Questions about N51 SULEV cars

[roarf]

I am considering buying a 128i to replace my E39 as my second car. Have a few questions about cars with the N51 though. I've looked over the list of differences between the standard 128 and the SULEV 128. I think I am up to speed on the differences between the engines themselves (N51 vs. N52), but had a few questions about the other SULEV related stuff.

1) Fuel pump - It looks like the pump can still be replaced separately (don't have to replace the entire fuel tank assembly). Can anyone confirm?
2) Stainless steel fuel lines with threaded connections - What are they normally made out of? Why stainless in the SULEV application?
3) Radiator with “Prem-air” coating - I'm familiar with what the coating does but does it affect the efficiency of the radiator at all? Is the radiator identical to the N52 radiator, aside from the coating?
4) Purge system pipes are made from “optimized” plastic - What is "optimized" plastic? What are they referring to when they say "purge system"? Is that related to the fuel evap system?

Anything else noteworthy I've missed? My main concerns are longevity and cost for the SULEV specific components. Can anyone comment on this?

I would prefer a N52, but if a N51 car with all the right options came up, I want to know what to expect. Thanks in advance.

[TheSt|G]

Originally Posted by roarf

I am considering buying a 128i to replace my E39 as my second car. Have a few questions about cars with the N51 though. I've looked over the list of differences between the standard 128 and the SULEV 128. I think I am up to speed on the differences between the engines themselves (N51 vs. N52), but had a few questions about the other SULEV related stuff.

1) Fuel pump - It looks like the pump can still be replaced separately (don't have to replace the entire fuel tank assembly). Can anyone confirm?
2) Stainless steel fuel lines with threaded connections - What are they normally made out of? Why stainless in the SULEV application?
3) Radiator with “Prem-air” coating - I'm familiar with what the coating does but does it affect the efficiency of the radiator at all? Is the radiator identical to the N52 radiator, aside from the coating?
4) Purge system pipes are made from “optimized” plastic - What is "optimized" plastic? What are they referring to when they say "purge system"? Is that related to the fuel evap system?

Anything else noteworthy I've missed? My main concerns are longevity and cost for the SULEV specific components. Can anyone comment on this?

I would prefer a N52, but if a N51 car with all the right options came up, I want to know what to expect. Thanks in advance.

As a baseline, there are very few high mileage SULEV cars out there, so we really do not have a sampling of what the part longevity is. That being said,
we can answer/guess a few of your questions:

1) Fuel pump can be replaced separately, regulator requires full gas tank/line replacement.

2) Fuel lines are generally plastic. I would assume they used SS in this application to reduce fuel vapor emissions, as that is one of the primary purposes of the SULEV cars.

3) I would assume it's serving a similar purpose, but for coolant leaks.

4) Unfamiliar.

If you are really in it for the long term, there is no doubt that the N52 would be the better choice. Personally I would(and did) wait for the right engine.

[Suprgnat]

Originally Posted by roarf

I am considering buying a 128i to replace my E39 as my second car. Have a few questions about cars with the N51 though. I've looked over the list of differences between the standard 128 and the SULEV 128. I think I am up to speed on the differences between the engines themselves (N51 vs. N52), but had a few questions about the other SULEV related stuff.

1) Fuel pump - It looks like the pump can still be replaced separately (don't have to replace the entire fuel tank assembly). Can anyone confirm?
2) Stainless steel fuel lines with threaded connections - What are they normally made out of? Why stainless in the SULEV application?
3) Radiator with “Prem-air” coating - I'm familiar with what the coating does but does it affect the efficiency of the radiator at all? Is the radiator identical to the N52 radiator, aside from the coating?
4) Purge system pipes are made from “optimized” plastic - What is "optimized" plastic? What are they referring to when they say "purge system"? Is that related to the fuel evap system?

Anything else noteworthy I've missed? My main concerns are longevity and cost for the SULEV specific components. Can anyone comment on this?

I would prefer a N52, but if a N51 car with all the right options came up, I want to know what to expect. Thanks in advance.

3) According to BASF: "There is no significant impact on cooling or other performance attributes of the radiator."

http://www.basf.com/group/corporate/...al-English.pdf

If you lived in California I wouldn't worry too much about the N51 as the CARB mandates something like a 10 year warranty on emissions related parts. I have no idea how that translates in Indiana...

[TheSt|G]

Originally Posted by Suprgnat

3) According to BASF: "There is no significant impact on cooling or other performance attributes of the radiator."

http://www.basf.com/group/corporate/...al-English.pdf

If you lived in California I wouldn't worry too much about the N51 as the CARB mandates something like a 10 year warranty on emissions related parts. I have no idea how that translates in Indiana...

I'm 99% sure BMW honors that in any state.

That said, you are talking to a guy who has a 12-13 year old 5 series, so he isn't a short term owner.

[Suprgnat]

Originally Posted by TheSt|G

I'm 99% sure BMW honors that in any state.

That said, you are talking to a guy who has a 12-13 year old 5 series, so he isn't a short term owner.

True dat.

[roarf]

Originally Posted by Suprgnat

3) According to BASF: "There is no significant impact on cooling or other performance attributes of the radiator."

http://www.basf.com/group/corporate/...al-English.pdf

If you lived in California I wouldn't worry too much about the N51 as the CARB mandates something like a 10 year warranty on emissions related parts. I have no idea how that translates in Indiana...

Hm, good to know. Just wondering because if the N52 radiator was the same dimensions, a person could just replace with one of those if that was ever needed (and it's cheaper).

Originally Posted by TheSt|G

I'm 99% sure BMW honors that in any state.

That said, you are talking to a guy who has a 12-13 year old 5 series, so he isn't a short term owner.

That was going to be my next question. Do we know for sure if BMW will honor that warranty in any state, regardless of original owner or not?

For the record, I am not the original owner of either of my cars. That being said, if I like a car I will probably want to keep it for several years. I currently have no plans to sell my M3.

Next question.. Did the 128 get both the N52 and the N52KP (N52N), or just the newer revision?

[TheSt|G]

Just the N52N, but the engine did get some revisions in 2009 as well.

[jclaib7]

[QUOTE
Anything else noteworthy I've missed? My main concerns are longevity and cost for the SULEV specific components. Can anyone comment on this? [/QUOTE]

I could be wrong, but I believe the N51 also has a carbon filter in the airbox, which I cut out with a dremel when I upgraded to the performance intake.

[MarkkyyMan]

That filter is so dumb.

[chris82]

I have the N51. It does have a charcoal filter in the engine intake box. It's pretty dumb; the previous owner cut mine out before I could do it myself . . . It only has 32000 miles on it, 21 of which were from me. Can't say anything other than I have had no issues yet (can someone else knock on wood for me?)

[bozola]

I have 84k on my N51. I have had no issues in the last 2 years. A spate of issues just after warranty, but that's it. Crosses fingers.

[m_thompson]

Originally Posted by roarf

Just wondering because if the N52 radiator was the same dimensions, a person could just replace with one of those if that was ever needed (and it's cheaper).

There is a sensor in the ECU that looks for the PREM coated radiator. If it doesn's like what it sees it turns on the CEL.

[MarkkyyMan]

Originally Posted by bozola

I have 84k on my N51. I have had no issues in the last 2 years. A spate of issues just after warranty, but that's it. Crosses fingers.

What issues did you have? If you don't mind me asking.

[roarf]

Originally Posted by m_thompson

There is a sensor in the ECU that looks for the PREM coated radiator. If it doesn's like what it sees it turns on the CEL.

How would it know that? Not sure if serious...

[bozola]

http://www.1addicts.com/forums/showthread.php?t=784334

[Suprgnat]

Originally Posted by TheSt|G

I'm 99% sure BMW honors that in any state.

That said, you are talking to a guy who has a 12-13 year old 5 series, so he isn't a short term owner.

My bad, but FWIW the SULEV emissions equipment is 15 years/150 k miles.

[Fume]

Originally Posted by TheSt|G

I'm 99% sure BMW honors that in any state.

That said, you are talking to a guy who has a 12-13 year old 5 series, so he isn't a short term owner.

I wish that was true. It's not unfortunately. From the warranty booklet for US:

Certain 2013 128i and 328i models are certified
to California’s stringent Super Ultra Low
Emission Vehicle (SULEV) standards and also
qualify as a Partial Zero Emission Vehicle (PZEV)
under the California Air Resources Board Zero
Emission Vehicle program. In addition to very low
tailpipe and zero-evaporative emissions, this
PZEV certification includes a unique warranty
when the vehicle is registered in California,
Connecticut, Maine, Maryland, Massachusetts,
New Jersey, New York, Rhode Island or Vermont.
The SULEV (PZEV) models registered in Oregon,
Pennsylvania and Washington are covered by the
California Emissions Warranty; this coverage is
described beginning on page 28.

I bolded the relevant section. If you're unlucky and live in Oregon, Pennsylvania, or Washington state, you only get the 7 years/70000 miles warranty on some parts and the 8 years/80000 miles warranty on other specific emissions parts.

[TheSt|G]

All the more reason to skip it as a long term purchase.

[m_thompson]

When my 128i had a CEL on, the dealer said that as the car aged the PREM coating changed a little and the ECU didn't like the radiator sensor reading. The dealer did a software update to the ECU to change the sensitivity of a sensor that looked for the PREM coating on the radiator. The dealer said that the PREM radiator was part of the SULEV emissions so the ECU made sure that it is in place and working.

Other forums refer to a 2AD8 fault and the radiator sensor as an EAC (Environmental Air Catalyst) sensor, and say that the sensor is brazed to the radiator core.

[roarf]

Originally Posted by m_thompson

When my 128i had a CEL on, the dealer said that as the car aged the PREM coating changed a little and the ECU didn't like the radiator sensor reading. The dealer did a software update to the ECU to change the sensitivity of a sensor that looked for the PREM coating on the radiator. The dealer said that the PREM radiator was part of the SULEV emissions so the ECU made sure that it is in place and working.

Other forums refer to a 2AD8 fault and the radiator sensor as an EAC (Environmental Air Catalyst) sensor, and say that the sensor is brazed to the radiator core.

Ah. Well that's lame.

What mileage was that at?

[m_thompson]

Originally Posted by roarf

Ah. Well that's lame.

What mileage was that at?

I would need to go through the service records to find the exact details, but it was about 3 years old and about 15,000 miles.

[Pkaia524]

I have a 2008 128i with the N51. It will turn 134,000 miles tomorrow. Absolutely zero problems with the car.

I bought the car with 35,000 miles on the odometer in Nov. 2011. One previous owner.

I replaced the mass air sensor at 90,000; my mechanic said I caused its premature demise because I cleaned it with MAS cleaner (it was working just fine before I sprayed it).
I replaced the water pump/tstat at 120,000 preventively.
I replaced struts/shocks/front control arms at 130,000 (first time they were replaced).
All other work has been wear/tear items (brakes, tires, coolant, etc).

Again, no problems with emissions, engine internals, etc. No concerns here about longevity.

In case you are interested, I track all the expenses. Maintenance costs are 7.4 cents/mile. Operating (maintenance/fuel/insurance) costs are 20.7 cents/mile. Full costs (add depreciation to above) are 32 cents/mile.