Tech Tip – Alternator Care

If you have ever had to replace an alternator sooner than you thought was normal, you may have had a hand in causing its demise. The most common reason for premature alternator failure is overheating. In an earlier tech article, I stressed the importance of adequate cooling of the alternator by keeping the alternator air ducting clear. However, there is another seemingly innocent way of causing an alternator overheat situation that can adversely affect both water and air cooled alternators alike. Any time when your car does not crank over and you get "a jump" you might be thinking, "Well, the battery will re-charge while I’m driving." You might be right, but you are also risking an expensive, future breakdown. The alternator may even provide enough surface charge to the battery to provide enough power to start the engine the next time it is needed. However, asking the alternator to run at peak output for an extended period of time will guarantee an overheated alternator and eventual failure. The alternator is intended to maintain the car’s electrical system, not act as a battery charger. As a final note: even when replacing the battery, make sure the new battery is fully charged so you don’t end up replacing the alternator next.

Tech Tip – Brake Hose Failure

Owners of 5 series from 96’ – 03’ (E39 chassis) and 7series from 95’ – 01 (E38 chassis) should be aware of a potentially serious brake system failure. The problem occurs when a main brake pressure hose section from the ABS/ASC/DSC hydraulic control unit ruptures and causes the brake system to loose hydraulic pressure. Due to age and thermal exposure to engine exhaust manifold heat, this particular brake hose section slowly deteriorates. Under braking pressure, at the point when most needed, the hose failure occurs. We at JL Motorworks have seen a number of these failures and have also identified many potential problems during our thorough routine maintenance program. The brake hydraulic system must be re-bled after the hoses are replaced. In addition, the cycling of the ABS hydraulic unit solenoids must be carried out. As an added level of protection, when the hoses are replaced, we at JL Motorworks install an outer heat barrier sleeve to protect the new hoses and prevent the problem from occurring again.

Tech Tip  - Window Regulator

The windows in your BMW seal tightly into a window channel or weather strip, when closed. During the long hot summer, the windows are infrequently operated. Heat causes the rubber weather strip/channel to stick to the glass.To raise or lower the window, a window regulator or cable and pulley system is employed. After months of non-use, excessive force is required to release the window glass from the weatherstrip. At the moment of initial restraint, the cable pulley/window regulator system can be damaged; thus, rendering the window inoperative.To help avoid this problem make it a habit to operate all windows on a regular basis (weekly). In addition, all window weatherstrip/channels should be lubricated as prescribed during an Inspection I/II service.

Tech Tip - AC Operation

It’s hot outside! Your BMW’s AC is working hard to keep you cool. Unfortunately, our daily climate in Texas is considered a severe AC system duty area. AC systems are overworked and wear out sooner than expected. A few simple suggestions will help the AC system’s efficiency and longevity.

First, make sure the AC/Heat bias regulator dial, located in the center dash vent, is always on three blue dots.

Second, the AC system should be operated in the recirculation mode by pushing the recirculation button (circular arrow button without the ‘A’). This will close off the hot ambient air, normally allowed to infiltrate the cabin. If the air conditioner is allowed to cool just recirculated air, the cabin will cool down faster and ultimately be much cooler.

Third, the AC system programming is set at the factory to a normal setting for all North American cars. The AC system can be re-programmed to accept a new setting for “hot country” which will bias the AC system sensors, mixture flaps and air flow for maximum cooling.

Ideally, you should follow these steps to make the AC system as efficient as possible. The ultimate benefit will be an AC system that will be able to cycle off more frequently and therefore last longer without repair.

 

Tech Tip – Check Engine Light

As with a number of components in your BMW, the engine’s performance and operation is constantly being monitored. Depending on your BMW’s year and model, an engine problem will be brought to your attention via an indicator in the instrument cluster and will be displayed as one of the following:

• CHECK ENGINE

• SERVICE ENGINE SOON

• The Outline Symbol of an Engine

This indicator will always display when the car is first turned on to let you know it’s working. It should never be displayed when the engine is running. If it is, there is a potentially serious running problem that should not be ignored even if the car still starts and runs. Unfortunately, this telltale light will only come on after a problem has existed for a period of time. It is a last resort “cry for help” from the engine management system which can no longer substitute a value or compensate for the problem. The source of the problem must be diagnosed by starting with an interrogation of the engine management system to read out and interpret the stored faults.

 

Tech Tip - Clogged Body Drains

If you have an E34 (5 series from 1989-1995) and allow the cowling drains (those at the base of the windshield under the hood) to clog , expect soggy front footwell carpets after a hard rain as the water winds its way through the heater box seal and into the car. If this condition goes undetected your soggy carpets will not only mold, there is a good chance your air condition control unit and wiring will corrode and fail. Imagine a moldy, non-air conditioned car simply due to leaves in the cowling drains.

Tech Tip - Air Flow Blockage

Clogs present a different problem on all E39 (5-series from 96-03), here having to do with air conditioning and engine cooling. These cars tend to trap road debris in the lower air conditioner condenser area. Paper, leaves, and other road debris collect between the auxiliary fan and condenser causing a number of heat dissipation issues. The clogged condenser area creates super-heated air that affects radiator cooling, auxiliary fan operation, and eventually air conditioner compressor life. A good cleaning of the condenser once every couple of years will help alleviate these potentially expensive situations.

Tech Tip - Get your car ready fo summer

• Switch out your BMW’s engine oil & filter if it is needed (you should do this around every 3 months).

• Get a thorough tune-up from a professional BMW maintenance shop if necessary (check your BMW owner’s manual to see the frequency at which you should get a tune up).

• Look at and inspect the cooling system hoses for leaks, switch out engine coolant fluid if needed, and check drive belts for cracks or splits.

• Have a professional test your antifreeze. This prevents your coolant from boiling in the summer.

Recomended Care for BMW Convertible Tops

The best way to care for a cloth convertible soft top is with regular care, cleaning and maintenance. There are a “million” car care products out there but there are surprisingly few products for the care and maintenance of cloth soft tops like a BMW’s. BMWs were born in Europe and, in Europe, there is only ONE recommended product for caring for convertible tops. It is made by a company in the UK called Renovo. It is a safe, gentle but extremely effective line of products which are water-based and made specifically for expensive European cloth tops! The very first rule of soft top care is to  AVOID all products containing silicone or chemicals of any sort, and that is why Renovo is so strongly recommended as the only products to use! Not only are they completely safe for your soft top, they are completely safe for your car’s paint or clear coat and wipe off them easily if you get some on them. To care for you beautiful convertible’s gorgeous soft top, here’s the drill.

 

• Get a good scrub brush. Rub it across the back of your hand and if it doesn’t leave a welt or scratches – -  it is OK to use on your expensive top.

• Apply a good cleaner like Renovo Soft Top Canvas Cleaner according to instructions and scrub thoroughly. Rinse the foam and dirt off with a hose and let dry.