Engine Maintenance (before August 1985) (Audi 100 C3)

Every 15,000 km of mileage it is necessary:

1. Check the tightness of the cooling system and the condition of the hoses. If a coolant leak is detected, tighten the hose clamps. If cracks or tears are found on the hoses, or if the rubber has lost elasticity, replace the hoses. Check the coolant level and top up to normal if necessary. Check the density of the coolant and top up with concentrate if necessary.

2. Check and, if necessary, adjust the tension of the auxiliary drive belt (generator, power steering pump, etc.).

3. Check the tightness of the lubrication system. If oil leaks are detected, tighten the fastening of the lubrication system units.

4. Replace the oil in the engine crankcase and the oil filter.

5. Check the fuel system for leaks and the condition of the hoses. If fuel is leaking, tighten the nuts, fittings and hose clamps. Replace hoses that have cracks, tears or if the rubber has lost its elasticity.

6. Check and, if necessary, adjust the idle speed of the crankshaft and the content of carbon monoxide (CO) and hydrocarbons (CH) in the exhaust gases.

7. Replace the spark plugs. Clean the high-voltage wires and spark plug tips from dust and dirt.

8. Adjust the valve clearances (for engines without hydraulic tappets). Replace the cylinder head cover gasket.

9. Replace the fuel filter.

10. Replace the air filter element.

11. For diesel engines, check and, if necessary, adjust the tension of the camshaft drive belt.

12. Check the compression in the engine cylinders.

13. Check the exhaust system for leaks.

Every 30,000 km, perform all the work that is supposed to be performed after 15,000 km, and, in addition, replace the auxiliary drive belt.

[The original article is posted on the resource AUDImanual]