Bellevue Auto Repair

Who is affected?

Any and every BMW 318 with an M42 (16 valve twin-cam 4-cylinder) engine built prior to 11/93. This includes the E30 chassis sold as a 1991 model and 1992-1994 E36 chassis models.

What is the problem?

A rubberized gasket (officially known as the “Timing Case Profile Gasket”, often incorrectly referred to as the Head Gasket) measuring approximately 10 inches long and approximately 1.5 inches high that resides between the cylinder head and timing case is defective. I hesitate to put any exact statistics on it, but this gasket is failing at an EXTREMELY HIGH rate. I would guess a 95-97% failure rate. When it fails, coolant leaks from the engine into the engine compartment, usually near the vicinity of the passenger side of the steering rack/onto the AC compressor/onto the ground.

When does this occur?

*average* failure appears to be between 68,000 miles and 77,000 miles. Some of these gaskets gradually deteriorate, leaving telltale drops of coolant on garage floors, while there have been documented cases of others failing suddenly, leaving cars overheated, stalled, and slick coolant all over road surfaces. NOT good.

Why does this occur?

According to BMW Technical Service Bulletin Number 11 10 93 (3885) dated 11/93, the Timing Case Profile Gaskets fail due to inferior/defective rubber used in the manufacture of the actual gasket. Cars built after 10/93 have Timing Case Profile Gaskets made with “an optimized rubber material composition”.

How is the repair done?

Removal of the cylinder head is necessary for repair. This is very labor intensive, once the head is off, its simply a matter of scraping/removing the old gasket off, repairing any pitting of the metal surfaces using a JB Weld type compound, allowing ample time for the JB Weld to dry, then installing a new/improved gasket.

We continue to see problems due to water pump failures on the M50 and M52 engines. These engines were first introduced in 1992 in the 325s and 525s. Early engines have a plastic fan blade impeller pressed onto a metal shaft that is turned by the pulley and fan belt. The impeller pumps, coolant throughout your engine and it is essential that it operates at peak efficiency. Over time, the plastic cracks and the pump impeller freewheels and/or comes off the shaft. The result is a temperature gauge reading in the red…HOT! If this happens to you…turn off your engine and call a tow truck unless you’re in danger. Otherwise, at a minimum, you will either blow a head gasket and/or warp your cylinder head. Very expensive. Older water pumps tend to always leak when they’ve failed; however, these pumps don’t leak very often. Unless the technician knows this, he will usually recommend a new radiator, only to find the same overheating problem still exists after the new radiator is installed. The solution is to replace the water pump with a new one with a metal impeller. Although the part number is the same for early plastic impeller pumps and the late ones (11 51 1 433 828), the newer ones have a metal impeller and are more reliable. Insist on a metal impeller if you need a pump..

There is another cooling problem we see regularly on the same engines…namely a broken thermostat which manifests itself by requiring an extended warm-up time. Most of the time, the engine never reaches proper operating temperature. Upon removal from the engine, we usually find the straps that hold the thermostat together have separated from the body of the thermostat and the thermostat is always open. This condition can cause plug fouling due to the fact that the coolant temperature sensor senses the coolant as being in a start-up mode (cold) and richens the fuel/air mixture. Eventually, damage to and replacement of your spark plugs and oxygen sensor will be inevitable. Now for the worst news…BMW continues to install plastic impeller water pumps in their new cars, despite a high failure rate. So if you have a 318, 325, 328, 525 or 528 built since 1992, your water pump may be faulty. Curiously, all of the replacement water pumps which BMW sells are made with metal impellers which tend to be very durable. So what should you do? Have your car checked if you experience any cooling system problems, whether overheating or running too cool. As a rule of thumb, we recommend that a water pump be replaced if it is an original with over 60,000 miles. We would rather be safe than sorry. .

We get frequent complaints from E30 and even some E36 (1984 and later 3-series) about a “clunk” from the rear of their cars that happens when they go over a slight bump or rise. The problem is usually the rear upper shock bushings separating. The cure is to replace those bushings Trunk switch problem. The new 5-series model E39 has had a problem with opening trunk doors. People assume the trunk door is secured by a mechanical latch that would require a hefty push to open. That’s not the case. The trunks on the new 5-series are operated by an electrical switch which does not require you apply special force to activate. In fact, that has become the problem – people punch the switch so hard that the switch mechanism becomes pushed back into the trunk area and therefore becomes inoperative. BMW has now developed a better- designed switch panel which prevents it from being pushed inside the trunk. Meanwhile, go easy on the trunk switch and shouldn’t have a problem.

The smell from the A/C system is from bacteria on the evaporator. For the same reason one puts distilled water in cigar humidors and room humidifiers to avoid this, there’s bacteria in the condensation that forms on the evaporator.

We, as do all experts, recommend flushing your Audi, BMW, or Mercedes-Benz brake fluid annually. This is an important maintenance service do to the fact brake fluid is hygroscopic which means your brake fluid absorbs water ( moisture ) from the air. Yes, your reservoir is tightly capped but the laws of physics require it be vented to atmosphere. There in lies the problem. This moisture not only lowers the fluids boiling point, leading to a spongy brake pedal on frequent or long hard stops, but if unchecked will lead to expensive corrosion damage to all the systems metal parts! Note!! We DO NOT recommend replacement with silicone based brake fluid! Unless you are driving your car extensively at the track and have completely disassembled the system and purged all lines, valves and ABS hydraulic unit, some mineral fluid will remain in pockets. The two fluids do not mix! Besides the corrosion problem, these pockets have a much lower boiling point, usually in the calipers where heat is most concentrated ! i.e., unexpected lose in brake pedal feel and dangerous increase in stopping distance!