[scbim]

I know there's been a lot of discussion about this but I'm looking for some fresh perspectives (especially from anyone with 150k+ miles). I've got 108k on my 2007 335i; the clutch is failing and the wastegate rattle is getting worse. What's on the table currently is replacing the clutch, flywheel, turbos, water pump, thermostat, brake lines, intake valve cleaning, and OFHG. Will be doing all the work myself since paying for labor would probably bankrupt me. My only concern is how much else I can expect to deal with in the coming years as more parts start to fail and what kind of mileage I can expect to get out of the engine itself. Haven't really heard of anyone with over 200k on these cars which is concerning. Plenty of e39s out there for instance with 300k+ (my buddy has one with around 215k running strong and still hardly demanding any serious maintenance).

Already upgraded the suspension and a number of odds and ends so I'm wondering, if I go all in will it bite me in the ass or should I just bite the bullet and sell it for something a little more manageable like an e36 or e46?

[pmsteinm]

My wife's 07 got to 140k before we sold it for her X5. Around 100k I did thermostat and water pump speculatively, replaced leaking oil pan gasket, and had to replace the injectors. Other than that just routine maintenance. Earlier I did the oil filter housing gasket. It was leaking oil for the last 40k at the turbo oil lines. But I read that could be the gaskets or an internal turbo failure. Since the only way to find out is to remove them I wasn't going to do all that work then have to wait if I needed to order turbos. I let it leak for years. Never got a check engine light or failure so it probably was just the oil line gaskets.

The car needed a clutch at 80k but that's probably because it was my wife's first manual.

It seemed like a pretty solid car aside from some plastic bits getting brittle with age. One more reason I say to put miles on a car. Even if you save it everything still gets old and may fail due to age.

[pmsteinm]

Oh and I forgot to add that I did the oil changes when the computer said to. So around 16k each including the first. Did that cause more oil leaks? I wonder. Or do the Germans aspire to be like the British?

[pete9903]

Originally Posted by pmsteinm

Oh and I forgot to add that I did the oil changes when the computer said to. So around 16k each including the first. Did that cause more oil leaks? I wonder. Or do the Germans aspire to be like the British?

I highly recommend shorter intervals. My independent shop (BMW only for 30+ yrs), still recommends 5k changes due to the detergents in synthetic oil starting to break down by then. I'm somewhere between 5-7500.

From Mike Miller's "Old School BMW Maintenance Schedule" (download if you want a good read!)

"But once BMW began paying for scheduled maintenance, lo and behold the “schedule”
was revised. Now the cars hardly need any maintenance at all. The 1,200-mile break-in
service was done away with except for M cars. Engine oil suddenly lasts 15,000 miles
(dealers are supposed to use BMW synthetic oil)."

[335i54n]

I wouldnt do long interval cause i drive my cars hard but have seen those that follow bmw recs with bmw specified oil (never run low) and have no issues.

n54 at this point is almost dying imo cause the b58 is so great, just needs to drop in price a little more. e90 size, chassis and Hydraulic steering is whats keep me.

op already have index 12? probably expect radiator, expansion tank, fan and I would just adjust the wastegate for now. imo e36/e46 is too old and costly for the premium ones, i would look for an n52 powered bmw instead

[scbim]

Originally Posted by Efthreeoh

I'll chime in, not about the N54 question much since I've only owned two N52, but about the E90 chassis longevity. Every use case is different of course, but I have a 2006 325i with 421,000 miles. While the N52 is not a turbo engine, I did follow the CBS oil change schedule and from 0 to 221,000 miles the OCI was 16,343 miles. My use case has changed starting in 2022 going to an annual oil change at around 5,000 miles. Over my 34 oil changes the OCI is 12,322. I used only BMW oil and oil filters. While the N54 is forced induction, I don't think extended oil changes affect engine longevity that much differently than for the non-turbo N52. I have no data for that position other than just simple automotive engineering principles. The key to good lubrication performance is engine oil system design, oil filter performance and oil chemical composition. The N54 is not really much different than the N52 in those parameters. I think an N54 easily reaches 200,000 miles with not much mechanical correction. There is a thread on E90 post about highest miles on the N54. There are lot of owners who reached well over 200,000 miles.

Onto the chassis. Being our cars are nearly identical in age I thought a discussion regarding the chassis life at high mileages would be interesting to you. Basically, you are at the 100,000 mile BMW refresh stage and questioning if the effort is worth it considering the age of the car (overall). My car has nearly 4x the miles your car does. I've never used my car for family transport of little kids, which can tear up an interior like a pair of fighting wolverines, but I did have two beagles in it numerous times and monthly transport of 4 adults on a daily business trip for about 10 years straight. For 8 years my E90 was my daily 165 round trip commuter 5 days a week, then 7 years for 3 days a week. And I live in the mountains west of Washington DC, so my commute was rural mountain roads to urban DC stop and go traffic. Trust me, I hammered the car on the excellent track-level rural mountain roads I get to drive on and still do.

I refreshed the suspension with BMW OE parts in 2021 just 17,000 miles ago (similar to your situation*). All of the rear suspension bushings are original except for the outer lower control arm ball joint bushings; the right rear failed at 410,000 miles. The engine mounts are original. The trans mounts are 200,000 miles old and didn't need replacement when I replaced them. As it sits now I have a $400 (used) rear subframe to replace the deteriorated one in my car that has significant rust; I'll swap it here in a few weeks once the August heat and humidity dies away.

As most all my other BMWs the E90 is very well built and long lasting. I have the Sensatec interior and it has lasted extremely well. I did replace the upper driver's seat cover in 2012 at 170,000 miles. The seat bottom is original; "lightweight" is not a descriptor of my weight class. From 2006 to 2015 it spent its life covered both at home and at work under a carport and parking garage respectively. Since 2015 it has been parked in the sun partially during the day when not in use. At 421K the only body issues are degrading front and rear window surrounds and the radio face blanks out from heat; both easily fixable.

Long read, sorry, but my point is the E90 chassis is so well built and durable its worth keeping the mechanicals in shape. Now, in your list I have to question replacement of the brake lines (do you mean the brake hoses?) and waterpump and t-stat. And intake valve cleaning on an N54? IIRC the N54 is not direct injection and I've not read where intake valve oil coking is an issue. I do not know how annoying wastegate rattling is. *If the suspension fresh, I'd heavily take that into consideration. My opinion based on my 35 years of BMW ownership is your car easily has another 100,000 miles in it. If you DIY, you can keep a BMW for a very long time for not much expense.

Hope this helps.

Thanks for the detailed reply mate, that was encouraging and very informative. 410k, no kidding! I'm impressed.

To answer your question, I did mean brake hoses, mine are cracking so I'm replacing them with steel ones. I actually preemptively bought the water pump and thermostat but am waiting for the computer to throw a code since the job looks...unpleasant. The turbos are definitely an issue but new ones should last the life of the car since the main point of failure is the wastegate on earlier models--however, that is also a beast of a job and the units are pricey, around $1k each. I'm thinking about adjusting the actuators which I've heard is a temporary fix but some say it causes turbo lag, so, still looking into that.

The N54 is DI actually, many recommend carbon cleaning as often as 30-50k. Messy job but doesn't appear particularly challenging. Clutch replacement is first on my list. Almost certain the thing is burnt at this point, no choice but to replace it since it isn't in selling condition until I do, but, that said, I'm looking forward to enjoying the car for a good while longer at the very least.

Does the N52 use VANOS? My buddy keeps warning me about VANOS failure, but I haven't read about anybody running into major issues with it other than the solenoids which are pretty easy to replace.

Sounds like you haven't run into any big oil leaks either?. Can be a hassle chasing after those, I'll do the rear main seal when I swap the clutch and the OFHG when I clean the intake valves.

At any rate, thanks again for the info! Definitely feeling a bit more at ease.

[scbim]

Originally Posted by pmsteinm

My wife's 07 got to 140k before we sold it for her X5. Around 100k I did thermostat and water pump speculatively, replaced leaking oil pan gasket, and had to replace the injectors. Other than that just routine maintenance. Earlier I did the oil filter housing gasket. It was leaking oil for the last 40k at the turbo oil lines. But I read that could be the gaskets or an internal turbo failure. Since the only way to find out is to remove them I wasn't going to do all that work then have to wait if I needed to order turbos. I let it leak for years. Never got a check engine light or failure so it probably was just the oil line gaskets.

The car needed a clutch at 80k but that's probably because it was my wife's first manual.

It seemed like a pretty solid car aside from some plastic bits getting brittle with age. One more reason I say to put miles on a car. Even if you save it everything still gets old and may fail due to age.

Oil leaks can be a bitch, especially at the turbos. Did you ever run into wastegate rattle or adjust the actuators? I'm getting a rattle sound with moderate acceleration just over 2k RMPs, fairly certain it must be the wastegate since I know it's a common issue. My guess is that it rattles when there is just enough pressure to open the gate but not enough to keep it fully forced open. The dealership told me they addressed a wastegate rattle earlier in the car's life (around 60k I believe), but I think they typically do that through the car's computer. Curious how adjusting the actuators will affect the system considering the prior adjustment...

[pmsteinm]

There was a warranty issue with waste gates early on. They replaced the actuators. They also replaced the cam shaft bearing ledges at that time. And it needed two HPFPs until we got a good one that then lasted 100k+. All that was factory warranty stuff and seemed like known issues with the 1st year of the N54.

When we sold it ran fine. I hardly ever drove it so if it was having other rattles or issues it's possible my wife would not have noticed.

[pmsteinm]

Oh and I did the valve cleaning 3 times. The first time tried chemicals and that sucked. Next 2 times I used the walnut blaster and that was easy. Slow part was just disassembly to get to it.

[scbim]

Originally Posted by Efthreeoh

410K was the rear bushings, the car has 421K.

The N52 uses both Valvetronic and VANOS. I clean and swap the VANOS solenoids every 50,000 miles. I'm assuming the N54 solenoids can be swapped. The theory is the exhaust and intake cams use different VANOS profiles, so swapping the solenoids lets them run differently between swaps. Again, my theory I came up with some 15 years ago.

I had the trifecta of oil leaks. OFHG twice. The valve cover did not have a leak, I did it because I replaced the Valvetronic eccentric shaft sensor (the N54 does not have it). I posted a pretty decent DIY on the clutch for the N52 but I'd bet the N54 is nearly the same. Prep yourself for rusted exhaust flange bolts where the rear pipe bolts on the headers.

Good luck with it. A 100,000 mile BMW 3-series is just breaking in IMO.

If you are going to DIY the clutch, hell, I'd do the other items on your list and keep the car. IMO the E90 was the last of the classic 3-Series.

BTW I just joined the DI turbo club last year. I bought a Ford Bronco 2.3 manual. I guess at some point a walnut blasting is in my future.

Welcome to the club! Been thinking about the best way to clean those intakes without making a huge mess...BimmerBarn on YT used fuel injector cleaner and compressed air towards the end which blew gunk all over his engine bay and face...May end up just doing a slightly less thorough cleaning and settle with microfiber towels to get most everything out of there.

My mechanic buddy drove my car and said he thinks there's a hotspot on the flywheel that's causing the slippage, so, looks like I'll be replacing both - figured I might as well do the clutch slave, hose, and transmission mounts while I'm at it...AND planning to upgrade the shifter with a custom build from Ronald at AutoSolutions as well - glowing reviews from everyone who's interacted with him. Sent an inquiry email a few days back and he responded with a boatload of super helpful information.

VANOS solenoids probably long overdue for some attention...seems like the mechanical parts are pretty solid and they can just be cleaned and gaskets replaced so planning to go that route for now. The list goes on....sigh

Thanks again for all the tips and encouragement. At this rate I'll likely stay with the 335 for many years to come, she's a lovely machine despite the quirks.

[pete9903]

Originally Posted by Efthreeoh

The Mike Miller schedule is a bunch of BS. IMO (based on 35 years of BMW experience).

Not all BS, his points about "lifetime fill" fluids are valid. Glad you've gotten so many miles out of your 325i, I'm hoping for the same.
(OP, sorry for the thread drift..)

[pete9903]

Originally Posted by Efthreeoh

Miller's schedule is nothing more than BMW's normal maintenance schedule used by the company up to the mid 1990's. Manufacturing techniques and fluid chemistry have vastly improved since the 1970's. Yet even in the 1980's BMW was using extended engine oil service intervals based on condition-based protocols. My E30 routinely went near or up to 10,000 miles on engine oil changes as does my wife's Z3 that remains in the fleet 26 after we bought it new in 1997.

Last counterpoint I'll make is that on my '87 635 (owned for seven years), I waited to get to the red CBS light for the first couple oil changes, and that oil came out DARK. I started changing it when I got down to the yellow lights, and it looked much less cooked (this was before I knew about Blackstone Labs, so I can't offer real data but color is an indicator). Always used full synthetic, proper weight. Mike Miller certainly takes a conservative approach that is overkill on some items for modern cars, but I will always be wary of anything that says "lifetime fill."

[whyzee125]

The N54 is a strong engine and the car is much better built than most new stuff on the road. IMO fix it. Lots of 200k+ N54's out there, many of them tuned for the majority of that. There's a guy that works for BMS (Payam I think?) and he bought one with over 300k and went single turbo with it and it was running strong for a long time.

N54 maintenance kind of comes in waves and you're hitting a wave right now but it should be smooth sailing for a while after if you take care of all its current needs. 108k isn't a lot at all for these.

[scbim]

Originally Posted by whyzee125

The N54 is a strong engine and the car is much better built than most new stuff on the road. IMO fix it. Lots of 200k+ N54's out there, many of them tuned for the majority of that. There's a guy that works for BMS (Payam I think?) and he bought one with over 300k and went single turbo with it and it was running strong for a long time.

N54 maintenance kind of comes in waves and you're hitting a wave right now but it should be smooth sailing for a while after if you take care of all its current needs. 108k isn't a lot at all for these.

Thanks for your $0.02 friend, I'm all in! New clutch and flywheel on the way, replacing the clutch master/slave, upgrading to a steel-braided line, fresh transmission mounts, plus a short-shift kit from Ronald at AutoSolutions (he's amazing btw, if you ever decide you want to upgrade I highly recommend him). After cleaning the intake valves and replacing the OFHG, I hope to be coasting for a good while.

[Raghza]

Wait, 108k miles is considered high mileage?