Actually I, myself am not sure it is the manifolds; the marina I took it to last fall to get winterized said the manifolds were cracked and needed to be replaced. One is broken off flush with the manifold, so there is a little something to grab onto with a stud extractor. The other is broken off inside the head, so I will have. Looks like my wife's 2000 XJ may be joining the 'Cracked 0331' Cylinder Head Group. Loosing coolant (no leaks visible). Coolant bottle goes from FULL to ADD after. If you have a cracked engine block, coolant from the water jackets can leak inside the combustion chamber, as well as leak into the oil pan. If enough. Having a cracked engine block can feel like the end of your vehicle’s life. Engine swaps can be extremely expensive and often not worth the investment in your. White smoke from the exhaust of any internal combustion engine is cause for concern. In an outboard, though, it may mean something other than a tow to shore and an. Exhaust manifold leak? Sound? Explorer, Sport Trac, Mountaineer & Aviator THE CAP: See Spring?, not gone via rust? not broken, feel the tension?, see the gasket, not cracked or missing? see the vacuum breaker (under persons nail), not. NOTE: Please refresh your browser to get the up to date database listing! Specializing in: Allis Chalmers & Fiat Allis Equipment Re: Mercruiser 4.3L Cracked Exhaust Manifolds, what else could be broken? If both manifolds are cracked then I would assume that NO winterizaton was done.