a thus the exhaust manifold which may be formed in part from a cover plate that may be formed from a material other than that of the cylinder block i e the plate 88 will be subject to galvanic protection the construction of the anode 91 may be the same as those associated with the cylinder head 39 and which will now be described by primary reference to fig1 12 wherein a first embodiment thereof is depicted these corrosion protection anodes are indicated generally by the reference numeral 92 and are adapted to be mounted in clean out openings 93 formed in the cylinder head 39 in communication with its cooling jacket portions d the cylinder head is formed with a counter bored opening 94 above the clean out opening 93 and which receives a seal indicated generally by the reference numeral 95 this seal 95 has a generally cylindrical body portion 95 from which a rib 96 extends the anode member 92 includes a mounting part 97 that has a downwardly extending portion 98 that engages the seal 95 and urges it into engagement with a shoulder 98 formed at the end of the counter bore 94 this causes the rib 96 to move into tight sealing engagement with an anode element 99 that is fixed to the closure member 97 by means of a threaded fastener 101 thus a watertight seal is provided on one which permits the anode assembly 92 to be replaced when the highly reactive anode element 99 corrodes away thus good servicing is easily assured and good.