Running

Technical Information and Restoration Parts for the 928

Running Test - (Max 300 Points)

	Cold Start - The engine should be started cold with no detectable heat. Sometimes this is not possible, but the importance of hearing an engine when cold can not be over stated. Many engine problems can be detected early such as bad lifters, rod knocks and sticky valves by listening to an engine when it is cold. After the oil has had a chance to circulate these noises will quiet down. When starting the engine should crank over strongly and start within the first few revolutions. The engine should not make any clicking sounds or blow smoke. It should run smooth at an advanced idle and slowly settle down to about 700 RPM's when warm. (Deduct 20 points for cold start problem)
	Warm Up - Once started let the engine run at idle for the rest of the inspection. The temperature gauge should stay below the mid mark and the auxiliary cooling fan on the pre-87 models should not come on unless it is an unusually hot day. If the electric fans come on they should cycle off in a very short time (thirty seconds to a minute) On the S4 model if the flaps have not been modified to stay open all the time they should slowly open as the car is warms up. Once at operating temperature the flaps should stay open. (If the car overheats during the inspection deduct 50 points)
	Listen for noises. The engine should be quiet. A hose can be detect the source of noises. (Do not get the hose caught in any of the moving parts). The major sources of noises are. Smog pump - (Deduct 4 points) Alternator - (Deduct 5 points pre 1985 - 15 points 85+) Power Steering Pump (Deduct 5 points) Fan Belts - Check wear - (Deduct 1 point for worn belts) Injectors - A little clicking is normal Water Pump - (Deduct 20 points) Electric Fans - (Deduct 5 points for each one bad) Loose parts rattling (Access repair costs) Clicking valves (When cold - 15 points - when warn 30 points) Knocks (Deduct 150 Points)
	Smoking - When the engine is idling or even under acceleration - warm or cold the engine should not smoke. Excess smoke can mean worn rings, bad valves guides or a faulty injection system. White smoke indicates water entering the combustion chamber suggesting a blown head gasket or a cracked head. (Deduct 150 points for excess smoking)
	Compression test - It is not always possible to conduct a compression test in all sales situation. A compression test should be conducted on a warm engine. The aluminum block and pistons do not seat as well when cold and can give erroneous readings. Disconnect power to the coil(s) and pull the fuel pump relay to disable the fuel system. The first test should be run dry, the second with oil. The wet test should show very consistent measurements between cylinders - less than 10 pound variation. [add info for valve timing issue on 32 valve engines.] ( (Deduct from 75 for each bank with bad compression)

Leaks

The design of the aluminum engine combined with long idle periods create the perfect conditions for oil leaks. It is not uncommon for a 928 to have more then one oil leak. A careful inspection of the area where the car is stored is worthwhile.

Oil Leaks - While the engine is running check for leaks. Before staring the car place a clean piece of cardboard under the engine. If you can smell a burning from the engine or see smoke coming off the exhaust manifolds then the engine is leaking oil. Check the most common places for leaks as follows:

Cam Covers - The cam covers are a common place for leaks either at the back of the covers or on the lower edges. (Deduct 5 points for each cover that is leaking)

Oil Cooler Hoses - The oil cooler hoses on the left side of the engine often leak at the crimps joints both at the engine and on entering the radiator. A rag can be used to clean and dry the joints. New oil appearing indicates the hose is bad. (Deduct 7 points for each hose that is leaking)

Oil Pan - The oil pan is a very common area for leaks. The oil pan gasket crushes over time causing the oil pan bolts to come loose. (Deduct 10 points for a leaking oil pan gasket)

Front and Rear Seals - Each end of the crankshaft has a rubber seal that prevents oil from leaking. Over time these seals can dry out. While it is difficult to see oil coming from the seals, the cardboard can help isolate these leaks. (Deduct 30 points for each leaking seal)

Exhaust System - Listen at the tail pipe for skips or exhaust leaks. Cover the tail pipes with a rag to check for leak in the exhaust system. (Deduct 5 points for minor leaks and 5 points for each bad component.)