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Mechanical things you need to know about your E34 - UPDATED 3/22/11

191K views 100 replies 57 participants last post by  BMWe34Steve 
#1 · (Edited)
Stomp Test Procedure moved to top of list 3/22/11

Hello fellow Festers. This is a thread designed to be comprehensive in nature and assist current and new E34 owners with some of the common problem areas and failures of the E34. Please feel free to add to the list as I'm sure that I will not remember everything. I will update the original list accordingly. Of note, I will only plan to add things to the original post that are known problem/failure areas, preventative measures one can take and the recommended fixes that are universally accepted and recommended. Some have suggestions that are "unconventional" that they have had success with. There is a thread coming for those suggestions. This list is compiled from my years of owning BMWs as well as the experience of others who have basked in the glory of the mighty E34. There are some caveats with this list due to the varying models of the E34, but it should be a good list to cover most situations/models.

First things first …......... Obtain a copy of the Bentley manual. It is by far the most comprehensive repair manual for the E34. Here is a list of problems/failures that are common on the E34 and preventative measures.

Stomp Test Procedure

I decided to move the stomp test procedure to the top of the list. This is absolutely the first procedure that should be done to diagnose a problem (unless of course your radiator is puking coolant due to a busted hose or something obvious like that) Our BMW has a computer (OBD I - on board diagnostics I) that will store fault codes if it detects a problem with many of the components of the car. Per the Bentley manual, this works for 1992-1995 models only. This is one of the very first things that should be done if you experience driveability problems or if your check engine light (CEL) comes on. Many have asked how to perform the stomp test. I decided to create a thread dedicated to this procedure. Follow this link for the step by step procedure with the associated fault codes:

http://www.bimmerfest.com/forums/showthread.php?p=5936965#post5936965

Cooling system

Do not let your engine overheat !!! This cannot be stressed enough. If it gets to the red zone, it is in danger of major damage including a blown head gasket and/or a cracked head. This is a very difficult DIY and very expensive if done by a mechanic. The E34's cooling systems is its Achilles heel.

- One may want to consider a complete cooling system overhaul every 100K miles or so. The best case scenario is replacement of the radiator, belts, hoses, pulleys, water pump, thermostat, thermostat housing, fan clutch, fan, radiator cap and bleed screw. Of note here, there is a special fan holding tool that is invaluable to removing the fan assembly. A 32 mm wrench is required for the large nut holding the fan clutch to the water pump shaft. This is a reverse threaded nut, so the wrench has to be turned clockwise to loosen the nut. The holding tool and wrench can be obtained online for about $30-$35. It is money well spent. Believe me, I know because I ruined a water pump pulley trying to use the inappropriate tools. A regular coolant system flush can help stave off some of the problems. A coolant system overhaul is not a difficult DIY on the E34. Please see post # 10 for two very good videos on the BMW coolant system (thanks Bluebee :thumbup:) While the E34 is not listed, virtually every single thing in the videos apply. The only real difference is the location of the bleed screws. In fact, the radiator in the second video appears to actually be an E34 radiator.

- Some of the parts of the cooling system from the factory are made of plastic that, over time, will fail. The upper radiator neck is a common breakage point. The plastic bleed screw can fail/break easily. Be careful not to over tighten the bleed screw as it should not take a lot of torque to get it to seal. Brass replacement bleed screws are available that are very nice looking and will not break.

- If replacing the fan, it is universally recommended that you only use the oem fan as the aftermarket ones are of inadequate quality and are prone to breaking apart. The fan clutch is an item that can fail. When new (and the engine off and cold), the fan clutch turns like the internals of the clutch are like molasses. If it turns with virtually no resistance or it will hardly turn at all, then it is time to replace it.

- The factory water pump comes with a plastic impeller that over time will disintegrate and cause an overheat situation. There are water pumps available with a metal impeller as well as ones available with a composite impeller. It is a universally accepted recommendation that the plastic impeller water pump be replaced with the metal impeller water pump. There is also a high flow water pump that is pricey, but is reported to flow much more coolant. It is commonly used in racing situations. The thermostat housing is made of plastic and there are aftermarket aluminum housings available. The design of the thermostat housing is such that a sealant is not required if all mating surfaces are smooth, straight and properly cleaned. However, premium high temp thermostat gasket sealant can safely be used as an extra measure (thanks LD), just be sure to not use too much as it may get into the coolant system. The t-stat for the E34 comes in three different temperature ratings, 80, 88 and 92 degree Celsius. My recommendation would be to replace with the one that came in the car from the factory. Some opine that lower temp t-stats allow the engine to run cooler. Others say it only allows the engine to cool sooner because it opens at lower temps. Do your research as the jury is out on this one.

- BMW recommends its brand of coolant only, but it is pricey. Some suggest that you can safely use less expensive coolant that is green and has a sweet odor. This can aid in visual discoveries of leakage as well as being more apt to smell coolant if it is leaking. Many have had good experiences with the lesser expensive brands. There is a very detailed thread on this here : http://www.bimmerfest.com/forums/showthread.php?t=523954

- Many feel that bleeding the coolant system is as difficult as brain surgery, but if done according to the Bentley manual, it is not difficult and can be done in one to two bleeds. Of note, the 540 reportedly has a self-bleeding system. One key is to make sure your heater is on full hot and the fan is on maximum. You can also elevate the front end 6 inches or so to help the air move up and out of the system. A sign of a coolant system that has not been completely bled is an overheat situation in combination with no/little heat from the heater.

- If allowed to overheat, the head gasket can fail and/or the head can crack. If this happens, it is bad. Signs include an engine that continues to overheat and loose coolant despite topping off. Of course, if one just loses coolant, the one should examine the entire system for a leak. Other signs include milky looking oil, oil in the radiator, bubbles in the expansion tank when the engine is running and large amounts of steam coming from the exhaust pipe. A compression test and/or bleed down test are two of the more definitive tests for a blown head gasket and/or cracked head. The oil and coolant can also be sent off to be analyzed.

Fuel system

- The fuel system can present instant or insidious problems. Frequently a car will not crank well, be low on power, have severe hesitation or just suddenly quit. The best way to address the fuel system is in an orderly fashion. First check the simple things, i.e., make sure you have gas in the tank (sorry, but it happens). Next, check the fuel pump fuse. If bad, replace. If not proceed. If you have a can of starting fluid, squirt it in the air box for about 2 seconds. A word of caution here, the MAF has a wire that heats up and can potentially cause a fire with the starting fluid, but I think that is rare as hen's teeth. Anyway, if the car cranks and runs for a second or two, you have essentially narrowed the problem to a fuel delivery problem. If this is the case, then you need to proceed with a little more detailed diagnostic procedure.

- If the fuel filter has not been replaced in a long while, then you should replace it. BMW recommends that it be replaced every 30K miles. Some feel that they can be cleaned, but again, I am sticking with recommendations that are either recommended by BMW or universally agreed upon. Now you need to check to ensure that there is power to the fuel pump. This is accomplished with a multimeter and by jumping two terminals in the fuel pump relay socket (#30 and 87). Here are a few pictures of the jumper I made according to Bentley manual instructions.

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- I will not go in to great details on the socket jumping procedure here because the information is here in this link kindly provided by Roberto (it's from the Bentley manual that is a must for E34 DIY'ers).

http://www.bimmerfest.com/forums/attachment.php?attachmentid=269572&d=1299708539

- If the fuel pump purrs when the sockets are jumped, then the fuel pump relay is bad. It is a very good idea to have a spare fuel pump relay with you at all times. If the car suddenly stops on you, you can simply replace the relay. If that is the problem, the voila, it is now fixed. If the fuel pump does not purr with the relay sockets jumped, then the pump is likely bad. It is possible that it is the wiring from the FP relay to the pump, but that is unlikely. Sometimes the pump is just weak and in early failure. This can be tested by checking the fuel pressure at the fuel rail. I am not very familiar with that process or the pressures that should be present. Someone please chime in here. Finally, the injectors may not be firing or may be clogged. They can be tested with a multimeter and there is a flushing and back-flushng procedure as in this video:

.

Thanks Roberto :thumbup:. It is very uncommon for the problem to be fuel injectors if there is a sudden no-start situation or if the car suddenly dies while driving it. The fuel pressure regulator can also be a problem, but it is not very common. Someone may be able to chime in with more information and I will add it here.

BMW factory radio code reset procedure. Here is a direct quote from the BMW anti-theft radio owner's manual:

"To enter your security code, which can be found on the two cards supplied to you by BMW, turn the radio on and use the appropriately numbered radio push-button selectors. If the correct code is not entered in three successive tries, the radio will not accept another entry until it has been left on for one hour.

Important: If you make a mistake in entering your code, complete the entire sequence before entering the correct code. For example, if you r code is 12345, and you mistakenly enter 125, finish the five-digit sequence (45) to complete that entry. The radio will not operate, and the wok "CODE" will again appear on the display. Enter the correct code this time.

Exception: IF you hear a beep when entering your code, stop immediately! Begin entering the code again, starting with the first digit."

More to come later :)

Steve
 
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#41 ·
^ Coming from the 3er side of things where we consider engine swaps common things to do when bored, I say yes, you can put any engine in any ting if you want to badly enough and don't mind spending the money.

Now, on to my silly question:
I drive a 325IS which I love and is fantastic in nearly every way, one of it's short coming however, is cargo capacity and since I spend a fair number of weekends in a kayak or a canoe I find myself want a second, larger, car. I've been looking at buying an E34 525i touring but was dismayed to find out that here in the states they are only available with the GM slush boxes so I am wondering if a 5 speed Getrag transmission from a 3er will work?. I have a 5 speed from a 318IS and I am assuming that since the 318IS and 325IS use the same transmissions, and the 325IS and 525IT use the same engine, that the swap should be fairly straight forward. I would appreciate your insight and suggestions, and I look forward to hopefully adding an E34 to my driveway.
 
#42 ·
im having some problems with lights and other electronics such as my reversing lights not working and the rear windows not rolling down, shifter lights not working some of the instrument panel isnt working either is this all one problem or a multitude? and how can i fix it?
 
#45 ·
It certainly can be. It is better to post a question on the general forum rather than a sticky dedicated to common medhcanical problems.

In regards to your questions, there are a lot of things that it could be. The electrical systems on these cars can be a bear when they reach the age of our E34's. Reverse lights not working is usually a problem with the wiring in the loom running along the left trunk hinge. Expose the wires and take a look for any that are frayed or worn through. The rear windows not rolling down could be a fuse, switch, window motors, regulators, etc. We have to have more information as to what happens when you press the switch. You may need a new instrument panel or there may be a bad connection or one of your fuseable links may be bad etc., etc.

Don't take Wis's comment too personal. We just need more info to help. It may be good to address each problem one at a time.

Oh, and yeah, you need to grow just a little thicker skin. Most of the guys around here are really great to chat with for ideas.

Welcome. I hope I have helped a little. Try posting a question about one problem on the E34 forum (note the sticky thread) and see what kind of responses you get.

Steve
 
#47 ·
I'm sorry, but I don't know for sure. I would think that it is more likely than not that they will match up, but can't say with any certainty.

Steve
 
#50 ·
Whatever you're willing to pay for it :D

My guess would be $300-$500 if purchased from an individual, maybe a little more from a company that sells used trannys. If you can find the right salvage yard, perhaps $100-$150.

BTW, this is the type of question that would probably get more responses from general E34 forum. I want you to have the benefit of the knowledge of everyone here. I don't know that they check this thread much anymore.

Steve
 
#54 ·
Hey dogg. It would be better to post this as a new thread. Also try to give a little more info. I don't know a lot about the trans program error, but I have seen people post about it and they find that their alternator is faulty. There are a lot of other reasons that it could be doing that though.
 
#56 ·
They do require a lot of TLC. A full on coolant overhaul should cost ~ $600 in parts online. You may be able to find a better deal if you find a kit for the full system.
 
#58 ·
Hi everyone....
Please bear with me, I am a rather girly girl without mechanical expertise but if my experience helps someone, it was worth trying to explain my overheat issues and resolution.
So.....she kept overheating, and hoses would burst, etc. I had thermostats replaced, radiators flushed, hoses burst and replaced...on and on and on...finally I researched and paid some mechanic 27$ for online advice and was told that this model often has problems with the fan....it doesn't stop turning...so mechanics miss it....but the silicone gets cracked or something like that and it turns SLOW....too slow to properly cool the car. I told the mechanic this, he replaced the fan and VOILA... she chugs along with the gauge at the perfect spot all the time! It is so fabulous!
Now...I had the shocks replaced and am having bizarre draining of the battery...been in the shop twice and it's still happening. The mechanic took out my chip to help with my atrocious mileage in the city (8 mpg), not sure what the chip was (Dinan?) but it did seem to help a little but now have this weird electrical problem which I described in another thread. Help anyone?
 
#60 ·
Yeah, the thread closed out (it would not let me update it) after a certain time frame and I never got to the shimmy issue.

The front end suspension and steering components wear out on these cars in about 100K mile intervals. The infamous shimmy usually occurs as you hit about 52 mph and continues until about 57 mph or so. The most common cause is worn thrust arms. It can be the bushing, ball joint or both. However, other worn components can cause it as well. It can also be brake rotors that are warped (although this usually only causes shimmy when braking) or out of balance wheels/tires. It is best to rebuild the entire front end all at once, but it can be costly if you plan to use premium parts.

I just rebuilt mine and the parts alone were about $660. Keep in mind that I used Lemforder parts because I plan to drive the car for another 150K miles if possible. A company called FCP Groton sells front end kits that are much, much less expensive. However, there are mixed reviews on the quality and durability of the FCP parts. It is a lot of work to rebuild the front end and I just didn't feel like gambling that I might have to do it again in short order if I used the less expensive parts.

If you are on a budget and want to try to eliminate the shimmy at the least cost possible, I would start with replacing the thrust arms. Mind you that there are special loading requirements when torqueing the bolts down. Unfortunately, I didn't follow those specific instructions because I did not have 500 pounds of ballast available. I am in the process of trying to come up with a way to produce the ballast (friends that weigh 150 pounds each, bricks in boxes, free weights, etc.) and plan to re-torque the bolts once I come up with a workable solution.

Good luck with getting your baby into shape.

PS: regarding your tire issue, you need to invert and rotate your flux capacitor hyper-inflator :D
 
#62 ·
Hello - Well, after reading all of this thread and watching the videos, it looks like I am not alone when trying to figure out my cooling problem. My ride is a 1990 525i, 159,xxx miles. The temp gage shows the engine is running hot, but I can not find anything else to tell me the temp is too high. No steam, no hissing noise from the radiator, no sign of a coolant leak from the head gasket (or anywhere else), ect. The thing that stumps me is how fast the temp gage goes up. According to the temp gage the engine is at operating temp within about 20 seconds of starting the car (engine dead cold at start up). I've never had a car that would warm up so fast! Is it normal for a 525i to warm up so fast?
Temp gage will slowly keep going up until it hits the 3/4 mark. Then vary slowly keep going up a little more. Looks like the needle will barley get into the red when the engine is ideling for an extended amount of time (as an example, I had the car ideling in my driveway for about 20 minuets, temp gage needle was just barley touching the red. While driving down the road, needle was not in the red, but was a little bit past the 3/4 mark on the gage. Turn the heater on full blast, the gage will go down a little. Rev the engine to 2500 RMP & hold it there, the temp gage goes down a little more).
Is it possible that the temp gage is not accurate, or is there an actual cooling problem? Is there a way to tell the temp of an engine other than going by the temp gage (some sort of diagnostic tool)? Is there a way to test the temp gage itself?
I just replaced both temp sensors (the 2 in the t-stat housing), no change in the temp gage. Check engine light was on, code was for a temp sensor. Check engine light went out once the 2 sensors were replaced. Coolant level was a little low, but not much. I topped off the coolant, no change in the temp gage.
Previous owner said he replaced the t-stat, t-stat housing & water pump. Maybe a few hundred miles on the car since these parts were replaced. I have no idea which t-stat he used, or what brand the parts are.
Temp going up to the red while ideling leads me to believe the problem is with the fan, or fan clutch (not enough air flow over the engine???). But i'm confused by how fast the engine warms up.
I'm a little hesitant to overhaul the entire cooling system if the problem is just the gage, but I also don't want to damage the engine. After watching the videos in this thread, I now know how to check the fan clutch, but what else can I do about this problem?
Thanks in advance!
 
#63 ·
Jay, note my post above: it was the silicone around the fan that had worn out...thus the fan spun too slow (initially missed because the fan did indeed spin). When that taken care of the engine hasn't overheated even once in the past two years. I spent hundreds and hundreds to try to resolve the issue before that point...simple and cheap answer. Apparently it's a design defect, the silicone doesn't last....hope that helps!
 
#65 ·
You didn't tell us what year car you have :spank:

If it is a 91-95, there is a washer pump relay located in the front power distribution box which is on the driver's side (here in the states - not sure if yours is opposite). I would check that. It seems that perhaps the contacts within the relay may be sticking. It would probably be an inexpensive relay.

It is covered on page 610-1 of the Bentley manual.

Hope this helps mate :thumbup:
 
#66 ·
yes my steering wheel is on the right side :) as for the manual, the hard copy I gave it away when I sold my 89 model because I didn't imagine I will miss it so much and buy another one, and my hard drive sort-of burned las week and I kinda lost everything. But thanks for the info, I will look for a manual now and see how it goes

thanks
 
#67 ·
Car stalling while driving

Hi guys i need help! I have a 89 BMW 535i 5 speed, it was having problems starting it would take a few cranks before it started. I took it to a mechanic and he did a tune up (changed the spark plugs, gas filter ect) he stated that my gas line had a lot of air in them for some reason after the car was cranking fine after driving it on the freeway it stalled on me twice and started the cranking issue again. now i cant go one mile with out the car stalling on me. It seems worse then before pleas help.
 
#68 ·
Hi guys i need help! I have a 89 BMW 535i 5 speed, it was having problems starting it would take a few cranks before it started. I took it to a mechanic and he did a tune up (changed the spark plugs, gas filter ect) he stated that my gas line had a lot of air in them for some reason after the car was cranking fine after driving it on the freeway it stalled on me twice and started the cranking issue again. now i cant go one mile with out the car stalling on me. It seems worse then before pleas help.
Best to make a thread about the issue or research the problem.
Very few of the vets check this. It's mostly info for the new comers.

And welcome to the fest
 
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