I have a 98 P32 with 72000 miles and do all my own maintenance. While servicing the brakes on drivers front wheel I could clearly see the manifold was cracked but does not appear to be leaking. I understand this is a common problem with these engines. I would like to avoid changing this if I don't have to do to the fact that the mounting studs commonly brake off which requires drilling and tapping and possible head removal. Since it is not leaking what are my chances that it wont get worse on our way south in January. Thanks in advance for your advice. Ken

Where is it cracked, vertical crack in between the exhaust ports? If so don't worry about it. The replacement manifolds now have gap or cut in between the exhaust ports to allow for expansion. I have a 94 and mine cracked there, I had to replace it because the rear stud was already busted and the studs for exhaust pipe flange wouldn't come out. For $50 I wasn't going to try and remove those 3 studs. Anyway the replacement had a gap right where mine was cracked.

A no cost solution. The manifolds will have to be removed. Use a drill to elongate each bolt hole approx. 1/8th inch on each side of bolt hole. This will allow the exhaust manifold to expand and contract as it heats and cools. Torque bolts to spec.

Where is it cracked, vertical crack in between the exhaust ports? If so don't worry about it. X2If it is not leaking leave it alone. IMO the risk of a broken hard to remove bolt is too high.

If you 'Someday' determine that U should have replaced the manifold, make sure you get the BEST metal, Aftermarket manifold gaskets you can find! This is the only thing that will protect manifolds. Many 454s came from factory with no gaskets! If U don't live in a state with Exhaust Inspections, Remove the Air pump that blows air into the exhaust manifolds & get shorter belt. Use Vice-Gripe pliers to pinch off each(8)cylinder air tubes.

My 89 454 manifold cracked at 4,000 miles. Very common.

Cracked 454 exhaust manifolds | Good Sam Community

jolooote
Explorer
Nov 14, 2013
If you 'Someday' determine that U should have replaced the manifold, make sure you get the BEST metal, Aftermarket manifold gaskets you can find! This is the only thing that will protect manifolds. Many 454s came from factory with no gaskets! If U don't live in a state with Exhaust Inspections, Remove the Air pump that blows air into the exhaust manifolds & get shorter belt. Use Vice-Gripe pliers to pinch off each(8)cylinder air tubes.
okgc
Explorer
Nov 14, 2013
Where is it cracked, vertical crack in between the exhaust ports? If so don't worry about it.
X2

If it is not leaking leave it alone. IMO the risk of a broken hard to remove bolt is too high.
txtode
Explorer
Nov 14, 2013
A no cost solution. The manifolds will have to be removed. Use a drill to elongate each bolt hole approx. 1/8th inch on each side of bolt hole. This will allow the exhaust manifold to expand and contract as it heats and cools. Torque bolts to spec.
Hank_MI
Explorer
Nov 14, 2013
Where is it cracked, vertical crack in between the exhaust ports? If so don't worry about it. The replacement manifolds now have gap or cut in between the exhaust ports to allow for expansion. I have a 94 and mine cracked there, I had to replace it because the rear stud was already busted and the studs for exhaust pipe flange wouldn't come out. For $50 I wasn't going to try and remove those 3 studs. Anyway the replacement had a gap right where mine was cracked.

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