N52 engine, should I look for a facelift Z4 under a certain mileage, and if yes, then how many miles is it? Also, how long does an N52 engine last and when do the major repair costs start?

[Piper1]

Originally Posted by Nariman Latifov

That was a great answer to the question, thanks. I have one more question that probably you can answer the best. Based on the answers, my aim now is to get a facelift e85 Manual. But when it comes to buying a BMW with an N52 engine, should I look for a facelift Z4 under a certain mileage, and if yes, then how many miles is it? Also, how long does an N52 engine last and when do the major repair costs start?

I’ve seen both come up for sale plenty over 200k for miles. Miles don’t kill these so much as neglect/abuse from the owner. You’re going to need to look for a well kept well maintenance documented car to reduce as many surprises you might encounter. What ever you find have a good ppi done prior to purchase. An abused/neglected garage queen with 40-50k miles isn’t as appealing as a 120k well maintained. Think rebuilt n52/m54 engines are around 4-5k ish if that lets you know how much it’d take to replace a blow engine. Think about how long you plan on keeping it to how much miles you plan to put on to cost of X miles you’re looking at to gauge if it’s worth the cost for higher vs X lower miles from a monetary value perspective, there’s just not a magic mileage number for what could go when vs say a bhg on a 7mgte from Toyota.

[jwolf]

First, everyone has their strong opinions on this. The m54b30 is the better engine in my opinion. It is more old school. The N52 has the electric water pump. The main reason is you can keep the m54b30 running longer. It has steel liner cylinders unlike the spray on coating of the n52. I just think it can be kept running longer with boring the cylinders etc., if needed one day. The n52 is a more complex engine that delivers what you expect with the generational change, but it comes with a cost.

[Efthreeoh]

Originally Posted by jwolf

First, everyone has their strong opinions on this. The m54b30 is the better engine in my opinion. It is more old school. The N52 has the electric water pump. The main reason is you can keep the m54b30 running longer. It has steel liner cylinders unlike the spray on coating of the n52. I just think it can be kept running longer with boring the cylinders etc., if needed one day. The n52 is a more complex engine that delivers what you expect with the generational change, but it comes with a cost.

Well, my N52 in the E90 has 419,000 miles on the original engine (no rebuild) and an average OCI of 12,400 miles. At that age and miles, the N52 consumes about the same oil quantity (1 liter every 3,200 miles) as the M54 in my 2005 E46 330ciC, which was at 100,000 miles when I bought it from a friend in late 2019.

While original WP failed at 149,500 miles, the replacement pump is now at 269,500 miles without a single speed code dropped into the ECU. The M54 in my E46 had a bunch of cooling system work done at 75,000 miles (a few hoses and the belt-driven WP). Also, I think the N52 VANOS solenoid system is less prone to failure vs. the M54. The N52 weighs less than the M54, which helps in ride and handling in the E85 chassis. The OP will be happy with either engine, but I think the best choice is the 3.0si.

[pungo]

Originally Posted by Nariman Latifov

I am planning to restore the engine when I buy the car. By that, I mean crank bearings, piston rings, head gasket, ignition coil, timing chain, and stuff because even the newest one is 15 years old already and I don't want to worry about any major problems.

That's pretty ambitious to plan on a complete engine rebuild before even finding/purchasing the car

Just so you know, age has very little effect if any for an engine requiring a complete rebuild due to worn bearings/rings/TC. Mileage, abuse and maintenance have more of a effect on an engine needed a rebuild than age. I well maintained N52 engine can go 300k miles or more before needed a rebuild.

[Efthreeoh]

The OP will need to rebuild the hydraulic top motor before he'll need to rebuild the N52 in the engine bay.

[Nariman Latifov]

Originally Posted by pungo

That's pretty ambitious to plan on a complete engine rebuild before even finding/purchasing the car

Just so you know, age has very little effect if any for an engine requiring a complete rebuild due to worn bearings/rings/TC. Mileage, abuse and maintenance have more of a effect on an engine needed a rebuild than age. I well maintained N52 engine can go 300k miles or more before needed a rebuild.

The reason why I am planning a rebuild is to future-proof it. I will register the car in Azerbaijan (where I am from) and take it to Turkey (where I live) and since my father is a mechanic in Azerbaijan, I thought giving the motor a rebuild will help me from the hustle of repairing it in Turkey in case something happens. I know that light maintenance aside, I will not have time and money for a rebuild if necessary. But based on the comments, seems like a rebuild will not be necessary in this case.

But is there anything else that you recommend to make the car more durable like relocating the soft top motor to the trunk and so on?

[Nariman Latifov]

Originally Posted by Efthreeoh

The OP will need to rebuild the hydraulic top motor before he'll need to rebuild the N52 in the engine bay.

Hopefully, the motor will be in a decent enough condition that relocating it will be enough to save it.

[Nariman Latifov]

Originally Posted by Piper1

I’ve seen both come up for sale plenty over 200k for miles. Miles don’t kill these so much as neglect/abuse from the owner. You’re going to need to look for a well kept well maintenance documented car to reduce as many surprises you might encounter. What ever you find have a good ppi done prior to purchase. An abused/neglected garage queen with 40-50k miles isn’t as appealing as a 120k well maintained. Think rebuilt n52/m54 engines are around 4-5k ish if that lets you know how much it’d take to replace a blow engine. Think about how long you plan on keeping it to how much miles you plan to put on to cost of X miles you’re looking at to gauge if it’s worth the cost for higher vs X lower miles from a monetary value perspective, there’s just not a magic mileage number for what could go when vs say a bhg on a 7mgte from Toyota.

That helped a lot, Cheers!!

[Nariman Latifov]

Originally Posted by Efthreeoh

Well, my N52 in the E90 has 419,000 miles on the original engine (no rebuild) and an average OCI of 12,400 miles. At that age and miles, the N52 consumes about the same oil quantity (1 liter every 3,200 miles) as the M54 in my 2005 E46 330ciC, which was at 100,000 miles when I bought it from a friend in late 2019.

While original WP failed at 149,500 miles, the replacement pump is now at 269,500 miles without a single speed code dropped into the ECU. The M54 in my E46 had a bunch of cooling system work done at 75,000 miles (a few hoses and the belt-driven WP). Also, I think the N52 VANOS solenoid system is less prone to failure vs. the M54. The N52 weighs less than the M54, which helps in ride and handling in the E85 chassis. The OP will be happy with either engine, but I think the best choice is the 3.0si.

To be hones, did not expect that much miles from a no rebuild N52. I guess it really comes down to the driver and the maintenance.

As I mentioned, I will hopefully register the car in one country and use it in another. Do you recommend anything specific before a long road trip in a newly purchased BMW?

[Piper1]

Originally Posted by Nariman Latifov

The reason why I am planning a rebuild is to future-proof it. I will register the car in Azerbaijan (where I am from) and take it to Turkey (where I live) and since my father is a mechanic in Azerbaijan, I thought giving the motor a rebuild will help me from the hustle of repairing it in Turkey in case something happens. I know that light maintenance aside, I will not have time and money for a rebuild if necessary. But based on the comments, seems like a rebuild will not be necessary in this case.

But is there anything else that you recommend to make the car more durable like relocating the soft top motor to the trunk and so on?

Big items to make sure are done as maintenance is everything cooling related, water pump, expansion tank, thermostat, hoses is what you're looking at something with decent miles, if not done that falls under the neglected owner status to avoid. If it's over 100k ish for miles and those aren't done move on to another. Those are the main things that would cause early failure and extra expense for you. Also DISA (M54 has 1, N52 3.0i has 1, 3.0si has 2 and easy to do yourself) and maybe vanos/seals/solenoids, any leaky gasket. The way to "future proof" these cars is to maintain them rather than rebuild them.

Going back through another post I've spent just under 10k in maintenance cost in the 12 years I've had my 03 and that includes tire cost. Some of those items too were preventative/supportive preparing for the mods I've done.

[Piper1]

Originally Posted by Efthreeoh

In the USA, most BMW convertibles are summer cars owned by wealthy people .

There's a quote floating around somewhere that everyone can afford a BMW, not everyone can afford to maintain them. I did daily my 03 for 4 or 5 years, when I had changed jobs and my new job salted the parking lot all to hell and back was when I decided I needed a different winter car to spare it from being aSalted

[JAS1169]

Hey

I'm guessing you really want a Z4, which is ok. Buying a USA model & transporting it back to your own country might be costly. Will your customs charge any fee's for importing it?

I'm sure the USA model and Z4's made for other parts of the world mostly share the same parts. However, I'm just as sure that due to pollution control, there are other parts made specifically for the USA model. Will you be able to source parts (if need) made for the American Z4 on a timely manner or will it take weeks to arrive.

If I were you, I'd really go with a European model of the Z4 only because of parts, as well as the time it may take for them to be shipped to your country.

Wish you luck with this.

[Piper1]

Originally Posted by JAS1169

I'm sure the USA model and Z4's made for other parts of the world mostly share the same parts. However, I'm just as sure that due to pollution control, there are other parts made specifically for the USA model. Will you be able to source parts (if need) made for the American Z4 on a timely manner or will it take weeks to arrive.

If I were you, I'd really go with a European model of the Z4 only because of parts, as well as the time it may take for them to be shipped to your country.

Wish you luck with this.

You bring a good point with emissions eu headers are different and the pre/secondary air warmer for O2s least for the M54.

[Nariman Latifov]

Originally Posted by JAS1169

Hey

I'm guessing you really want a Z4, which is ok. Buying a USA model & transporting it back to your own country might be costly. Will your customs charge any fee's for importing it?

I'm sure the USA model and Z4's made for other parts of the world mostly share the same parts. However, I'm just as sure that due to pollution control, there are other parts made specifically for the USA model. Will you be able to source parts (if need) made for the American Z4 on a timely manner or will it take weeks to arrive.

If I were you, I'd really go with a European model of the Z4 only because of parts, as well as the time it may take for them to be shipped to your country.

Wish you luck with this.

You are right about buying a car from the USA and transporting it to Eastern Europe. Z4 might be cheaper in some Western Europe countries, but the reason I want to buy it from the USA is because of my possible USA trip. It is still a 15-20-year-old car and purchasing a Z4 abroad without a good inspection will be a gamble I am not willing to take.

When it comes to buying one from where I live, in Turkey the prices are mental and the car culture is weird. 3.0 Z4 both post/pre-facelift starts from around 30.000$, plus most second-hand cars in Turkey are cosmetically (the engine bay too) well maintained but have serious mechanical defects that are nearly impossible to see unless you take it apart.

The third option would be to buy a car from Azerbaijan (Where I am from), we literally have no Z4s and have a few fun cabrios. Other fun options might be a restored e325/328 e36, occasionally some Mini s or Abarth 595. For this messy situation, a Z4 from the USA seems like the only right choice.

[Huz-Z]

The N52 uses magnesium in the engine block so the engine block weighs less than in pre facelift cars, which means more nimble steering.

It also means that the engine can’t accommodate the extra strain of a turbo or supercharger. So if you want to mod the engine for big power gains the pre facelift car is the one for you.