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Long term diesel reliability

Discussion in 'Diesel' started by tek4tex, May 23, 2011.

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    tek4tex

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    I would love to hear from those who had rolled up high miles on the new twin turbo diesels. How has reliability been on the higher mileage cars? Has there been any fuel system problems?
    • Member

    floydarogers

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    There have been a few people with over 50K miles, a couple with probably 100K miles. I have 28K and most people have similar #s. No news is good news in this case.

    I peruse a couple other forums; no-one seems to be having particular problems. The fuel system seems bullet-proof at this point, with only some injector adaptation problems.

    The biggest problems seem centered around the DEF and it's injection system. Some crystallization that requires either emptying and cleaning the tank or new injector.

    It *is* a BMW and most other complaints wrt E90 apply.

    cwbiii guest

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    similar experience...

    I have similar mileage @28k and just had the crystallization problem. I also had a problem with what appeared to be an oil leak and was the inlet hose to the inter-cooler being loose and ballooned. Also had an electronic component replaced because the HD radio did not work correctly, it wasn't the radio but another computer somewhere was not doing its job. Everything covered under warranty as expected. The motor/turbo setup so far appears bullet proof. My average mileage is 30.9 mpg for the last 7.5k miles. ( I bought it with 21.5K on the odometer)

    Chuck
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    MAXROADSTER Ever chasing the elusive road runner!

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    Leased a 2012 X5 35D for business and put a lot of local miles on it as well as some long distance runs. We were driving back from Los Angeles to Albuquerque and was really impressed with the mileage, indicator said 27mpg! There was still a little more then 1/8th of tank when I pulled into the garage with the odometer indicating we had driven some 638 miles on the last tank of diesel. Next morning I got up to go to work and while the engine would turn over it would not start. Called my favorite BMW Technician, Tony. Tony walked me through a couple of solutions but none worked. Tony apologized and said he would send their Tow Truck out right away. Thirty minutes later I had a "loaner" as well. Two days later Tony called back and said he had found my problem, no fuel - the tank was completely empty? He said yes, the on board fuel indicator registered plenty of fuel but the tank was empty. BMW replaced the fuel monitoring system and put 5 gallons of diesel in it and the X5 ran fine! I have since reinstituted my old driving dictum of looking for fuel and filling the tank when I get down to an indication of 1/4!!! I now have 15,000 miles on my second diesel and continue to be impressed by this machine's form and function.undefined
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    floydarogers

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    An update at 117K miles. The only problems we have encountered with regularity are:
    1) Harmonic balancer (crankshaft pulley)
    2) CBU - but it's relatively inexpensive (for BMW) at $1200 or less.
    3) Oil supply lines to the turbos - a couple of them are really hard to access.
    4) 4D16 SCR Insufficiency - By far the worst/most expensive. See below (from a couple posts on e90post\diesel, so they also address some other stuff.)
    ----------------------------------------
    I was just reviewing my 335d maintenance log. Here's the timing/mileage.

    1) The EGR/SCR/DDE update recall was done in 3/23/2012 at 48K miles: replaced the Mixer and Metering valve. The had to replace the Metering valve again about 11K miles later because it failed. Not sure if that replacement was under parts warranty or the WA State California Emissions warranty.
    2) I had another CEL at 60K/61K, don't have code noted but probably 4d16/20ee, they replaced the Mixer (again, not sure which warranty covered it.)
    3) Again at 74K, they said that the Mixer had been put in backwards... No charge... Came back on but I refused further work, AND IT WENT OFF until:
    4) At around 89K/94K it came on a couple times; again reset and it went away, until:
    5) Beginning at 106K when the NOx sensors were replaced, and the thermostat replaced. And of course at 115K the DEF tank was replaced.

    Conclusion: you can ignore 4d16/20ee for quite some time (as long as you're prepared to reset the CEL occasionally and wait for a "hard fail".
    I totally understand (but don't totally approve) of the reasons to rip the emissions stuff out: I've spent around $7K on the NOx reduction stuff.

    BMW needs to actually fix their system, it's far too expensive. No wonder VW decided to cheat.
    -------------------------
    Maybe I should author a post about this whole 4d16 issue - it's actually several separate issues that each result in a CEL with that as the final code. There have many posts here, and on the bimmerfest diesel forum, that cover this issue, but in a piecemeal fashion.

    The fact that there are at least 5 separate components that can fail and result in a 4d16 complicates the diagnosis of the root cause, and solution.

    1) The SCR Metering Valve (some people call it an injector; it sits at the bottom of the DPF) gets clogged or fails.
    2) Bad DEF fluid.
    2b) At some point, the DEF Mixer is also checked. This is an insert just upstream from the SCR Catalyst that adds turbulence/mixing to the DEF and exhaust stream. It can get corroded; about the only cheap part in the system.
    3) One of the NOx sensors fails or runs out of lifetime. Exhaust gas sensors (O2 and NOx) have a finite lifetime - the NOx sensors will last only 80K-120K as far as I have seen. They're quite expensive - $400-$500 each.
    4) Thermostat is also checked. Low operating temps can affect the SCR Catalyst (and also DPF regens.)
    5) SCR Catalyst. Costs $1460 (price from realoem.com). Haven't seen that they fail very early.
    6) DEF Container (SCR tank). There are so many reasons for this to fail - the temperature sensor, transfer pump, injector pump, heating element, etc. And BMW won't sell individual components or rebuilt tanks.

    The above is pretty much the order in which BMW techs follow the fault tree to diagnose problems. Which means that the NOx sensors might be good (or at least marginal) and get replaced even though it's the SCR Catalyst or the DEF tank. At least some components in the DEF Container report faults, which can then be tracked down outside the above fault tree.

    So, my 335d at 117K miles just had it's DEF container replaced - cost was $3200 at an independent (BMW Bellevue was $500 more expensive - all due to labor rates.) The active tank level sensor failed. I kept the tank and intend to rebuild it myself. The level sensor is a component that is available from VW - there's been a couple threads about that). There is also an easy fix for the thermocouple/temp sensor.

    About 10K ago, I was getting 4d16 faults and they ran the fault tree and replaced the NOx sensors. $1800 or so. That fixed that problem, which actually started around 94K miles and gave intermittent faults, which I reset a few times with my BavTechnic tool until it became non-intermittent.

    I'm living [IMG] for the day I get another one, as it will be the SCR Catalyst.

    Here are several related threads, including a couple on replacing DEF Container parts.
    http://www.bimmerfest.com/forums/sho...d.php?t=756934
    http://xemodex.ca/ca/product/scr-con...eturn-for-bmw/
    http://www.e90post.com/forums/showth...2#post20485362
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    MGarrison

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    Floyd, thanks for the update!
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    • Technical Service Advisor

    charlson89

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    If it wasn't for the emission system on the diesels they would be the best cars BMW makes.
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    DASchempp

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    I thinking of buying a 2014 X5 xdrive 35d. Is this a mistake? Mileage is 24K and the SAV is a certified pre-owned from a BMW dealer.
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    lhazel '13 F12

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    DA, I bought a '13 X-5 3.5d new in 7/13. Now has 46,200 miles. Used to commute 99 mi each way, 3x per week. Retired now. Mine consistantly averaged 21.8 mpg at an avg speed of 65 mph (read 80-85 mph for 80 miles on the Fla Turnpike and 35-50 on local roads. Thank you very, very much, Mr. Valentine!). 2014 and newer X-5 diesels get better mileage, I'm told.

    This has been the most reliable vehicle I've owned. One reprogramming of the computer required shortly after purchase, and last month a small oil leak was noticed on the garage floor, which was caused by a cracked oil supply line to a turbo. Repaired under warranty.

    If you drive a lot, I'd recommend going for the CPO vehicle you're looking at. If I were still doing regular high-milage driving, I'd definitely be looking at a late-model used X-5 d. If I keep the vehicle post warranty, I will definitely buy an extended warranty. As my Service Advisor recently said, "BMWs are tough cars to own out of warranty". My friends say the same thing about their Mercedes, Porsches and Jags.

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