If an exhaust man ifo~d gasket leaks—usually because a nut or bolt has worked loose— exhaust fumes may drift into the car.

A leak makes a distinct chuffing sound and the hot, escaping gas can befeltwith the palm of the hand. Renew- ing the gasket cures the trouble.

A few cars have a combined inlet and exhaust manifold. On these the carburettor air cleaner must be taken off, and it may be necessary to discon - nect the throttle and choke con- trols at the carburettor if they are anchored to the manifold.

Step 1. If the manifold has never been removed, put penetrating oil on the fixing bolts or nuts and leave it over- night to work into the threads.

2. Remove the nuts or bolts securing the manifold, using a socket and extension or a box spanner, if necessary.

3. Move the manifold away from the cylinder head and extract the old gasket. On a few cars, the downpipe to the exhaust system will restrict movement of the manifold, On these, loosen the clamp be- tween manifold and downpipe.

4. Scrape off all traces of old gasket material from the man i- fold and head faces.

5. Insert the new gasket, refit the manifold and do up all fixings finger-tight. Then tighten them firmly with a spanner or socket, working outwards from the centre.

6. If the downpipe joint has been loosened, re-tighten the fixings. Reconnect throttle and choke controls, and refit the air cleaner if it has been removed.