From digest.v9.n730 Sun Dec 20 23:32:36 1998
From: Pearson-Franks Family <pearsonf_at_halcyon.com>
Date: Sun, 20 Dec 1998 21:57:30 -0700
Subject: <E28> Purchase/Maintenance Observations, Part 1 of 3
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, Stock, Tangen and of course, Welty,
without whom this would all be impossible. Or at least harder!
I included wildly personal prices where I could, 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:
- Head, cam & engine
- Cooling system
- Oil (& oil leaks!)
- Other engine compartment stuff
- Tranny and clutch
- Suspension, steering and brakes
- Interior, Electrical
- General (catch-all)
- 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_
(refer to definition above). There is a new variety with a
thread-locking feature, distinguished by a circle on the top.
(somebody might drop me the correct part number - I thought
I had it, but my local dealer sneezed on hearing it).
- 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.
- 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.!
- 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
- 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.
- 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. But hey,
you probably had your hands in your pockets and NOT a thermometer!
- 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. Easy fixes, write for details. $25 for kit
which replaces innards.
End-o-part-1. Larry F.
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