| scottie | This originally appeared on the e28 board, but it has signifigance also so e23 purchasers....happy hunting!
From: Pearson-Franks Family <pearsonf@pop.halcyon.com>
Subject: E28 Purchase/Maintenance Observations
Fellow Digesters:
It has been a while since I have shared this, and I have
been updating as experiences dictate, soooo
The following notes are a collection of observations and experiences with my fav Bimmers: older 5ers. My observations are just that, not necessarily the Truth (capital 'T'), but _my_ experiences and judgements, leavened with mucho experience from other Digesters. My thanks to Mssrs Anderson, Boylan, D'G, Eilenberger, Levinson, Lin, Lyle, Stock, Tangen.
I randomly include wildly personal prices, for ballpark info and potential purchase price negotiation. I look at them from the point of view of the DIYer, parts plus shop time (if required).
Comments, corrections, additions all welcome. With any luck
at all, this will be useful to others who enjoy these cars as much as I do!
I grouped the the classic E28 look-for's:
1) Head, cam & engine
2) Cooling system
3) Oil (& oil leaks!)
4) Other engine compartment stuff
5) Tranny and clutch
6) Driveline
7) Suspension, steering and brakes
8) Interior, Electrical
9) General (catch-all)
1) Head Gasket and other Engine Notes:
- Top end work a frequent 100,000ish requirement. $1500+ for
parts (do all belts and hoses, too!) and shop time.
- Compression or leak-down test very informative, look for
160+ on all cylinders, +/- 5 OK, +/- 10 marginal. If you
want details on my many recorded numbers, or a rap on the
leakdown test, drop me a note.
- If you pull the valve cover (which I would recommend) check
that the two 12mm head 'banjo bolts' that secure the oil
bar to the head are snug. If these are loose this is _bad_.
There is a new variety with a thread-locking feature,
distinguished by a circle on the top; pn 07 11 9 917 511.
Ought to replace both crush washers as well, pn 11 42 1 252 343
(you will need 4 - duh! <g>).
- Check the cam rubbing surfaces: the peaks of the cam lobes
should have no discernable wear (using the patented fingernail
technique) and the rubbing blocks on the underside of the
rocker arms should all appear the same in profile. If the
banjo bolts were loose, TAKE YOUR TIME doing this part!
If replacing the cam, add $300 to head job.
- Easy things to look for in this department: coolant. If
someone is concealing a known head gasket problem, the coolant
may be clear and/or rusty, meaning they consume a lot, and have
been just adding water, or the coolant may be suspiciously
clean, meaning added to all the time.
- Spark plug condition. In addition to the normal interpretation
found in every Haynes manual (the color picture page), look for
differences in plug color. Cylinders leaking coolant will have
_very_ clean plugs. Pressure washed, if you will.
- If you are pulling the plugs, run a thread-chaser - just like a
tap only it is driven with your spark plug wrench. This will
clean the carbon, etc. out of the threads; making it oh-so-much
easier to run in the new plugs. You _are_ using anti-seize on
the plug threads, aren't you?!?
- Coolant burners (cracked head or bad head gasket) will put out
reams of white smoke (actually steam) when they are first
warming up. Smells kinda sweet, not unlike coolant.
- Coolant system pressure and leak-down useful, but not definitive
for head leak problems. Cracks, or high porousity areas may
not show up with a static pressure test.
- If you are looking at an 'e' motor and do not have conclusive
proof that the timing belt has been replaced in the last 5 years
or 50,000 miles, just do it. Better than bent valves, etc.!
- The ECU cares a lot about what temp the coolant is. Or,
thinks it is. If the sensor or wiring to it is bad, the
ECU thinks it is 0 degrees F or something, makes the
mixture rich as heck, which causes black smoke in the exhaust,
bucking, hard starting and then no start. If you are in
the no-start mode, pull a plug and see if it isn't soaked
with gas. If so, drop in a new set and it will start right
up, but run rough, prolly with aforesaid black smoke. Check
the sensor, a single-wire white thingie in the thermostat
housing. The crimp on the terminal itself dies, the wire
can be broken inside the insulation (tricky!), but you can
test for that by pulling on the terminal. The sensor itself
measures something like 1-2K ohms at room temp.
- I happen to believe in retorqueing the head bolts on occasion.
Beliefs and experiences vary here. If interesting in
pursuing, drop me a line.
2) Cooling System
- It's my experience that radiators are a 8 - 10 year
consumeable. The E12's have brass cores and tanks and can be
rodded out. The E28's have aluminum cores with plastic tanks
clipped to them with one-time-use crimps. And, the plastic ages
badly, leading to broken hose connections, etc. Not worth
repairing IMHO, but some Digesters have had good luck with
Reseda Radiator.
- Normal water pump inspection: check the water pump by rocking
the fan, both in line and 90 degrees from the pressure of the
belts. Play should be small, and the same in each direction.
$45 part, add $200 for all belts and hoses.
- When replacing the water pump, replace all the 6mm (10mm head)
cap screws. _And_, run a 6mm tap into each hole. This can
save mucho grief with holes filled with gunk, that cause the
cap screw to bottom out and either leak or shear off :(.
- From underneath with a light, find the 'weep-hole' just aft
of the fan clutch mount. Should have no 'tear-tracks'
left from a bad bearing seal.
- Belts and hoses should be uncracked and not bulgy, respectively.
- Temp guage should run at 10:30 to 12 o'clock under any and
all conditions. After a test drive, leave it idling for 15
minutes or so and see what it goes up to and settles at.
Anything over 12 o'clock means maintenance coming up.
Radiator likely, typical consumable. $240 part.
- If suspicious of guage/sensor inaccuracy, wrap your hand around
the upper radiator hose: if you can squeeze it for an
indefinite amount of time, <50 C, not warmed up yet. Hold
several seconds, 70 - 90 C, OK. Can't hold 1 second, >90 C,
which means trouble. Or, use a candy thermometer. Find one
of the depressions in the thermostat housing, fill with a
bit of water (to conduct heat) and stick the thermometer in it.
It will read within a degree or two of a good thermostat spec.
- Check fan clutch. Should not freewheel when spun, but have a
certain resistance. Should give more resistance at temp, but
this is hard to 'feel', in my experience. $30ish.
- Heater control solenoid fails, resulting in erratic heat, or
heat all the time. $25 for kit which replaces innards. The
three thermistors that regulate temp also fail. Easy fixes,
write for details.
3) Oil and Oil Leaks
- Visually, 'fresh' oil will appear a clear brown, as you know.
Black just means old, any cloudy or white means water, which
is very BAD, 'bad' being likened to crossing two anti-proton
streams, resulting in the destruction of the universe as we know it.
- Check under oil filler cap: there should be no cloudiness, and
gives you an idea of internal cleanliness (which is good).
- The owner's manual says it is 'OK' if the oil pressure light
comes on 'at times', like idling when hot, but should go out
when revved. Drives me crazy if it comes on at all! If the
oil light comes on like this, replace it. If it _still_ comes
on, replace the oil pump - see below.
- The oil pressure sender is a frequent leaker. The leak will
track down the side of the engine and drip off the lowest
point of the bell housing, so don't confuse it with other
potential problems.
- The pan gaskets occasionally 'creep' out of their space and
self-destruct. If you go in to replace this on a high miles
motor you intend to keep, replace the oil pump (and probably
the sprocket) at the same time. $150ish, and well worth it.
4) Other Engine Compartment Stuff
- All fuel lines are suspect by 100K - especially the short hank
to the cold start injector at the lowest extreme of the
intake manifold, for some esoteric reason. Don't use cheap
stuff! Buy the BMW 8 x 13 mm original from one of many sources.
- Vacuum leaks are a major hassle. Prime symptom is rough idle,
flat spots at mid revs, may also be fuel pressure regulator.
Do easy candidates first: put an o-ring in one of the grooves
in the dipstick top. Put clamps on the hoses to the valve
cover and idle motor (if E28). Replace any hard-as-rock
hoses in general. Replace the fuel injector o-rings.
- Look at the brake fluid. Black is _bad_, but at least means
it wasn't being topped up each week (see 'slave' discussion
below). Color of the brake fluid is a very good indicator
of the general tenor of the maintenance regime for the car.
If it is black as pitch, indicating it is _not_ getting the
yearly replacement the anal-among-us so lovingly do, check
more closely for all the other maintenance opportunities.
- Lots of things can make this baby idle rough; already
mentioned vacuum leaks. Mucho covered in FAQ's. Best I
have seen is by Sam Lin <Sam@cmdexsvr.cmd.com> for a copy.
- Plug wires are a 100k consumeable in my book. Cleap insurance,
can help several marginal symptoms, lotsa sources, $80ish.
5) Tranny and Clutch
- The 4-speed auto is famous for scorching the first clutch
pack if revved in neutral. Actually not a terrible job
to accomplish if you are a steely-eyed DIYer. Check that
you can get the parts locally first!
- The Getrag 5-speed should enter all gears smoothly -
they are not especially prone to synchro failure in normal
operation (i.e. not auto-x'd) but most are 'notchy', kinda
hard to push into gear, especially when rev's not synched,
but easily improved by putting in Redline MTL tranny oil.
- Every 100K+ Getrag I've seen leaks. From the rear is OK
but messy - shift shaft seal fails, soaking back of tranny.
Output shaft seal weeps, no major heartache. Seam between
front and rear half of tranny case weeps, wets bottom of
tranny, but no sweat. Saving the best for last: If there
is oil (not brake fluid, see below) coming out of the drain
hole in the bell housing, either the tranny front seal is
leaking, (likely) or the engine rear main (possibly). This
is _bad_ (see definition above) because the clutch is not
designed to be oil-bathed, and will tend to chatter and fail.
Seals are $5-$10 each, clutch trio (pressure plate, clutch
disk, throw-out bearing) are $300ish. All quite doable, but
considerable labor, dropping exhaust, removing driveline.
- While you're down there, check that the rear tranny mounts
have not gone to mush, they do that. Check the engine mounts
too; check for cracks in the top, especially on the right.
- Clutch pedal should depress smoothly, although with a lot more
force in the 535i than the 528e or a 3-series. Should not
hang up on either the upswing or downswing - that could be
broken 'ears' on the throwout bearing.
- Stick your fingers under the forward edge of the dash sound
cover just above the brake pedal and feel for wet, and smell
your fingers - odor of brake fluid means the master is leaking.
- Also check for clutch master cylinder flex to one side when
the pedal is depressed - the pedal bracket mounting the
master cylinder fatigues and cracks, allowing the master to
move around. Time-consuming to replace, but not hard.
- If brake fluid is leaking out of the drain hole of the bell
housing, the clutch slave cylinder is leaking - very common,
but cheap and easy to fix. Smell it to distinguish from oil,
but bear in mind that you could be getting both. Another
tip-off for this one is really clean brake fluid, from someone
topping it up as it coats their garage floor. Another
symptom for the slave being bad is that the clutch disengages
very close to the floor, or the pedal will not return.
This symptom is temp sensitive - may be fine when all is warm.
Clutch pedal return problems _may_ be the assist spring
on later E28's, if you are lucky ;~).
- Many of these beasties have developed a lot of play in the
shift mechanism: worn shifter bushings, mushy rubber mounts
on the shift pivot mounting plate. I greatly enjoy the
result of the Metric Mechanic short-shift kit. Stock shifter
bushing parts will cost you $35-$60 at a dealer, MM shifter
$200, ACS shifter $800. Or BL/SS. No affiliation.
6) Driveline
- Check guibo, the rubber flexdisk connecting the output of the
tranny to the driveline. At 100K it will be cracked, and may be
the cause of a shudder at certain speeds (frequently 25 to 35
mph), especially while under load.
- Ditto the center bearing and support, but much harder to check,
as you have to dispose of the exhaust system (well, remove
enough to get the heat shield off, but you know what I mean!).
- Do the traditional twist-drive-components-and-note-any-play
of the two U-joints. The rear one is the more likely to fail,
and is easily observed. Bear in mind that if they are bad,
you will need to get the driveline rebuilt, $450ish if you
rebuild the whole thing (recommended). Check the Roundel for
rebuilders - I have used Portland with great success.
- Lots of candidates for driveline shudder; such as motor mounts,
rear subframe mounts, and rotating the driveline to diff.
orientation (which might have been thrown off by previous work).
- Drop me a note if you want the long diatribe on dropping the
exhaust, removing the driveline, etc. Almost the same for E30's.
7) Suspension, Steering and Brakes
- There are books written on the subject of the front control
arms bushings, but the exec summary is: they all die. Symptoms
of impending doom are shuddering when braking, especially from
say 65 down to 45. May get very jumpy at the steering wheel.
There are upper and lower control arm bushings and ball joints,
and lots of alternatives (bushing upgrades, etc.). FAQ's
abound. $160-$800 in parts. Go with the modified 750 ones
(Steve D'G or BavAuto) if you plan on keeping the car.
- And, of course, the front rotors warp. $120ish. Always replace
the 5mm hex that secures the rotors. Cheap insurance.
- The 535i boost system feels weird (the 528e is a very vanilla
vacuum boost.) The point is; in a perfectly healthy hydralic-
boosted system, you can 'surprise' the system if the engine is
running but the car is standing still by stomping the brake
pedal hard - you can make it most of the way to the floor. Not
to worry; you are _way_ past the point that triggers ABS, but
tech checks for track days may be tricky - the typical M3 driver
doing the check will panic. Explain ahead of time!
- With the engine running for brake boost, stand on the brake
pedal for 30 seconds or so. If it drifts toward the floor,
time for a master cylinder. Replace, don't rebuild. $80
to $180, +/- year and/or ABS.
- Steering should be 'tight' when gently rocked at the center
of travel when the engine is off. 'Clunks' may mean Pitman
arm bushings (_bad_), loose collar nut under dash (easy) or
bad center track rod (cheap, <$60, but obnoxious). Play
also comes from a worn idler arm bushing. <$30ish>
- The two senders on the brake pressure regulator regularly leak.
Replace them both, $32ish total.
- There is a 'nitrogen ball', frequently referred to as the
'brake bomb', due to it's cartoon-bomblike appearance, that
dies. Symptom is a slow-to-respond brake pedal, frequently
accompanied by a flash of the 'brake' idiot light, and/or no
brake boost immediately after shutting down the engine. (It
should give several-to-many 'assists' after shutdown). Again,
several fine FAQ's on replacement (somewhere). $60ish.
- When checking the p/s and brake boost fluid level, bear in
mind that if the engine has been running and the nitrogen ball
is in working order, there is a inch or so of fluid in the ball.
Fully discharge the ball by stomping the brake pedal 10-20 times
and watch the fluid level creep up. Adjust to the line in the
side of the can at that point. This applies to the 'i' only;
as the 'e' uses vacuum boost.
- Fluid should be pretty; not black. There is a filter in the
bottom of the reserviour that should be changed on the 'i'.
- This is another classic oil leak source: the cheapy crimped
hose clamps on the lines to the reserviour 'relax'. Replace
with decent stainless steel from Steve D'G. Replace the
low pressure hoses with quality stuff if anal-like-me.
8) Interior, Electrical
- Alternator brushes ($5.50 at BavAuto) are typical 140K items.
Two screws pop the assy off the back of the alternator to check.
- Weird guage problems (tach or mpg guage erratic, etc.) indicate
a possible SI battery replacement needed. Very typical, and
lots written on the subject.
- Dead SI batteries may also cause the Oil Service lights to be
on at odd times. <$10 for batts, couple hundred for rebuilt board.>
- If batt's are OK, lights are very easily reset, refer to FAQ's
and/or reset tools, or, for the very brave, just ground pin 7
of the diagnostic connector, turn on the ignition (but don't start)
until all the lights go off, and you're done. Many will tell you
this procedure is highly risky, but so is cutting vegetables
with a dull knife - sheesh! no rocket science here.
- Jump pins 11 to 14 for remote start. (15 pin version)
- Headrest up/down dies. Easy fix, good FAQ's elsewhere. $0.
- Just an observation: window lift and sunroof switches were
illuminated 'standard' in late '86 US cars on. Easy swap,
wires already in place, as an easy upgrade. I got a set from
Jason at Zionsville, very cool outfit (no affiliation, yada x 3)
Also, they get mechanically sticky and electrically erratic if
exposed to Armorall. Switches can be opened and cleaned.
- Fuse box has chronic, but easy problems. Fuse clips corrode,
wirebrush 'em. Fuses corrode, replace 'em all. Connections inside
the box can get erratic or hot. A real bear to troubleshoot.
- Several chronic problems show up as 'cutting out' at any speed,
frequently the 'main' relay, sometimes the fuel pump relay,
sometimes the position or timing sensors. Connections to the
_underside_ of Fuse 6 can corrode and heat up.
- Several handy voltages to know, measured at the battery:
10.0v - voltage at batt while cranking starter
12.3v - 50% charged battery, 'at rest'
12.7v - fully charged battery, 'at rest'
13.6v - minimum acceptable alternator output at idle
14.3v - maximum acceptable alternator output at revs
Ref: Mark Calabrese article "In the Dark?"
March, 1996 Roundel
- If the ABS light comes on after you start rolling, chances
are one of the sensors is faulty. The wires flex and fail
inside the insulation. Definitive test is with an ohmmeter
on the connector to the ABS brain above the fuel injection
ECU above the glovebox. Details in Bentley and elsewhere.
Also, the sensors or the gear they read can just get scummed
up, and are recovered by mere cleaning. Which entails pulling
the wheels, rotors and sensors. <$0>.
9) General
- Don't believe a _dang_ thing a salesperson says, if there
is not documentation behind it. "Changed the oil every 3K
miles" if literally true means they _never_ changed the
filter. Semantics? Maybe. The car tells the real story,
a salesperson has a car to sell.
- Lots of exhaust replacement opinions, choose one you like.
The E28 cats crack, but can be successfully welded for years.
- Water in the trunk is usually a bad (hardened and/or cracked)
rubber gasket around the taillight assy's. Replace them both.
- Buy a Bentley manual, and an ETM (Electronic Troubleshooting
Manual) if you are electrically astute.
- Check to see if it has the TRX tires. If so, you face one of
the classic $$$ delimmas - discount asking price $400 if tires
OK, $1000 if tires need replacement. Many details elsewhere.
- For an excellent treatment of all the E- and M- numbers, check:
http://www.unixnerd.demon.co.uk/enumber.html, John Burns' page.
That's it! As before, comments, corrections welcome. Larry F.
- --
Pearson-Franks Family
Issaquah, Washington
Scottie Sharpe
Sysop
84 745i
85 535i |