Common problems on an E34 540i.

[CharlesAFerg]

I currently own an early M20 525i, and it's got a lot of problems. I was wondering what you know specifically are issues that show themselves in these, later model E34s, specifically the 540i.

When I search online, all I seem to find is wrong information from people using E39 issues and applying them to the E34. I already know what goes wrong with the E39 540i and E38 740i, but I am curious about the E34 specifically.

Besides the Engine linings, what else is common?
The biggest problems in my E34 are electronic issues due to the clusterboard going crazy, and nobody seems to be able to repair it. (I even bought some replacement boards, but it seems like most of the people rebuilding them have given up rebuilding and just send out bad boards from old cars, because he sent me two bad boards which were plagued with completely different problems - yet the problems were all rooted in the board.

Next, is the coolant leak from the old heater core. This is a big problem in all E34s, so obviously not specific.

The electronic issue seems to be the biggest pet peeve of mine at this point.

[mikell]

Mine is the small M60 - the 530 - but there are a lot of cam cover seals and such that do seep after a while and changing them is a big pain. But rubber goes brittle in any car after 15 years. I've been pretty lucky - no major issues beyond routine maintenenace. At 295,000 miles, I'm just now starting to burn some oil, but it's hard to gripe about that. Electronics could probably happen to any version E34, I suppose.

[Bob in San Jose]

I have owned my 95 540i for the last 10 years and have the following recurring problems.
Radiator replacement 3 times about every 3 years.
Auto trans fluid replacement of "lifetime fluid" 2 times. Once at 79k miles and again at 100K miles. Was having "Trans Program" issue.
No problems with trans since and am at 172K. But probably should replace fluid again soon.
Replaced Upper control arm bushings with 850 bushings at 85K and need to be redone again now.
Instrument cluster is starting to act up so will have to address that soon.
Replaced center drive shaft support bearing about 18 months ago and just had to do it again.
Still have a slight vibration on acceleration so looks like I'll be pulling the drive shaft and having it rebalanced.
Replaced the water pump, thermostat, thermostat housing during second radiator change as preventive maintenance.
Replaced the valve cover gasket and intake gaskets at 85K miles.
Replaced all 4 brake rotors and pads at 79K (when first owned) and pads again at 125K. Just checked the pads and they are still good at 172K.
Suspension was updated to H&R springs and Bilstein sports at 110K.
Forgot to mention the front door brake tear out problem that is common on all e34 models. Fixed with a reinforcement plate from Koala Motor Sport.
Other than that only regular oil changes, tires, and 1 spark plug change in 10 years and about 93K miles.
So that's a lot but I've been happy with the car overall.

[CharlesAFerg]

Great input, I really appreciate it.

My cluster is going absolutely crazy, but the important functions remain relatively intact. My temp gauge went out last week for the first time, but is back now. I have a feeling that it had to do with some kind of short, because that night my battery died mysteriously.

Other than that, my fuel gauge is so erratic it's almost funny. The reserve light DOES work, which I'm thankful for.

My speedometer cuts out, but it seems like only during the changing of the seasons, and it gets REALLY bad.. lol

Sometimes a majority of the lower lights go out, and only come on if you 'tap' the top.

Thanks again for the info.

[Mr._Graybeard]

Engine/transmission mounts, plastic thermostat housing (get an aluminum one from the aftermarket), intake manifold leaks, PCV oil separator.

The 5hp30 transmission is, like the engine, a little finicky but basically very robust if kept up. It can leak fluid at the wiring harness connector and selector shaft, but leaks can be easily repaired. It can whine if the fluid gets low or if an aftermarket filter is used. I've used Pennzoil MultiVehicle ATF for tens of thousands of miles without any harm.

The transmission is water-cooled, fed with lines from the back of the engine. The hose ends are of better quality than a standard heater hose, but age can take their toll. I blew one of them out at BMWCCA Oktoberfest last summer at Road America. I'd look them over closely, keeping in mind that the sheathing can hide deterioration.

I rebuilt the valve body in my transmission at 150K miles. I think it improved shifting.

Of course, you can look for a six-speed and you won't have to worry about the slushbox.

[BMWDriver]

I changed my cluster's capacitors to some satisfaction, specially with the fuel gauge issues. However, on longer trips, it seems to go to empty every once in a while (when half or less), though I've not made long trips since I put in higher voltage capacitors, which is highly recommended by Shogun.

[CharlesAFerg]

Why higher voltage capacitors?

[genphreak]

Dunno about any merit in using higher voltage units, but heat kills caps. It is best to find a 105 degree ones instead of the 80 degree jobbies.

I've done all of the stuff so far listed to my e34s, except that I call leaky heater cores (and the required centre dash tear out) as a right of passage (it's a day'w work really), even though it is usually just a matter of replacing o-rings.

Never had a door brake break, not once. Haven't fitted the reinforcement plates yet, one day perhaps... they add too much weight to the car... lol

Would add to that list...

- untwisting the drivers side wiper
- re-adjusting the bonnet so the wipers don't hit it
- recovering the door cards, headliner, parcel shelf
- replacing all the heater and vacuum hoses
- replace fuel pump and FPR
- serpentine belts, tensioner
- LAD hoses and bombs if fitted
- HIDs
- door handle gaskets
- AFM (replace/upgrade to MAF)
- ICV

Hmm. I could go on forever. It looks like this could be a long thread...

We're just real lucky that fixing these things is so rewarding!