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jerryu45
08-06-2009, 01:51 AM
I am attempting to put in a new intake manifold in a 1998 merc grand marquis with the 4.7L engine. The the third bolt (in the tighting sequence) attaches through a bracket which also mounts to the rear of the new intake manifold. The bolt was tight and torqued when removed from the old intake manifold, but now there is at least 1/2 inch left on the bolt when tighting it down, and keeps turning but does not get any tighter. Is there a spacer, or another item that should mount in the same place to take up the slack, or is it something else I am doing wrong?:eek:

admin
08-06-2009, 09:24 PM
Hi jerryu45,

Are all of the bolt holes in the new manifold casting the same depth? Is it a stock manifold? If that hole's casting is thinner on the new manifold, then a shorter bolt would be required. The other disconcerting thing here though, is the fact that the bolt is turning in its hole, but not getting any tighter. That would indicate a stripped hole.

The manufacturer doesn't specify if the bolts are of different lengths (usually the manufacturer, and Haynes, would indicate this).

Was there any oil or coolant in any of the holes when the bolts were installed? If so, the hydraulic pressure created when the bolt is tightened down can become so great as to actually damage the engine block, either by cracking it, or by causing the hole's threads to strip out.