Mercruiser 470 Warped Block/Head
 

So i just replaced my head gasket on my '78 Mercruiser 470. Noticed the old one looked undamaged. Now that the new one is installed, the engine is still leaking around the head gasket and runnin hot. I think either the head or block might be warped. Anyone know whether either is a common problem? And does anybody out there have anything to say about the pour-in sealers aka Blue Devil, Steel Seal, etc? Any opinions are welcome and appreciated... Thanks!

Pull the head, take it to a machine shop and have them check it. They can either fly cut it if it's aluminum or surface grind it if it's cast iron... If it's really warped then it's time for a new head. When you reinstall the head, ignore the recommended torque pattern and start tightening the bolts where the warp was first, then work out to the ends. I doubt very seriously that the block is warped.. it takes a LOT of heat to warp a cast iron block. I'm not a fan of sealers, because I always worry about them clogging the engine, but I've seen them seal freeze out plugs and small cracks, so they do work. If you go that route I'd recommend K-Seal made by Solv-Tec. It's used in industrial applications, Trucks, Tractors, AG, RV and Larger capicity engines. Seems to work good... We've used it on a few of our Cat Excavators with great results.

Thanks for the advice on the sealer... The block on the merc 470 is aluminum and the head is cast iron. This is what is making me lean toward the sealer-I'm afraid that the aluminum block would soften and warp before the head, and removing the block is a pretty big job. Several mechanics have told me NOT to put money in the engine because they are so problematic and expensive to fix. I figure if I can throw some sealer in it and get a few years outta the engine I'll be happy. Repower it later when i win the lottery.

have the head checked by a machine shop, use a merc or FelPro(they used to make them) gasket, tourque the gasket per spec in three stages. retorque after first heat cycle, shoudl be good to go. BTW, while the head is off the engine, lay a straight edge across the block to check if its warped

thanks for the advice. any opinions on using some kind of sealant around the head gasket during installation?