Is anyone out there aware of a common problem on Ford 460 engines with exhaust manifolds? I had my 1990 motor home (45,000 miles) sold until the prospective buyer brought a Ford Service Manager to inspect it. He said the exhaust manifolds were leaking (no doubt true) and that a small piece was broken off at one corner of one of them. He went on to say that they are a nightmare to change, because the bolts usually break off, in turn requiring drilling out the broken bolts and installing helicoils, or, at worst, requiring replacement of the cylinder heads. He also said, after all of the work is completed to replace the manifolds and the gaskets, they will likely start to leak again in as little as 10,000 miles. He said the only permanent solution is to install a Banks system, or, at the very least, go to 3.5 - 4 inch diameter exhaust beginning at the point that the exhaust from both sides combines into one pipe. (He also said this problem has NOT been resolved by Ford, and that the V-10s are prone to the same problems, because they, too, funnel the exhaust from 2-inch pipes on each side into a single 2 pipe and exhaust system, and this creates too much heat. He said the GM 454s are bad for this too. And he put the icing on the cake when he said it would not pass a government safety check (required to transfer ownership in Ontario) as it was. Result: I lost the sale! Has anyone else heard of this common problem? Are there any recommendations for solution? If this guy is correct, it sounds like ANYONE would be nuts to buy a gas-powered motor home! Please reply to the group if you have any comments or suggestions. Thanks.

Is anyone out there aware of a common problem on Ford 460 engines with exhaust manifolds? I had my 1990 motor home (45,000 miles) sold until the prospective buyer brought a Ford Service Manager to inspect it. He said the exhaust manifolds were leaking (no doubt true) and that a small piece was broken off at one corner of one of them. He went on to say that they are a nightmare to change, because the bolts usually break off, in turn requiring drilling out the broken bolts and installing helicoils, or, at worst, requiring replacement of the cylinder heads. He also said, after all of the work is completed to replace the manifolds and the gaskets, they will likely start to leak again in as little as 10,000 miles. He said the only permanent solution is to install a Banks system, or, at the very least, go to 3.5 - 4 inch diameter exhaust beginning at the point that the exhaust from both sides combines into one pipe. (He also said this problem has NOT been resolved by Ford, and that the V-10s are prone to the same problems, because they, too, funnel the exhaust from 2-inch pipes on each side into a single 2 pipe and exhaust system, and this creates too much heat. He said the GM 454s are bad for this too. And he put the icing on the cake when he said it would not pass a government safety check (required to transfer ownership in Ontario) as it was. Result: I lost the sale! Has anyone else heard of this common problem? Are there any recommendations for solution? If this guy is correct, it sounds like ANYONE would be nuts to buy a gas-powered motor home! My '86 Coachmen had the manifold problem. Basically both manifold gaskets blew, due to what was explained to me as constant expansion-contraction, from heating/cooling cycles. What I learned was that due to a combination of things (Like a retarded cam timing and air injection for exhaust emissions), the manifold gets very hot under load (like going up a large hill), and then when you crest the other side, it cools down rapidly somewhat. This almost continual cycle causes the manifold to warp somewhat, making it easy to blow the gasket. The exhaust manifold has also been known to crack as well. Fixing it is no picnic. Since the E350 is basically a van, the big block engine is wedged in there, making accessability problematic at best. The heating/cooling also weakens the manifold bolts and they break very easily. If the wrong (read: inaccessable) bolts break, there is no alternative but to remove the head to drill out/rethread. This is what I went through with mine, and it ended up costing me almost $1900 when it was all said and done. I have since tried to minimize the problem reoccuring by disabling the air injection system, and advancing the ignition timing somewhat. It took over 56K miles to fail. Hopefully by the time another 56K appears, I'll have long since sold it. Dave

Problem is common. Tim and others,  I pull a trailer with my E-350.  Is the van prone this same problem, or just motor homes where the engine exclusively pulls the heavy weight all its life? Thanks George