TIMING BELTS 
TIMING BELTS
Don't let this very important service go untended! Most cars today using rubber timing belts to turn the camshaft(s) and operate the valves in sequence with the crankshaft. These belts must be replaced at an interval of mileage or time (whichever occurs first) that is recommended by the car's manufacturer.
Almost all cars today have what is called "and interference valvetrain". In other words, if the cam to crank timing (maintained by the timing belt) falls out of a very narrow range, the valves and pistons interfere with each other, resulting in VERY expensive damage.
Some examples of recommended change intervals:
- BMW
- 528e, 325, 325e, i, is and convertible through 92/93 = 50K or 4 years
- Models after 93 have no chains with no intervals
- Audi
- All models = 60K or 5 years (Some older models = 90K)
- VW
- All VW models except VR6 engines = 60K or 4 years
- Porsche
- 944 models 83 thru ... 924S, 87 & 88 = 30K or 4 years
- 944S, 944S2 and 968 = 45K or 4 years
WATER PUMPS
WATER PUMPS
When you replace your timing belt, replace the water pump at the same time.
Doing so will save you time and money down the road. Although newer BMW's have timing chains, many have water pumps with plastic impellers. These should be checked and replaced with the thermostat every 4-5 years.
Some examples of car makes and models that will require periodic water pump replacement:
- BMW
- 528e, 325, 325e, i, is and convertible through 92/93 = 50K or 4 years
- Audi
- All models = 60K or 4 years (Some older models = 90K)
- VW
- All VW models except VR6 engines 60K or 4 years
- Porsche
- 944 models 83 thru ... 924S, 87 & 88 = 30K or 4 years
- 944S, 944S2 and 968 = 45K or 4 years
RADIATORS
RADIATORS
The radiators found in today's cars are composed partly of plastic. Over time, the expansion tank, or possibly the fittings, will break.
While there are repair kits for the plastic tanks, the repair usually does not last long, and you will need to replace the radiator.
Some examples of car makes and models that will require periodic checking of the radiator.
- BMW
- All models since 1992.
- Audi
- All models with aluminum & plastic radiators.
- VW
- All VW's with aluminum & plastic radiators.
- Porsche
- All 944. 968. and 928 models.