BMW 7-Series Maintenance and Repair

czma

Hello All:

I was out for half year, and I dis-connect the battery for my 97 740il. I came back over the weekend, and I was able to start the car after I put the battery back on.

Here is the problem: at the early begining, I couldn't lock/unlock the car/truck by using the car key. So that I have to do it manually. And then two days later, all a sudden, it works fine! I can lock/unlock the car by using the car key.

And now I still have another problem on the trunk. If I want to unlock the trunk, then I have to RE-LOCK the car again, and use the key to unlock the trunk manually. I remember back to the old days, if the car doors were unlock, then I can go ahead to push the trunk key-hole, and the trunk will be unlocked.

Does anyone know how to fix it? I called dealer, and they said it will cost me $79.99 to reset. And this is too pricy. Thank you in advance.

f1buick

you didn't say what year your car is. makes a BIG difference.

you could try your own "reset" by disconnecting the battery negative ground cable for about 30 minutes. seems like you cpu is confused and stuck in some sort of software anomoly. before doing this, make sure all of your physical systems are as close as possible to the same position, i.e., the locks all are unlocked. hopefully, when you reconnect the cpu will reset itself with all physical systems "synced".

swschrad

unless you like paying the dealer to unlock the radios.

czma

f1buick/swschad,

My radio is OK. I just don't know how can I reset the computer. Can you give me some more directions? Thanks!

lloyd7196

Only a month after leasing a 2001 740il, with only 14,000 miles, went thru carwash and front body colored outside mirror cover came off, all 4 tabs inside seemed ok, so just hooked back in and still a little loose, is there an epoxy that should be used to keep cover from being so loose? welcome any ideas for help,

Second question, notice black weatherstripping inside front right door was painted with must have been door area, rubber is black on left side (painting is also on same side mirror cover came off), some body painting was done, job is perfect, dealer knows nothing, nothing showed up on Carfax, is ther another way to find out history of 740, and if details of work done? BMW Corp. said I can go to original dealer, but not sure if any record, anyway to find out exactly what work was done?

Mr_Shiftright

Carfax won't show fender-bender type damage, only if the car was totalled. It might have been shipping damage. Most states allow dealers to repair minor damage to new cars without telling the customer. I think it's around $499 or less in California at any rate.

As for the mirror, don't do anything so permanent as epoxy. Perhaps a silicone that sets up would be better.

mge

I just bought a 1999 740i. I think I may have done something to the computer because I turned off the engine and tried to remove the key and turn the key before realizing that I had not put the car in park. Now when I start the car The air light come on goes off and then comes back on and stays on. According to the manual this means there is a malfunction un the system. Can I try to reset the system by disconnecting the battery. I have the navigation system so by disconnecting the battery will this cause more problems with the system.

tlcman

I have a 2000 740 iL with the navigation system, Countless times I have been careless in pulling it into my garage and push the shifter up from 4th not drive, into N or reverse, if i put it in N i usually catch my self. But when I put it in R, and shut my car off, then realize that its not in park. I turn the key to the on position not starting the car and shift into park. Disconnecting the battery in any BMW is a very hairy situation, first of all you hard boot the computer and erase the code, so you have to re-enter it upon startup (well at least on my last few bmers) this is a anti-theft device installed by bmw. If you have not disconnected your battery STOP!!! do NOT disconnect it, it will be a nightmare most likely, The best that I can say since im not a BMW mechanic is take it to you local BMW service department, have them look at it. Or call them which ever works
Hope this helps.

nvbanker

Wow......This is way too tempermental for me.

f1buick

My gawd! Tlcman, you clearly are slave to your local dealer's service department! I sympathize with someone who is so terrified of performing the simplest operations on his vehicle.

I've disconnect the battery on my 93 750 on several occasions with no problems whatsoever. In fact, there is a panel under the right rear seat cushion, with a negative ground connection for exactly that purpose! Disconnecting the battery resets the antitheft codes, but all that means is that you have to punch the codes into the radio and on board computer. Why is this some sort of big problem?

tlcman

After buying an 80,000 dollar car i would like someone a little more prone to work on my car. There is a difference between the 93 and 00 correct me if I'm wrong but they only made one type 750 in 93 thats the iL. On my BMW and from what i take on Mge's 1999 BMW we have the navagational System which for some reason is slightly more complicated than the radio... Read the Manual Mge.
I am completely terrified to do simple projects on my cars and trucks. Thats why I have a 1994 LandCruiser that i have put a lift kit, Kumara Turbo Charger, and rear differential lockers on it with no help from any service department besides the one that i purchased the hard wear from.
I have owned a 318 i (88-90) 535i (90-2000) and currently a 740iL (2000-present) I take pride in the BMW's that I have owned and would not want to screw anyone elses up.
For all we know disconecting the battery might not do a hill of beans. Mge just shoot you local dealer an e-mail, they might beable to tell you in a response

jchenirvine

Hi all,

I bought my 97 740il a little over a year ago and have begun noticing that it sometimes shakes a bit when I brake at about 40-50 mph. It still drives really smooth at high speeds, but this shaking is frieking me out. Any thoughts before I go to the dealer? Thanks!

alcan

That's usually the symptom of a warped brake rotor. Any shake in the steering wheel under braking?

tlcman

How many miles does it have on it? alcan is mostlikly right, you can try this but because its a BMW i would doubt that you would feel anything,,, Ok when slowing down at a stop sign / light push the brakes a little harder than usually but not to a skid, and see if you can feel any response in the peddle, If you do then it is the rotors. Also check your brake fluid. Do you drive the BMW like a sports car or like a regular around town car?

jchenirvine

Thanks for the quick responses alcan and tlcman -
I tried what you suggested tlcman and didn't feel anything in the peddle. The shaking/vibration also sometimes occurs when I'm on the accel, but only right around 50mph - any faster or slower and it's pretty smooth - and it doesn't occur on all roads, definitely a strange problem. Someone who had a similar problem thought it may be a balancing issue (I recently went with new 18" M-parallel wheels with Conti sport tires) and suggested I get "centering rings." What are those? Any thoughts? Thanks guys.

nvbanker

If you have aftermarket wheels on it, that could easily be your problem. If you still have the old wheels, put them back on and try it. I'll bet the problem goes away. If it's not the wheels, or one of the wheels, it could be one of the new tires. A front to back rotation would prove that out for your.

The steering is very sensitive on the 7-series, and any imperfection in balancing or roundness can be detected at the critical speed. As expensive as they are, many aftermarket wheels are not well balanced or round like the factory wheels are.

jchenirvine

If the problem is that the wheels are not round, what's the fix?

nvbanker

Different wheels...See if you can take them back and exchange them, or find the one that's bad and demand a replacement maybe? If they're all goofy, get another brand. Frankly, on a car that precise, I see this a lot. There's nothing better than the factory wheels on a BMW for true handling. On a Chevy, you'll never notice, but on the BMW, any little imperfection will be magnified.

tasillo

My 2000 740iL (18" M-Parallel wheels) recently developed a similar problem while driving (not braking). I know I was on my way to needing new tires, but did not notice a balance problem at any other speed. Also, on one ocurrence, I hit a small bump while accelerating onto the interstate. The wheel began to shake pretty violently until I hit about 60 mph. Pretty similar to headshake for any motorcyclists out there.

I checked with my local high-performance tire dealer who told me he sees this problem frequently on BMW's when the mileage starts to creep up. Normal wear on the suspension/steering components make them extremely sensitive to tire wear patterns, balance and quality. I replaced the tires (Pirelli PZero Rosso's) last week with Michelin Pilot Sport A/S. Presto, no more problem! I will say that the steering does indeed feel "looser" than it did at lower miles. Anyone know of an adjustment that reduced free-play in the steering?

If you 18" wheels are not OEM, make sure they are "hub-centric", or fit snugly around the hub or dust cap. If there is any free play, you'll never get the wheels to stay in balance as they actually shift on the hub. I had this problem with some beautiful Centerline wheels on my Suburban, and Centermine did not make a centering ring for a good fit. Ended up replacing them with Axis wheels which are hub-centric and no more problems.

For anyone contemplating new tires for the 18" wheels, steer clear of the Pirelli's. They rode beautifully when new and were much quiter than the Michelin's. However by 6k miles they began to cup and get extremely noisy. The dealer rotated them (side to side) which did not help at all. At 12k miles the noise was intolerable and embarassing. Also, the rear tires were worn to the center bars. No better experience with the Continentals either!

tlcman

But before you replace your tyres check your air pressure. Make sure that it is correct. I had a similar problem with my old 535 i and it turned out to be low tyre pressure, and it created a very distinct wear pattern.

eworker1

I'm having this problem too. 1998 740iL. Pulled Continental Spare out of trunk, bought a match, and placed them both on the front, on or about same time as new front brakes. Put old worn out Michelin's on and reduced the shake-when-brake. Alignment expert says the wobble should not have harmed steering components. Hope it's true and off to replace tires, I guess. Any other advice?

tlcman

mostlikly just the tyres,,, continental has made some pretty cruddy tyres for BMW's i personaly like Michelins or Goodyears. and remember that the 7 series has a very sensitive steering and fron shock system... i do take it that the new tyres were balanced correctly right?

nvbanker

Continental makes pretty cruddy tires for everybody, I found out through experience....

eworker1

Thanks nvbanker and tlcman. The tire dealer called yesterday and confirmed that Continental was OEM for BMW 740iL spare tire. Interesting, maybe I just got hold of some bad tires. I have an appt tomorrow to see if brake rotor is warped, or was re-surfaced leaving less than the required 1.118 inches width on the rotor. (They call it "discharge of 1.118"). Yes - the tires were balanced by computer, then taken to an old speed balancer where a device is rolled up under the car and the mechanic held a "card" against the tire, showing the Continental tire was "out of round" - but they say that all tires are slightly out of round. And - I have same wobble when putting a worn out Michelin back on it. That's the last Continental I'll buy. Am I on the right track in isolating the problem? Do you think I have worn out steering components or shocks/struts?

eworker1

The problem was that the last shop to replace brake pads resurfaced the rotors to 1.006 width (discharge) when you should never go below 1.118 inches. Everything is back to perfect. Hope this helps someone else out there.

nvbanker

Interesting. Only on a BMW would you notice that.

f1buick

I'm not sure how well this translates into the E38 chassis (1995-2001), but both the E32 (1988-94) and the 5 series E34 have EXACTLY the problem described by eworker 1. The problem can be exacerbated by bad tires/rotors, of course, but that is more of a symptom than a solution.

The specific cause is (are) the upper control arm bushings, or "thrust arm" bushings as they also are called. They take a big load during braking and tend to wear out rather quickly on these very heavy and agressively driven cars--I got 55k out of the originals before vibration set in.

Unfortunately, before I discovered the root cause I managed to burn through a set of new oem rotors in only 12,000 miles--everything seemed "cured" for about a year and then the vibration returned. The next time around I replaced both the rotors and the bushings, and things returned to normal.

feedwater1

I've got a 1997 740il that's producing a noise that sounds like a tape deck changing tracks. It's not that loud and there's no tape in the deck.There is also a clicking sound coming from the same area.It sounds like something is trying to reposition but never succeeds. has anyone ever heard anything similar to theses noises.

f1buick

those are the electric stepper motors for your vent system (open and close the vents). one of them either is off track, or it is confused about its position and is bumping up against the limit of its motion range. I've had one doing this intermitently for about 60,000 miles, in the same area you've mentioned. they are an absolute pita to get to and not worth fixing imho. my hvac continues to work just fine.

idean

I recently drove into a snow bank with my 2000 740il, after I drove off I noticed the external temperature gauge going from -20 to -40 finally stoping at - 40 . I guess I must have broken the extenal sensor , does anyone know where it is located and how to change it .

nvbanker

You may have just put it into the snow, it may not be broken. But they are usually located behind the grille somewhere, in front of the radiator.

revjj

I am interested in purchasing a '98 740il that has 73,000 miles. The current owner admitted the car had overheating problems last summer. The radiator and water pump were both replaced. While test driving the car today, it overheated again. Is this a common problem with this model, or year? Is there anything I need to be aware of? What could be the problem? Thanks for your help.

Mr_Shiftright

No, it's not common and it could be extremely serious. I wouldn't even look at the car again. It may very well have been damaged from overheating, and the fact that the owner is trying to sell it "broken" is a very troubling sign. Not a car for the faint of heart. You don't want to have to dig into that engine.

nvbanker

AGREED!!! El Paso on that one......unless you can get it for $500

Mr_Shiftright

Actually I don't know the retail value of the car but I do know that a basic head gasket and valve job should be about a cool $10,000 if you do a bangup job. you aren't going to pull just one head, and then while the engine is stripped down there's the "while we're in here factor" regarding belts, hoses, injectors, sensors, wiring, etc.

 And if you have any kind of cylinder wall damage, well, god have mercy on your soul.

nvbanker

Not to mention, that if you do the top end, and restore compression to factory specs, the lower end will be overly weak, and the engine may smoke, so you ought to do the whole thing. And, frankly, that whole engine sounds like toast to me.

Mr_Shiftright

Overheating is double-scary on a car like that. If it were a Chevy 350 I wouldn't be so concerned, but on this car it's too risky.

f1buick

The theory that restoring top end compression will result in a lower-end failure is incorrect--the shade tree mechanics version of an old wives tale. Restoring the seals places very little additional stress on the rings. I know mechanics who have performed scores of head jobs on high-mileage engines without problems (only done it twice myself, but also with no problem).

Regardless, I agree that you absolutely do NOT want a BMW that has overheated. BMW uses a torque-to-yield head bolt system, where the bolts are INTENDED to fail in the event of overheating. The reasoning is that by failing the bolts, stress is relieved on the head and block castings, preventing warpage. And that is, in fact, what happens: The block and heads (heck, sometimes even the gaskets) survive unscathed, but you are stuck paying major dinero to a mechanic to dig into the motor and install a new set of bolts, provided he will do this and will not cover his hinney by insisting on a complete rebuild.

Mr_Shiftright

Well that's the point, you aren't going to "patch up" an engine like this once you've opened it up. And if the overheating was frequent, even fail safe engineering might not have worked.

tlcman

I have a 2000 740iL and on a few long road trips, I have opened it up in Wyoming and other empty long stretches of highway. Even running at speeds upwards of 130MPH probably for about 10 mile stretches, and when I was purchasing it I drove it at the BMW testing grounds, I noticed minor changes in temperature. I was just wondering how common this problem is and did BMW make a mistake (which is hard to believe, but occasionally happens) or is this just a case of vehicle neglect? I have owned a 325 e (85) with no problems, 535is (88) no problems, and the most recent 740iL (2000) my pride and joy with no problems. I would assume that this is vehicle neglect

Mr_Shiftright

You mean your own neglect? Do you flush the coolant every two years? Other than that, I can't think of anything that would be your fault.

Also, relying strictly on a gauge to give you the facts isn't always the best idea. Gauges are usually electric and hence subject to voltage variations, which affect readings. Also, I suppose you could have a little air in the coolant system. If coolant was ever added with bleeding it, that might be a possibility.

sure BMW makes mistakes. Ask anyone who ever had the upper plastic neck of their radiators crack and blow off.

tlcman

I never have neglected my vehicles I always make sure that they are all running perfectly, I was just wondering if in this case, the overhearing 98, if this was a case of vehicle neglect. Or if it was a common problem which I doubt

vcheng

....thermostat cycling can create minor temperature fluctuations on the guage, particularly under high load conditions such as steady high speed running.

Mr_Shiftright

Yes but didn't he say he was running in the desert, or did I misread that to mean "hot outside". I guess the desert gets pretty cold too sometimes.

vcheng

...."on a few long road trips, I have opened it up in Wyoming and other empty long stretches of highway. Even running at speeds upwards of 130MPH probably for about 10 mile stretches,..."

Maybe your interpretation is correct. I was just mentioning that given the load conditions, ambient temperature, and water pump flow, minor oscillations of the water temperature may be a normal operating characteristic. However, wild fluctuations would still be abnormal.

tlcman

130MPH for ten miles is less than five mins. Not a very long time for a car with five gears, and sport tyres and rims

revjj

Again, I the guy in post #33 interested in purchasing a '98 740il that has 73,000 miles. The vehicles repair history from the dealer shows in May of 2001 when the car had 56,000 miles that it was running hot. The dealer replaced the radiator and water pump. The car now has 73,000 miles. Would not any engine damage due to overheating manifest itself soon after the overheating? Over 2 years and almost 20,000 miles later the car is running beautifully. The recent overheating on the test drive was due to a lot of air in the cooling system from an improper bleed procedure after a hose was replaced. Thanks for your help.

trimaster

Hello Room,

I own an 88 735i. Today I turned on the A/C (I live in Florida) & the air was VERY weak on both the driver & passenger sides. It worked just fine the last time I used it (about 4 months ago.) I'm not mechanically inclined & I'm fearing the worst. Any idea how much this will cost me to get fixed? (Other than this the car runs great 201k miles.)

Mr_Shiftright

I think you need to have them "read the numbers" on the A/C. Some likely causes would be

a) freon leak that needs to be sealed and refilled (couple hunnert bucks tops.

b) dessicate bag in the dryer has exploded sending particles into the expansion valve, clogging it. (very typical 735 trick). Figure 6 hours labor and $250 parts. (dryer, valve, freon).

c) your compressor is getting weak and this has similar symptoms to a clogged expansion valve.

If you know where the expansion valve is you might tap on it with a screwdriver handle and see if that does anything.

f1buick

to answer your question, "yes the damage would have manifested, but the problem is DETECTING it." Modern engine with computer management systems are so good at "running beautifully" that you can have a problem and not be able to detect it just by listening. Heck, I blew a head gasket on my V12 and there was no audible indication from the motor.

At the very least you should have the engine compression tested before purchase. If there is more than 10lbs variation between cylinders, don't buy it.

Mr_Shiftright

You mean 10% variation? 10 lbs sounds okay unless BMW has a lower tolerance than most engines.