Making my '92 325i reliable--summary

["Douglas M. Max" <DMax@xxxxxxxxx>]

Here's a summary of the responses I've received (some publicly; some
privately) to my prior query, copied below.  I don't know if this is
appropriate on this list or not, but I've received a couple of private
requests for the responses, so I thought I'd create a summary.

BTW, I've copied each response after an "*" and kept the author
anonymous (I didn't want to keep track of whether the responses were
public or private).

Doug

My question:

>I just celebrated 100K with my car and family and am wondering what I
>should replace to help it make the next 100K?
>
>In particular, those things that might go without warning and stop my
>car...fuel pump, alternator haven't been replaced, for instance.  Are
>they going to break within 20K anyway?
>
>Are there other things that fellow '92 owners know are going to go
wrong
>and catastrophically?  Give me the list, however long and expensive it
>is! And, if you're able to categorize the failure as catastrophic (like

>fuel pump) or a fixable nuisance (like alternator? I'm right that the
>car can drive and be jumped without an alternator working?).


*I had an alternator fail marginally- no dash light but the output
voltage was low, darn
near ruined my battery and could have stranded me. I installed a voltage
gauge to guard
against this in the future.



*Yours is a somewhat different animal than my '89, but for what it's
worth-

If yours has one fuel pump, located in the tank, I'd change it- the '89s
are
notoriously unreliable, I change mine every time I do the timing belt.
The
two pump systems (one in the tank, one under the car) are generally much
more
reliable.

The diode clamped relays that control the fuel pump and ECU are known to

fail, this is a nasty deal because they can fail and "heal" themselves.
Not
that expensive, again I change mine every time I do the belt, and carry
spares with me.

And, of course, don't forget the timing belt and fuel filter.

My E30 needed wheel bearings, rear subframe bushings and a radiator in
the
100-200K range, and I generally do the suspension every 100,00 or so
(control
arms, tie rod ends, shocks and struts).

Again- don't know how much of this applies to you, but it will give you
some
asking points.

*
What about the head studs?  They are a common point of failure and if
they haven't been taken care of, they probably should be.  Potentially
catastrophic failure.

We assume the timing belt has been changed at the required intervals.
If not, you better look after that.

Response from another poster:
Failing head studs wasn't a problem with the M50 engine, and it has a
timing
_chain_, not a timing belt.



*
BMW alternators are very reliable.  Just make sure that the vent tubing
is
intact, so the alternator receives sufficient air to stay cool.

If your alternator fails, you won't be able to charge your battery.  So,

unless it's a major internal short (to short out the battery and
discharge
it), you should be able to drive a short distance to get it repaired.

BMW fuel pumps are also very reliable, provided you don't run your tank
down
to 'fumes'.  It uses fuel as a lubricant, so if the tank gets too low,
and
it runs dry (when you turn a fast corner), it will eventually wear out
the
pump.

Here are some known failure items:

Water pump: Catastrophic! Once you hit 60k miles, you're riding on
borrowed
time.  Your car probably has a pump with a plastic impeller, and these
tend
to crack and disintegrate.  Replacements had metal impellers, but BMW
recently went to another type of plastic impeller.

Radiator: Catastrophic! The plastic gets brittle, and the upper hose
fitting
will snap off, resulting in major coolant loss.  With 100k miles, you're

driving on borrowed time.

Thermostat cover: plastic, gets brittle.  When you change water pump and

radiator, go ahead and replace the thermostat, and get an aluminum
cover.
They are available from aftermarket sources (BMP, others)

Rear Shock Mounts (RSM): these things deteriorate and end up causing
rear-end clunks.  If they break totally, the top of the shock will pop
up,
and possibly damage something.  Replace them with the RSMs for the E46;
they're a direct fit, much stronger, and cheap (less than $20 each)

Rear Control Arm Bushings: these wear out and cause the control arms to
move
in unnatural ways, making the rear of the car feel loose.

Automatic transmission: regular fluid changes are key.  If this hasn't
happened through it's life, it's probably living in it's golden years
now.

Electrical gremlins:  All BMWs have them.  Which ones appear, and when,
is
the variable.  Find a good electrical contact cleaner, such as:

http://www.caig.com/prod.htm

and apply it to electrical connectors that are carrying intermittent
signals.


*
I have 137K on my 92 325i and the only problem that made the car
undrivable
was the TPS failure.  Car started and just plain not driving, sputtered
home
parked it, checked the codes, got the TPS code, one phone call and I had
a
new one the next morning.  Very easy to replace.

The early cars had plastic impeller water pumps and gave problems, my
car
which I bought with 76K on looked like it had been done.

These cars have timing chains rather than belts, and are supposed to
last
the life of the engine so no worries there.

I personally think that you are better off saving your money for
whatever
does break and maintainance of course, rather than wasting resources
replacing things that may give you no trouble for another one hundred
thousand miles, like an alternator.

I would definitely do the radiator and all water hoses by 150K, just an
arbitrary number, I think they are replaced on condition.

This is an interesting subject to me for obvious reasons, so what do
other
people think?

*Here's some common things:
* Water pump. Early e36s m50 (and m52s?) have a water pump with a
plastic
impeller. It breaks sooner or later. If you are lucky (as I was) this
causes
overheating only, and in fact I was able to drive the car to the shop by

turning the heater on high and going under 60 mph. It was not a hot day.
If
you are unlucky then the pieces of the impeller lodge themselves
throughout
the cooling system.
* Radiator. The plastic neck of the radiator where water enters and
leaves
can break. Probably would render the car undrivable.
* Rear shock absorber mounts. They can break. Not catastrophic. Can be
detected by a clunking sound from the back.

That's all I know of. I personally had a short in the instrument panel
that
caused the car to keep running when the key was removed, but I have not
heard this from anyone else.

My response:

Thanks for all the info. folks.  I'm pleased to report that my water
pump and radiator, rsm and shocks, control arm bushings and ball joints,
guibo, belts, and battery are all new...so it looks like the fuel pump
might be next for me!

Cordially,

Doug

- --
Douglas M. Max
http://www.LRcom.com   Business writing and speaking skills
training--on-site and online

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