Things to check on '06 BMW 330xi (E90) before purchase ?

Hi everyone,

I've found a 2006 BMW 330xi (E90) that warms the cockles of my heart ... low miles for its age (<100K), 6-spd manual, & AWD. Graphite exterior & Dakota interior.

I'm going to see it tomorrow, and this being my 1st BMW, I'm looking for any advice, suggestions & recommendations on things to watch for during the inspection & test-drive.

I'm already thinking to check these things:

 - HVAC blower function

 - window regulators

 - VANOS solenoids (but how to check?)

 - water pump (also, how to check?)

I'd appreciate any thoughts or input!

Thanks,

  -- Pete

There's really no way to check the water pump. When I bought my E82 w/ 100k miles on it, I simply replaced the pump and thermostat proactively. It's a PITA, but at least it's done.

If there are service records available, consider it a huge plus. If not, you can still get a record of anything done at a dealer by having your local BMW shop pull the maintenance history.

According to my indy, the N52 is fairly bulletproof. Oil leaks are fairly common from the valve cover and the oil filter housing gasket, coil packs die, and of course the water pump is problematic, but other than those issues (all of which are straightforward to correct) they're solid. The one big potential danger - thankfully easy to detect and fix - is the accessory belt. If the tensioner or idler pulley starts to fail, the belt will walk off, destroy itself, and frequently get sucked into the front crank seal, pretty much guaranteeing that you will be buying a new motor. If the belt is even slightly off-center on the pulleys, replace it immediately with OE parts.

Suspension may well be worn (factory dampers only seem to be truly good for about 50k miles), but how much that bothers you will determine how soon you need to consider replacement.

The only time I've seen the valve covers leak is when the bolts break.  They are aluminum and the torque spec is 4 Newton-meters plus a certain number of degrees.  Five Newton-meters will break them.  If I owned one, i'd back out the broken bolts with a screwdriver and put new ones in rather than dealing with the Valvetronic motor and replacing all >20 valve cover bolts.  The gasket is metal, it theoretically shouldn't ever go bad.

That said, I hate the E90 interior, especially the seats, and would only own an E90 if someone gave it to me for free.

Belt tensioner tends to be a 70,000 mile consumable. It ticks, but it can be kind of hard to tell of there’s a lot of valve train noise going on, which the engines are also prone to.   Easy replacement job though. 

Thanks, all, for your quick replies!

While I have the VIN for the car, I can't seem to get the service history. The BMW dealer closest to me said they only have records of cars that have been in their shop - not the ability to search nation-wide. I did a carfax and found mostly records of inspections - minimal service records.

I'm aware of the oil leak issue around the valve cover & oil pan on the N52 motor ... was going to look for any signs of that.

Also the waterpump; since the history is unknown, I'll assume it hasn't been done & try to use that in negotiations on the price.

I was not aware of the accessory belt issue - thanks 02Pilot for that one - will definitely be on the look-out for that!

Knurled, I don't think I have the same aversion to the seats that you do, but I'll take it on a bit of a drive just to be sure, before I make a deal.

You guys are great!

Seats are definitely one of those things that are personal taste. 

PeteD said:

While I have the VIN for the car, I can't seem to get the service history. The BMW dealer closest to me said they only have records of cars that have been in their shop - not the ability to search nation-wide. I did a carfax and found mostly records of inspections - minimal service records.

Nonsense. If they are a BMW dealer, they're in the network and can pull all the records on the car. They may not want to, but it's possible. Takes five seconds. Hell, I've had my local dealer pull records on cars I've been considering even before purchase (they're technically not supposed to do that, but some will if you speak nicely to the right people).

No records on the car should be a major negotiating point. List everything that you will have to do and how much it will cost to make it right.

Make sure everything inside the car works too, as that can get rather spendy to fix. Check that all four windows roll up and down quietly, check the navigation system (if the car is equipped with one), check the sound system, adjust the seats in every single way, and press every single button that you can find. I've been able to negotiate good discounts by finding non-working things in the interior.

Also, check both diffs to make sure they're not leaking or weeping, and check the rear tire tread carefully— BMW's have a fairly aggressive factory camber setup in the rear that always wears out the inner part of the rear tires much more quickly than outer parts. A friend and I bought a 2002 540it a few weeks back and while the tread on the rear tires appeared to be fine, the inner parts were worn down to the metal, yikes!

Aaaand make sure that the transmission has actually been serviced recently.

Some people were/are still in the mindset of 'Lifetime' fluids being a thing.

I toss in a ditto on checking the diffs for leaking.  Out of a sample of three E9x's I've dealt with, there's been 2 rear pinion seals leaking and 1 forward diff pinion seal.

Leaking forward diff can turn into a big deal-- there's not much more than a teacup of fluid in there to start with.

And as an additional note, the transfer case is more of a pain than it should be to change the fluid in, due to access to the fill port.  And it will want to go to the dealer afterwards for a reset of the ECU.

Yeah, and unlike an old American car where you can pretty much rebuild the diff with the car up on jack stands, the BMW diffs need to be removed to service them, which usually means removing them with the subframe. As you can imagine, that can get quite costly if you pay somebody to do it.

I wrote car reviews for a car sales company a few years ago. I test drove an E90 once that was spewing oil out of the valve cover gasket after spirited driving. I've never seen a car so forcefully ejecting oil from the engine. I'm not sure if a bolt was broken or not, but I recommend driving the car with gusto before looking under the hood. 

All good advice here.  We have a 2006 in the family.  Also two other cars with N52 motors.

Oil pan gasket is really expensive to replace.  Whole subframe has to come off.  Our starter puked at about 70k, again really expensive to replace because there is mondo disassembly just to get to it.  One rear shock rusted IN HALF in 6 years, here in Virginia where it's not salty.  The water pump failed, the belt tensioner failed, at least one of the oxy sensors too.  A brake job is highway robbery, but you can do it yourself easy.

I will say, all the N52 motors we have are coming back with oil analysis results that look like motors twice their age.  I'm starting to wonder where all the iron, lead, copper, and aluminum are coming from . . . .

JBasham said:

All good advice here.  We have a 2006 in the family.  Also two other cars with N52 motors.

Oil pan gasket is really expensive to replace.  Whole subframe has to come off.  Our starter puked at about 70k, again really expensive to replace because there is mondo disassembly just to get to it.  One rear shock rusted IN HALF in 6 years, here in Virginia where it's not salty.  The water pump failed, the belt tensioner failed, at least one of the oxy sensors too.  A brake job is highway robbery, but you can do it yourself easy.

I will say, all the N52 motors we have are coming back with oil analysis results that look like motors twice their age.  I'm starting to wonder where all the iron, lead, copper, and aluminum are coming from . . . .

Speculation, but I wouldn't be at all surprised if the high wear metals in the oil are on cars that followed BMW's asinine maintenance schedule. 15k miles on engine oil? No thanks. I've seen under the valve covers of engines (M5x-series) that had the oil changed only when the monitors said to - it's ugly. With a lifetime of 5k-mile intervals, the valvetrain on my N51 is spotless. I got my previous M54 there without too much difficulty, but it wasn't bad at all (unknown history before it came to me). At least you can see the valvetrain on the N5x motors by just pulling the oil filler cap.

Yeah, don't ever follow the BMW oil change intervals. Change the oil every 5-6k miles with a good synthetic. My 2000 540it has 196k miles on it and the valvetrain looks spotless thanks to 6k oil change intervals. Meanwhile a 2001 740i that was always dealer-serviced with BMW intervals had tons of brown crud in it. The BMW oil interval is just a way for BMW to save money when the cars are under the "free maintenance" period when new.

In reply to 02Pilot :

It got annual changes, never more than 10K miles.

JBasham said:

In reply to 02Pilot :

It got annual changes, never more than 10K miles.

Yipe. A3/B4 or LL-01 synthetic? Factory filters? 10k is longer than I would go, but unless it was combined with a lot of short trips (especially with an automatic), it shouldn't be disastrous at any reasonable mileage. BMW's CCV setups haven't been great, so moisture build-up can be an issue if the car isn't driven hard from time to time.

Recently replaced my starter in my E61 w/ the N52 and it wasn't all that bad, tbh. Even found a cheap starter on Amazon for $70 that works great.

BMW oil from the dealer, dealer filters or Mann filters.  Lots of short trips.  Might make one trip a month over 12 miles.  Both are two-pedal cars.  A man can only ask so much of a motor . . . .  

Short trips are killers, especially if the CCV gets clogged with oil-water emulsion. I would drop the interval to once every six months and go for a nice hour-long spirited drive every now and again. I try to make sure I bring my cars up to the redline at least once on any drive long enough to get everything up to temperature.

Yep, helps with the carbon buildup in these direct-injection motors too.

With the direct injection motors, they really benefit from a good Italian tune-up every once in a while.

Vanos solenoids you can't really check, but they're easy to pull and clean, the only thing you have to remove is the intake snorkel.  I eventually just started cleaning them during every oil change, it's only 10 extra minutes.

For the HVAC blower, it depends what breaks.  If it squeals, you can get a new squirrel cage cheap and swap the electronic controls.  You can totally unbolt and remove it without disassembling the dash in the slightest.  E90post has directions, and it's a little weird, but even with fiddling with it, I think I was done in 30 minutes.  If it's the electronic bits, that's a bit more expensive, but in my experience in the frozen north, the spindle rusts and it squeals. 

One other thing that is known to go on these cars is bushings, especially control arm bushings. But there's nothing special about them to replace them (other than the factory replacements are undersized).