[MysticRob]

Posting just as an FYI in case anyone on the etherwebz has similar problems, concerns, questions, experiences, etc.

Been looking at E90s for years, but only recently got serious. Figured purchase prices and mod prices make this an easier decision now. Bought a 2009 Alpine White sedan with the Red-Brown leather interior. Love the color combo.

Car has 134k and was for sale on a used dealer lot specializing in German hardware. I have a lot of experience with used car maintenance (Dad was a 40-something-year GM veteran mechanic and taught me well) so I was looking for something cosmetically good but mechanically needing. All 6 cylinders had 150-160 PSI so figured I had a decent short block to work with. Anything to get the price down and be able to dive into my own maintenance and mods.

The used dealer knew what it had and priced it accordingly, so I got the car very fairly priced for what I've seen in the area. First thing I noticed was some slight hesitation and stumbling at idle during the test drive. No codes, just a bit off and down on power compared to some I've driven.

Decided to start with plugs, which hadn't been done in 20k miles according to CarFax. Original plugs were a bit oily, but no gas smells, and no other oddities. Swapped 'em out for Bosch stockers. Left them at stock gap. Bought these:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Then moved onto coils since I was planning to up the boost with a canned MHD tune, and what the car had seemed to date back to coils from 2006-to-early-2009. Bought the newest ones from OEM Bimmer Parts and installed:
https://www.oembimmerparts.com/BMW-3...8657273kit.htm

Next up was walnut blasting. I had a 2hp 8 gallon air compressor and shop vacuum already, so ordered the vacuum adapter and wand here:
http://www.bimmerhelp.info/Buy_Blasting_Tools.html

I got lucky and scored the Harbor Freight walnuts and media blasting kit from a guy on CL for 1/3rd the normal price. Intake valves looked horrible. Dealership records didn't show it having ever been blasted. There was also some oil coating the intake, charge pipe, diverter valve piping, intercooler, etc. Got that all cleaned, put back together, then ordered the Rob Beck PCV valve from BMS and their dual cone intakes. Install of those parts was quick and painless. Cleaned the VANOS solenoids at this point too, though they already looked good. Figured this is all-too-typical of a higher mileage N54 335i. No worries.

One of the reasons I got such a good deal was because of a nice hole in the lower grill and a decent sized dent in the intercooler. I took it out to inspect closer and discovered not only a small crack in the intercooler, but also a wheel weight that fell out and perfectly matched the dent. Easy to piece together what happened there. Bought a new lower grill, and also a Mishimoto intercooler due to ease of install (stock connectors), good IAT results, and great 30% discount from my son who knows a guy.

All this being done I still noticed some peaky boost and odd transmission shifting during acceleration and coasting. Played with the linear throttle mapping, which I liked a lot more than the stock throttle mapping, but it still had some slight shift hesitation and hard shift issues during hard acceleration. Figured I should change the transmission fluid to see if it helped, since again the dealership records never showed it ever being done.

Holy hell, so glad I did this today. The old fluid came out completely black. I was unable to see thru it in the least. Looked like gloss black paint coming out. I bought this kit from CTSC, and of course the original and new fluid is clear and yellowish monkeypiss-smelling stuff, not at all like the crud I drained out:
http://www.thectsc.com/products/oil-...ai-187-61.html
I replaced the worst pan bolts with the replacements, then pumped almost all 6 quarts of ZF Lifeguard 6 fluid back in after idling, shifting thru the gears and monitoring trans temp via the MHD app before I buttoned it all up.

Then I took it for a spirited drive. Wow, much improved shifting! Smoother shifts, less peaky boost and smoother acceleration with less hard shifting than before on linear throttle, and altogether an even better driving experience than ever before. At this point I'm driving a brand new 134k mile 335i.

Anyway, that's where I'm at. Love driving this car. Love working on it to make it even better than it was new. Next up might be an LSD and catted DPs and exhaust (once I can afford it). If anyone has any questions please let me know. I love working on new stuff and passing that info along.

[NoQuarter]

Awesome. Sounds like you hit all the important stuff.

How is on leaks? No oil filter housing , valve cover or oil pan leaks?

Don't forget the serpentine belt!

Cheers

[Jklad]

Vacuumed lines!!

[MysticRob]

Originally Posted by NoQuarter

Awesome. Sounds like you hit all the important stuff.

How is on leaks? No oil filter housing , valve cover or oil pan leaks?

Don't forget the serpentine belt!

Cheers

While the car was at the shop getting the compression tests done I also had them put it in the air so I could inspect the trays, engine, transmission, differential, etc, as well as the chassis for accident damage.

Amazingly clean underneath, and the serpentine belt looked brand new. Same with the tires. Not one cut, fray, or crack. No goopy oil & coolant mixtures either, but if the housing needs done at some point I'll do it myself.

Next up is putting the trays back on, then eventually when the weather gets better (rainy and cold in the bay area these last couple months) I'll paint the stock Style 287 wheels gloss black to match the door trim and new gloss black kidney grills I bought off ebay recently. I like the stormtrooper look and the stock anthracite color now on the wheels doesn't look good on a white car.

I should note too that the plastic allen head drain plug on the transmission pan was stripped out when I went to loosen it. Looked like someone had gotten under there to change the fluid at some point and gave up right there. I just loosened the rear pan bolts more than the others and let the fluid pour out the back till I could get the entire pan down without making too big a mess.

[MysticRob]

Originally Posted by Jklad

Vacuumed lines!!

Checked them all out too. 99% were tight connections, lengths all looked good, and all were flexible, not brittle. Only one suspect was the braided line that joins the diverter valves to the intake right where it connects to the intake. That one was cracked just a bit so I just snipped off the bad end to more pliable hose and put it back on.

My guess is everything looked so good with that high mileage because the car was driven ~17k a year mostly on the highway, judging by where the previous owner registered and maintained it in Roseville, outside of Sacramento.

I should add here that the fill plug on the driver side rear of the transmission was a bitch to loosen. Usually I just use a closed end wrench over the allen wrench (aka hex key) for more leverage, but being near the ground (ramps in front, jacks in rear) meant a lack of leverage options, and allen keys make for lack of adjustability due to their 60 degree insertion differences. Luckily the allen wrench pointed vertically toward the floor when inserted into the plug I was able to hit it once with a hammer to loosen it.

Also, due to my crappy leaky transfer pump I lost about a half quart of new fluid on the floor, but after cycling through the gears and ensuring temp was at 120* (love that MHD app!!) it ended up taking ~5.5 quarts total. Glad they included 6 in the kit!

[limitdown]

This is a great thread for guys buying an older high mileage N54. Looks like you did your homework on this platform well before you bought the car. It's awesome that you can do your own work.

The "lifetime transmission fluid" line that BMW gives is utter BS. It's for planned obsolescence. They want your transmission to break so that they can sell you another car. Essentially it's for the life of your warranty. After that, all hell will break loose.

Other problem areas for older 335i/N54's are Injectors, HPFP, LPFP, boost connections, vacuum lines, boost solenoid and (gulp) turbos.

I've had the misfortune of having some of the less common problems. Drive shaft chipped/dented, differential grinding, fried footwell module

[MysticRob]

Originally Posted by limitdown

This is a great thread for guys buying an older high mileage N54. Looks like you did your homework on this platform well before you bought the car. It's awesome that you can do your own work.

The "lifetime transmission fluid" line that BMW gives is utter BS. It's for planned obsolescence. They want your transmission to break so that they can sell you another car. Essentially it's for the life of your warranty. After that, all hell will break loose.

Other problem areas for older 335i/N54's are Injectors, HPFP, LPFP, boost connections, vacuum lines, boost solenoid and (gulp) turbos.

I've had the misfortune of having some of the less common problems. Drive shaft chipped/dented, differential grinding, fried footwell module

Yeah, it's odd how many things are relatively common problem areas, especially when compared to other makes and models. That said, I'll take the bad with the good, because the good comes at such a low cost entry point these days. What really sells it for me is how solid these cars feel with over 100k miles on them. The interiors are especially well built since they wear well (besides the steering wheel cover and power window switches) and don't make a lot of rattling noises. My 2013 C-Max sounds like things are going to fly off and start bouncing around the cabin like satellite debris.