|Tough nuts to crack
Question : MY attempts to change the exhaust manifold
gasket on my Mazda 323 have failed as I am
unable to undo the nuts that secure the manifold to the cylinder head.
The nuts have rusted and I am afraid that I
may break something if I apply too much
force on them. It would be a simple job to
carry out otherwise.
I'd appreciate your advice on how I can
remove these stubborn nuts.
Answer : AS the manifold goes through heating and cooling cycles, the nuts will seize due to oxidation,
making them almost impossible to remove over
a period of time.
You are correct in saying that if too much
force was applied, the nuts may "round off" or,
worse, the manifold studs may snap off. In the
latter case, the cylinder head may have to be
removed, the remaining stud drilled out and
replaced. A "rounded" nut will have to be
Although not the perfect solution, you can
attempt liberally spraying the offending nut
with a commercially available lubricant, leaving
to soak in overnight.
In most cases, this should sufficiently soften
any rust allowing the nut to be undone with relative ease.