Rear main cap sealant
 

Rear main cap sealant on 1998 454 mag gen 6 I was told using sealant on the rear main cap mating surfaces (cap to block) would be a good idea to prevent an oil leak my mercruiser manual makes no mention of this any of you guys building gen 6 bbc using sealant on the rear main cap?

you'd use something like loc-tite gasket maker 515, which is an anaerobic sealant on main or OHC caps which are exposed to the outside of the engine. but looking at pics of the seal and main cap, i think you'd just put a dab of black rtv where the seal mates with the other half of the seal. if you had a one-piece seal i'd recommend the 515

yep like mentioned...510...515 and 518 will also work but 510 works best..it only drt's if ite clamped between the 2 metals..make sure the surface's are dry and oil free..

So is the sealant required or am i ok by not using it on this engine?

if you want a leak dont use it,,i use it no matter ir it needed it or not..with all the hot cold expansion i would use it..all you need is a ski, coat and once it compress's it will seal,,510 stays like jelly until you clamp down on it..

Please what ever you do (I use RTV black on the cap) don't forget the little "O" ring between the cap and the block. If you do ..... boom!

Thanks guys i will use the sealant and yes o ring was installed thanks again for all the advice and happy boating