It’s Always the Little Things

By Mike Perkins
BMW CCA/Houston Chapter Technical Advisor
Owner – Bavarian Machine Specialties

When I first started in business a friend, worried about my stress level, took me aside and told me: “Don’t sweat the small stuff.” Over the last twenty-five years I have learned that his advice was simply wrong. From my experience, if you don’t sweat the small stuff you will soon be sweating much bigger problems. Like a row of dominos, seemingly little car problems have a way of compounding themselves into major system or reliability issues. With just a little bit of attention, caring for some of the following “little” issues will keep you from having bigger problems.

Clogged Body Drains

An easily preventable problem centers on clogged body drains (the small drains that allow rain and carwash-water an escape from the body). Drains in the cowling area, sunroof, and convertible top storage compartment are seldom inspected and without attention they can lead to a major calamity. Those who park outside, especially under trees, beware: leaves and debris are easily trapped in key drainage areas, and if allowed to decompose, will completely clog the drains.

If you 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.

Clogged cowling drains also can flood the passenger footwell area, the water instead flows to the area housing the engine management control unit (DME) which, at best, causes a non-start condition until the unit dries (or at worst a totally “fried” DME). Perhaps you or one of your friends have experienced a non-start after running your 3-series through a car wash (check those cowling drains).

Surprisingly, sunroof drains are notorious for clogs. A clogged sunroof drain leads to soaked headliners and or ruined leather seats. A quick check of the drains can be performed by pouring a small cup of water into first one corner, then the other corners of the sunroof channel. If clear, you will see the water pool beneath the car behind both the front and rear wheels. If you find a clogged drain be careful using compressed air to clean the blockage: sunroof vent tubes are pressed-on to plastic tubes that can pop off if the clog is stubborn.
Clogged drains in the convertible-top storage areas of some cars are also problematic. One customer of ours regularly parks beneath a Live Oak Tree. After a week out of town (when it rained heavily) he returned to find a thoroughly soaked back seat and two inches of standing water in the footwells. Initially he thought the convertible top leaked, but upon inspection the culprits were completely clogged drains in the convertible top storage area. As the storage compartment filled with water it overflowed into the backseat and onto the floor.

Air Flow Blockage

Clogs present a different problem having to do with air conditioning and engine cooling. Some 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.

Paper, leaves and other road debris cause problems with some BMW’s that have an alternator cooling duct (especially those with low inlets). Pop the plastic cover off the back of the alternator some time and you will think some rodent built a nest in your alternator. We have found all manner of paper, twigs, leaves, feathers, and even cigarette butts crammed into the back of the alternator. The ducting acts to cool the alternator’s diode plate and is needed especially on later model cars with higher amperage alternators. Heat build up has become such an issue that BMW engineers have tried water cooling the alternator. Unfortunately, in my experience the only time the alternator cooling duct is cleaned is after an alternator failure and the expensive new alternator is installed.

One final clogging problem for now: As everyone knows, the most efficient way to operate the air conditioning system in the hot, humid Houston climate is in recirculation mode. However, be aware that on some cars this can lead to a clogging problem with the integrated heating and air conditioning system (IHKA) internal recirculation filters. These IHKA filters are not to be confused with the external-air micro filters (which should be replaced at regular intervals as part of routine service). When these internal IHKA filters become clogged they impede air flow through the air conditioning system including the blower motor and final stage If no attention is paid to the IHKA filters the result will be a 12-hour job to remove the dash and replace a burnt out blower – all for the sake of two small filters. When you replace these original filters for the first time, especially if you have a pet that travels in the car, wear a mask and gloves because it won’t be pretty. You won’t believe what you’ve been breathing

Engine Cooling System

Engine cooling systems can present a host of little problems that, when not properly addressed, can lead to an expensive failure. One such problem that stands out in my experience has to do with the lack of concern for the corrosion of aluminum parts, especially where oxygen may come in contact with coolant. The perfect breeding ground for this kind of corrosion is at the mating surface on the cylinder head for the thermostat housing. Time and again I have encountered coolant seepage at the thermostat housing only six months following a thermostat or thermostat-housing replacement because no attention was paid to the “minor” corrosion under the profile gasket. This corrosion may look innocent enough in the early stages but by the time the corrosion has festered, you will end up with a pitted aluminum cylinder head that cannot be sealed by normal means. Removing the head for welding repairs is an extreme measure we have had to take, all for the lack of a little extra effort during the initial repair.

Engine Oil Service

Have you had the opportunity to see inside a motor serviced under the current BMW factory recommended maintenance program? An internal coating of sludge will be found inside a 45,000-mile engine which has received only the recommended two oil changes. Changing oil more often is seemingly such a little thing but it has so many benefits for the longevity of your car’s motor. The valve train, especially hydraulic lifters, cannot survive in such a filthy environment. How many of you have heard that tell-tale tick, tick, tick on start up? Noisy lifters are directly related to the internal cleanliness of the engine. Just because BMW only pays for one oil change every 15,000 miles, don’t believe that is everything you need – common sense can prevail.

This is just the tip of the iceberg when it comes to my list of “little” things that, without regular attention, can lead to costly and potentially disabling repairs. Yes, what is here will help prevent future problems but more importantly, it helps to point-out the benefits of tackling the “little” things now, rather than paying for expensive crisis management later. As another friend of told me: “An ounce of prevention is…..” well, you know the rest.