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Thread: E31 m70 Problems

  1. #1
    Join Date
    Oct 2017
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    2000 EuroSport RHD 540it

    E31 m70 Problems

    I know that there are lifter taps that are present when the banjo bolts get a little loose, but other than that are there any more problems with the m70 engine as a whole? Looking into a '92 850 6 speed and want to make sure I don't start throwing money at a pit.

  2. #2
    Join Date
    Dec 2007
    Location
    orange, ca
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    2,507
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    '91 e31
    Best advice: Read, read, read on the forum here and get a good sense of what you'd be getting into with these cars. If you enjoy your own wrenching, they can be very rewarding. If not - very expensive to maintain. m70 is very under-stressed and reliable - the problems are everywhere else. If you don't know the cars well, paying for a ppi from someone who actually knows the e31 specifically is well worth the time and money. At the very least, you'll have a good idea of what things cost to make right. Although there are a few exceptions here (99% of whom do their own work and enjoy it), most consider the purchase price merely an admission fee and have spent double over the years for repairs and improvements.

  3. #3
    Join Date
    Jan 2005
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    Japan
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    54,654
    My Cars
    11/88 E32 750iL+98 E36M3
    by olinjohnston: INFO-> Buying an E31 - How to know if you're looking at a good one

    People often come on the board to ask "what to look for" when inspecting an 8-Series. As mysterious and alluring as they are, the E31 is still more or less a normal car, so everything you would check during a pre-purchase inspection on a regular BMW would still apply. That said, there are several areas of the E31 specifically, that are worth noting.

    Outside:

    1. Check the body for rust - particularly around the edge of the sunroof panel, along the bottom of the doors, and fenders.

    2. Inspect the operation of the door handles and trunk handle. The cheap metal inside the door handles often fatigues, making them inoperable or sticky to return. Also watch for worn door brakes that creak when used. A broken one will tear the mounts through the sheet metal inside the door.

    3. Make sure that all body panels align well, and that the hood opens and closes easily. Check alignment of the front nose piece, especially around the indicators on the sides. Note the condition of the front spoiler. These are sometimes cracked up beyond repair, and are expensive to replace.

    4. Inspect door and window weather stripping. Look for paint overspray on seals that might point to prior accident damage and lazy repaints.

    5. Do a thorough check of all the exterior lights. Things like non-working high beams are easy to overlook on an initial test, since pulling on the stalk without the headlights on illuminates only the lower FTP (flash to pass) lights without raising the pop-up assemblies. Make sure the taillights work, and are not affected by poor wiring connections in the trunk lid. The lenses are pricey.

    6. Look underneath the car for any obvious signs of damage or leaking fluids. See if the rubber jack pads are in place. These are often missing.

    7. Check so see that the tires are matching and have good (and even) tread depth. The E31 can blow through tires if suspension parts are worn out or out of whack. Learn to read manufacturing date codes if you don't already. The tires on stored stock E31 wheels can be over a decade old and still appear to be good. These are not always safe for normal use.

    Inside:

    1. Sit in both seats and test every function of their movement. Watch for twisting and listen for unpleasant groans. Fold them forward. The release latches often break. Test the lumbar support and seat heaters. Also test the mirror and steering wheel adjustment. Make sure the wheel raises when exiting.

    2. Inspect the leather and the carpeting. The upholstered items of the E31 are among the most expensive parts to replace, and some are no longer available from BMW. As a rule, remember that cosmetic items, especially E31-specific ones, are often much more expensive than mechanical parts. Don't settle for a rough-looking interior just because "the engine pulls strong." This is a typical newbie mistake. You could probably find the entire drivetrain for less than it would cost to make a crappy interior new again.

    3. The stock headliner on these cars, as nice as it is, cannot stay on the ceiling. The foam backing degrades, and it will fall down. I have seen a museum kept E31 with 36,000 miles still have a bubbling headliner - this is mainly an age issue. If replaced, 9 times out of 10, the previous owner will have taken it to a shop to have it redone with cheap material that doesn't match, jams the sunroof, or just plain looks cheap. A true quality job is very expensive and/or time consuming, so keep that in mind.

    4. On 93+ cars, check for worn out chrome seat belt feeders. The shiny plating looks great compared to the old waxy-looking black ones, but it can peel off, making for a scratching sound every time you pull it out. Plus, it frays the fibers of the seat belt. These are not replaceable without buying a whole new belt assembly.

    5. Test the interior lights, honk the horn, listen to the stereo, and turn on every feature you can. Bring a CD with you and test the 6-disc changer if you plan to use it. The "Disc Error" fault is quite common with the upright-mounted Pioneer unit.

    6. Roll down all the windows and see that they work well. Open and close the sunroof…a few times. Make sure it's level on the roof when shut, and that the inner cover retracts when opened. Operate the tilt function as well.

    7. Press the "CHECK" button on the MID. If you can barely read it, plan to spend around $150 getting the display repaired, or over $400 to replace it. It is very delicate, and home repairs do not make the pixels stay lit for long.

    Under the hood:

    1. Hopefully the car is cold (having not been started for the day) Listen for any unusual starting characteristics, or hints of discharged batteries. Let it idle and note any excessive vibration or exhaust smoke.

    2. Look at all the plastic covers and make sure they are in place. Check for broken tabs on the fuse box and missing fasteners along the front. Even though these things are cheap, they are indicators cut-corner maintenance if the owner wasn't willing to spend the extra few dollars.

    3. Inspect the intake(s) and make sure there are no obvious air breaches. BMWs hate air leaks. They will idle rough and throw fault codes if unmetered air is allowed into them.

    4. Check for oil leaks at the valve covers, and anywhere else that is visible. Check for coolant leaks at the radiator, coolant expansion tank, cap, water pump, and hoses. Pull the dipstick to check if the oil level was kept up. (If the seller cannot be bothered to top it off, even just for the sake of presentation, what else has he/she overlooked?)

    5. Check for decayed wiring, especially in the headlights if you are able to remove the covers. The alternator cable on V12 cars can be a weak spot as well.

    6. Check the coolant and brake fluid. Make sure that coolant is not contaminated or milky. Open the hydraulic fluid reservoir. If the fluid is reddish, it has probably been contaminated with ATF, and will need to be flushed if you plan for it to operate properly without leaking. The correct fluid for the power steering and brake assist circuit is Pentosin CHF 7.1 or CHF 11S, depending on the year. If the seller does not know about this, prepare to uncover more issues down the road.

    Test drive:

    1. Wiggle the steering wheel. Feel that slop in the middle? Don't underestimate it, or plan on it going away easily. The steering gearbox is finicky and most cars will not be able to have that slack "adjusted" out of them. Even after replacing every piece of steering and suspension linkage, you may still encounter a dead spot on center. Just be aware that this is something that E31 owners spend a lot of time and money chasing down.

    2. Feel for the well-known 55-60mph shimmy. This can be a great number of things ranging from cheap stuff like missing hub-centering rings, all the way to full-on suspension rebuilds. The most common culprits are the upper control arm bushings, but if the car was not kept up, it probably needs everything.

    3. Test the brakes in a safe area. Engage the ABS. Make sure they work consistently and predictably. Sometimes a failed accumulator sphere can show itself in the form of a scary delay during a panic stop. Although, you might not discover this until your life flashes before your eyes.

    4. Listen for squeaks of all kinds. The ones from the rear can be elusive. Some owners have reported that their squeaks were caused by failed shock tower mounts. Most are less serious.

    5. If there are any warning lights on the dash while driving, don't always assume it's something cheap. Low-end dealers and shady sellers love to say things like "It's just a sensor" but it often isn't. (Otherwise they would have fixed it before the sale)

    6. Pay attention to how the transmission shifts. It should not be jolting. The later 5-speed automatics have a "lifetime" fluid fill - meaning that when it fails due to negligence, that was its "lifetime." Ask the seller if/when the fluid and filter were changed. On the 4-speed and the 6-speed manual, there is no excuse for skipped maintenance.

    Sum up:

    These guidelines should be followed on top of any normal procedures for inspecting a used vehicle. This is based mainly on my experiences with my 840Ci.

    I personally believe that maintenance records speak volumes about a car's history. Plus they are just fun to refer to later. Whether or not they are available, plan to spend a decent sum of money bringing the car up to par. These cars are super old now, and even enthusiast owned examples will have a list of needs.

    As for what you "should pay," that is highly subjective. Each 8-Series model has a varying degree of rarity/desirability that plays a part, but ultimately overall condition is the most important factor. Also, don't assume automatically that a $5000 E31 is a "better deal" than a $15,000 one. Buying low and planning to fix it up is honorable, but it is often a false economy when the expenditure to make is as nice as the "overpriced" one can easily add up to more than the purchase price of the latter. Unfortunately, there really is no accurate "Blue Book" for the 8-Series.

    Happy hunting!
    Shogun tricks and tips for the E32 series are HERE!

  4. #4
    Join Date
    Oct 2017
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    2000 EuroSport RHD 540it
    I have been looking at these cars for a while now, but I just want to make absolutely positive that this is a known problem and has a known fix. I have a video of the tick. If anyone has had this problem before what is the cost to fix?
    Last edited by mateo8; 11-02-2017 at 11:12 AM.

  5. #5
    Join Date
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  6. #6
    Join Date
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    99 840ci Sport Indv
    Link below:

    https://youtu.be/oVTK0Kb23us

    ....sounds like a good one to me!
    Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i


    My BMW Repair YouTube Channel
    My Current 840ci Sport Individual
    My Current 650ci Sport Individual
    My E31 Repair and Information Website
    My E38 Repair and Information Website
    My E63/E64 Repair and Information Website

    Chase - Heroes to a generation

  7. #7
    Join Date
    Oct 2017
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    Thanks Timm, I really appreciate your website on the e31: http://www.meeknet.co.uk/E31/Index.htm I have poured over nearly everything on your website excellent read on anything and everything. Wish I could get the same purple you have on your 840

  8. #8
    Join Date
    Feb 2018
    Location
    Izmir turkey
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    3
    My Cars
    1991 850i
    I wish I had seen this before I bought my 850 , anyway it is mine now . Thanks for all the info.

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