If, from the time the vehicle is new, the routine maintenance schedule is followed closely and frequent checks are made of fluid levels and high wear items, as suggested throughout this manual, the engine will be kept in relatively good running condition and the need for additional work will be minimised.

It is possible that there will be times when the engine is running poorly due to the lack of regular maintenance. This is even more likely if a used vehicle, which has not received regular and frequent maintenance checks, is purchased. In such cases, additional work may need to be carried out, outside of the regular maintenance intervals.

If engine wear is suspected, a compression test will provide valuable information regarding the overall performance of the main internal components. Such a test can be used as a basis to decide on the extent of the work to be carried out. If for example a compression test indicates serious internal engine wear, conventional maintenance as described in this Chapter will not greatly improve the performance of the engine, and may prove a waste of time and money, unless extensive overhaul work is carried out first.

The following series of operations are those most often required to improve the performance of a generally poor-running engine.

a) Clean, inspect and test the battery (Section 5).

b) Check the levels of all the engine related fluids (Section 3).

c) Check the condition and tension of the alternator drivebelt (Section 20).

d) Check the condition of the spark plugs and renew if necessary (Section 15).

e) Check the condition of the air cleaner element, and renew if necessary (Sec- tion 34).

f) Check the condition of all hoses and check for fluid leaks.

g) Check and if necessary adjust the idle speed (where possible) (Section 10).