is more likely to need renewing than the gasket on the
, because of the greater damage caused to the
by heat; but the procedure is much the same for both.
A 'blown' exhaust gasket can be detected by excessive noise from the exhaust, and by white burn marks around the
The intake and exhaust manifolds may be on opposite sides of the
, or they may be combined or bolted close together.
has a V-configuration, there will be exhaust manifolds on the outer side of each
bank, but probably just one intake manifold located in the centre of the V.
to all nuts or bolts which have to be undone, including the
When the nuts or bolts are removed, the remains of the old gasket may cause the manifold to stick: tap the manifold with a rawhide hammer to loosen it. If any manifold
are broken or damaged, remove them using self-locking grips, two nuts and a spanner, or stud remover .
With the manifold off, carefully scrape all gasket-mounting surfaces clean of dirt and bits of the old gasket. Do not allow particles to fall into the manifold or the cylinder head.
Check the manifold to see that it is not cracked or damaged; check its face with a straight edge — such as a steel ruler — to see that it is not warped. If it is, replace it.
a new gasket, making sure that it is the right way round, with all holes lined up. On some
a gasket may be in two or three pieces, or inserts may be fitted; be sure all parts are properly aligned.
Some water-heated intake manifolds, particularly on
, require gasket
on each side of the gasket, because the larger water passages are more prone to leakage.
Reassembly is in the reverse order of removal. Tighten the nuts on the manifold, using a
adjusted to the setting recommended in the car service manual. The tightening sequence is usually from the centre of the manifold outwards to the ends.
After reassembly, run the engine to working temperature,
it off and check the
Removing the inlet-manifold gasket
. Make a careful note of all the connections to the
Disconnect the choke and throttle cables to the
. Then take off the
If possible, keep the disconnected end of the fuel pipe higher than the level of fuel in the
If the end of the pipe is lower than the fuel level, plug it with a pencil stub or a small bung.
If the carburettor has an
choke, disconnect the water pipes or wires at the choke.
Disconnect the pipes or
from the intake manifold. Disconnect the
pipe if fitted.
Remove the manifold and replace the gasket.
If the manifold is water-heated, and particularly if it is on a V-engine, check with your local dealer or with a service manual to see whether gasket sealant should be used on both sides of the gasket.
Reassembly is the reverse order of removal. When reassembly is complete, top up the car cooling system, run the engine up to working temperature and check that there are no leaks.
Removing the exhaust-manifold gasket
Check that there will be enough movement at the front end of the exhaust pipe to allow removal of the manifold.
If there is not, remove any exhaust-bracket connections on the engine or gearbox housing. Remove any other components which may be in the way.
Undo the clamp holding the exhaust pipe to the manifold. If the clamp has a gasket, fit a new one during reassembly.
Unscrew the manifold nuts or bolts. If there is a
fitted, remove it. Take off the manifold and renew the gasket.
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Gaskets and oil seals should be replaced if worn or leaking, or whenever removed during servicing. Replacement is simple, but some engine dismantling may be necessary to reach them. Buy gasket sets from a dealer for the make of car, and state clearly for what parts they are needed.