Loading ...This is the first in a series of articles designed to help you save money by showing you how to perform some basic inspections yourself. Not only will you save by not paying someone to perform the inspection, you’ll be able to identify potential issues/repairs before they become an expensive problem. In this article we address inspections you should perform under the hood. Future articles will cover brakes, exhaust, steering and suspension, etc..
These days, any chance to save a few bucks is a welcome opportunity. One area where all of us can save is in general vehicle inspections. You can save hundreds, even thousands, of dollars on inspections and services by simply spending a little personal time with your BMW or MINI.
Contrary to what BMW and the local dealer may want you to believe, the service and inspection reminders that your BMW will display occasionally do not mean “you must see a BMW dealer now or face catastrophic consequences.” These reminder lights are triggered by simple calculations using time, mileage, driving style and environmental inputs from the vehicle systems. We believe preventive maintenance should be performed more often than these reminders indicate. And we’re not alone – many BMW experts (including some you probably read in automotive publications) are of the opinion that the BMW maintenance schedule is inadequate. You can read our reasons and see our recommended maintenance schedule in the Winter 2008 issue of Fast Times.
Okay, let’s get going on our inspection. You won’t need any special tools for these under-the-hood checks, nor will you need to raise the car off the ground. (Note: the inspections outlined in future articles will require raising the vehicle off the ground. See the sidebar on hydraulic floor jacks and jack stands on page 7.) We’ll start with the easiest tasks and work forward.
To illustrate the typical locations of components, we’ve included photos of two BMW engine bays. Your particular BMW or MINI may look different or have components in a different location. We have shots of many engine bays (with component locations) on our web site: www.BavAuto.com/techinfo. For demonstrating the inspection procedures, we are using a 1990 325i and a 2004 330xi.1) Washer Fluid- If the washer fluid tank is visible (right), the fluid level is checked by just looking at the translucent tank. Some models (such as 5 series 97 thru 03) have a remote tank. In these cases, we must rely on the dashboard warning from the fluid level sensor. Add fluid through the reservoir filler cap. Add P21S Windshield Washer Fluid Booster for optimum windshield cleaning.
2) Power Steering Fluid- Check the fluid with the system warm. With engine off, remove the reservoir cap. If the cap has a dipstick, the fluid should be between the FULL and ADD marks on the dipstick. If
the reservoir cap does not have a dipstick, the fluid should be 10mm below the rim of the reservoir. Add fluid as required. All BMW systems will use either Dexron-III fluid (or Redline D4ATF), or 7.1 or 11s hydraulic fluid. Take note of the condition of the fluid in the reservoir: it should be bright translucent red (Dexron III and Redline) or clear, with perhaps a bit of a dark honey coloring (7.1 and 11s hydraulic fluid). If the fluid is dark and/or heavy, it should be changed. When changing the fluid, the filter should also be changed. The plastic reservoirs that have the caps with dipsticks have integral filters and the complete reservoir is replaced (under $40.00). Metal reservoirs have replaceable filters in the bottom of the reservoir. The power steering fluid and filter should be changed at 50,000 miles or 2 years.
3) Engine Oil- With engine off (for two minutes or more), remove the oil dipstick and wipe the indicator end with a rag. Reinsert the dipstick until fully seated. Withdraw the dipstick and check the oil level on the indicator end. The oil level should be between the FULL and ADD marks (the difference between the FULL and ADD marks is typically about one liter). Add oil if required. Take note of the visual condition of the oil. If the oil is dark honey colored, but still translucent on the dipstick, it is still serviceable (assuming the use of a “top-shelf” synthetic oil, such as the Lubro Moly synthetic motor oils). If the oil is thick and/or opaque (i.e. you can not see the dipstick through the oil), it’s time for a change. Note that while this is not a scientific method of determining oil change intervals, it is a good way to check for oil contamination.
4) Brake Fluid- Locate the brake fluid reservoir. Most models have the brake fluid reservoir openly accessible on the driver’s side, rear area of the engine compartment. (A couple of models are a bit trickier. For example, on 5 series 97 thru 03, the reservoir is under the driver’s side climate control/microfilter housing.) The brake fluid should be between the FULL and ADD marks on the side of the translucent fluid reservoir. Add DOT-4 or ATE Super brake fluid as required. Take note of the color of the fluid. Fresh DOT-4 brake fluid is clear, with a very slight amber tint; ATE Super is either bright blue or golden. If your brake fluid is dark, it’s time for a fluid flush and change. We recommend changing your brake fluid once a year.
5) Engine Coolant/Antifreeze- Some models have translucent coolant expansion tanks that have markings for HOT and COLD. You can simply view the coolant level through the tank. In these cases, the coolant should be between the HOT and COLD marks depending on the engine temperature. Some earlier models will have the filler cap directly on the radiator. In these instances, the fluid level is checked by removing the cap and seeing if the fluid is near the top of the cap flange. Most later models have solid colored expansion tanks or tanks in remote locations. In these cases, there will be a floating indicator (red stick) that, if the fluid level is correct, rises up out of the filler neck a bit when the cap is removed.
In instances, where the cap must be removed, follow this procedure: (Note: For safety, the engine must be fully cold!) Locate and carefully open the coolant cap by slightly loosening the cap and listening for any release of pressure. (It would not hurt to wrap a heavy rag around the cap, just in case there is pressure and/or hot fluid inside.) Once you are sure there is no excessive pressure, remove the cap and look inside the filler neck for fluid level (early cars) or look for the float to rise up. If the level looks low or the top of the float stays below the top of the filler neck, add coolant as required. Always add a mixture of 50% BMW coolant and 50% distilled water (unless you’re using waterless NPG+, which is used at full strength). This will give the best anti-corrosion protection. The “radiator fluid,” as it’s commonly called, performs multiple functions. It raises the boiling point of the engine coolant mixture (over that of plain water), lowers the freezing point (again, compared to plain water) and provides anti-corrosion protection for the internal coolant passages in the engine, radiator and heater system. When all things are operating properly, the engine coolant can become a neglected vital fluid. And, vital it is! If the coolant is any color other than clean, bright blue-ish (BMW coolant… others are different colors such as; green, yellow, orange, etc.), it should be flushed and changed. BMW coolant should be changed every three years; NPG+ coolant never needs changing.
6) Automatic Transmission Fluid -Most BMWs with automatic transmissions, up through the late ‘90s, have an under-hood transmission fluid dipstick. (If your BMW does not have an automatic transmission dipstick, we will cover the procedure when we get under the car for further inspections and services.) Check the fluid level with the transmission warm and the engine running. Remove the dipstick, wipe it clean and leave it out. With the parking brake engaged and your foot firmly on the brake pedal, run the shifter lever through the various positions from PARK, through all the gears, and back to PARK (hold in each position for a couple seconds). With the shifter in the PARK position and the engine still running, insert the dipstick all the way into the tube and then withdraw it. Read the fluid level and add if required. The difference between the FULL and ADD marks is typically about 1/2 liter. DO NOT OVER-FILL. On all models that have dipsticks, the fluid should be a bright and clear red color. If the fluid is cloudy or brownish, you should change both the fluid and the filter. We recommend fluid and filter changes at 50,000 miles or 2 years.
7) Accessory Drive Belts- The accessory drive belts operate the water pump, alternator, power steering pump and A/C compressor for most BMW models. Our BMWs can have two basic different accessory drive belt configurations; V-belt (not shown) and Serpentine belt (above). In a very general sense, most older models (early ‘90s and prior) have V-belt systems and most later models (early ‘90s and on) have serpentine belt systems. BMWs that use V-belts have a separate belt for each accessory (with the water pump and alternator on the same belt). Therefore, most BMWs that have V-belts will have three of them. On most BMWs with serpentine belt systems, the water pump, alternator, and power steering are run from one belt and the A/C compressor is run from another smaller belt. Inspect belts for visible fraying or cracking, on both the inside and outside surfaces of the belts. Listen to the belts as the engine is running. The belts should be quiet – there should be no squealing or squeaking. If you have a squeal or squeak noise, this may be due to a loose belt, a worn belt that has lost its original profile or a glazed belt that is slipping. Additionally, there may be a pulley with a worn bearing or one of the driven accessories may have failing bearings. With the engine off, check the belt tension by pushing down or pulling up in the middle. On a V-belt system, the belts should have about 1/2” of total play. Each driven accessory will have a mechanical provision for tensioning the belt. (Refer to a repair manual for tensioning procedures.) On serpentine systems, the belt should be quite taut. If it is not, the belt tensioner might need to be replaced (there is no adjustment you can do). If the belts are taut and you still have squealing, use a mechanic’s stethoscope (part #52750) with a megaphone end to localize the source of the sound. All accessory drive belts (and tensioners and pulleys on serpentine systems) should be replaced at 60,000 miles or 4 years.
8.) Water Pump and Fan Clutch- With the engine off, grasp the engine fan (or water pump pulley, if there is no engine driven fan) and try to wobble it side-to-side or front to rear. Other than slight deflection of the blades, there should be no movement. If a wobble is detected, look closely to see if the movement is between the fan (and fan clutch) and the water pump pulley, or between the water pump pulley and the pump housing (behind the pulley). If there is movement between the fan/clutch assembly and the pulley, the fan clutch must be replaced. If there is movement between the pulley and the water pump housing, replace the water pump. Failure to replace a worn fan clutch or water pump can result in breakage of the shaft or bearings and collateral damage of belts, hoses, fan, radiator, etc.. It could leave you stranded, too. We strongly recommend preventative maintenance replacement of the water pump and the fan clutch at 60,000–100,000 miles, depending on your model (See Otto’s Ultimate Maintenance Schedule in the Winter 2008 of Fast Times issue at www.BavAuto.com/newsletter. While you’re there, also see the Spring 2007 issue, in which we tell you how to replace a BMW water pump.)
9) Coolant Hoses- Before checking these, the engine and coolant system should be cool to the touch. Inspect coolant hoses for bulges, especially at hose clamps or quick-connect fittings. Also check for soft sections (they will be very easy to squeeze), cuts in the hoses at hose clamps/fittings and any evidence of a current or past coolant leak. Additionally, if you choose to, you can disconnect one of the upper main hoses and inspect the interior of the hose. Look for corrosion deposits, cuts, swelling or any other issues. Replace any hoses that are suspect. If your car uses hose clamps, do not re-use the existing ones – get fresh hose clamps with curled edges that won’t cut the rubber like the straight, sharp edges on ordinary clamps (see below). Later-model BMWs use quick-connect fittings instead of hose clamps. Replace all hoses and clamps at 60,000 miles or 4 years.
10) Engine Air Filter- Remove the filter and inspect both sides. The inlet side will likely be loaded with dirt, twigs, insects, etc. (depending on how recently it was changed). If its heavily loaded with contaminants, replace it. You should also inspect the air filter’s perimeter sealing lip. If cracked, torn or otherwise damaged, replace the filter. You can also remove the air filter housing (typically very easy) and clean it out. We recommend air filter replacement at 15,000 miles or once a year (more often in dirtier conditions).
11) Cabin Climate System Microfilter Remove and inspect the microfilter(s). (We show you how to do this in the Summer 2003 issue, which you can find at www.BavAuto.com/newsletter.) Note that the microfilters for 3 series 92 through 98, 5 series 89 through 96 and 7 series 88 through 94 are accessed from the interior passenger compartment. All others are accessed under the hood. Some models have two microfilters. Inspect the filter(s) for contaminants. If heavily loaded, replace the filter(s). We recommend microfilter replacement once a year (more often if inspection shows heavy contamination).
12) Ignition System- Older BMWs have coils, distributor caps, spark plug wires, etc.. Newer BMWs have “coil-on-plug” ignition systems, which have spark plugs, coils, and spark plug connectors. Let’s consider the older BMW models first:
Remove the distributor cap to inspect the electrical contacts for excessive pitting and burning, as well as any signs of cracking or carbon tracking (thin lines that look like cracks, leading to the edge of the cap). Any of these conditions indicate replacement is needed. While the cap is off, inspect the rotor in the same way. Visually inspect the spark plug wires for cracking at the connector boots or in the wires themselves. Additionally, a heavy coating of grime can induce misfires. Replace the spark plug wire set if you find the boots or wires are cracked or deteriorating. Inspect the ignition coil for cracks or carbon tracking at the connector end of the coil (remove the high tension lead to inspect fully). Replace the coil if any of these conditions are found.
On newer models with coil-on-plug ignition systems, remove the plastic trim cover(s) to expose the individual coils. Unbolt the coils and pull them and the rubber connector boots out. Inspect the coils for any signs of overheating or cracking. Replace any coils that show these signs. (This would be a great time to upgrade to our high-performance ignition coils. See them at www.BavAuto.com.) Inspect the rubber connector boots for signs of deterioration, cracking or burning (arcing). Replace the boots as required. If the boots show any oil, the valve cover gaskets are leaking and should be replaced, as well as the boots.
Now let’s turn our attention to the spark plugs. Remove at least one spark plug and inspect the “business end.” If the base of the spark plug body (the metal area below the insulator) is covered in oil, this indicates the valve cover gasket needs replacing. When inspecting the actual electrode end of the plug, excessive deposits of any type are a sign that the plugs should be replaced. Normal plug condition will show a bit of tan/white coloring with the electrodes being fairly sharp (not rounded). If the plug shows black deposits, this indicates the engine is using excessive fuel (firm, dry deposits) or oil (looser, shiny or wet deposits). The plugs should be replaced. If the spark plug electrode gap (if applicable) is wider than specified, this is typically due to normal wear and the plugs should be replaced. For replacement intervals for ignition system components, see Bavarian Otto’s Ultimate Maintenance Schedule in the Winter 2008 Fast Times at www.BavAuto.com/newsletter.)
