4.2 header exhaust leak (what size bolt do I need?)


cameron.rw

Member
Joined
Jul 20, 2020
Messages
31
Location
Bridgeport, OH
Since I’ve owned this 4.2 it’s had an exhaust leak and I believe I found it. A bolt is missing from the exhaust. Pictured here is the header and the missing nut. Its located Where the exhaust attaches to the header. I can see some sort of bolt still in there but it is not attached completely to the exhaust. No idea what size bolt and nut is needed for replacement. so any help would be appreciated. Thanks!!

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JeepJeep1

New Member
Joined
Dec 2, 2020
Messages
4
Location
Cleveland
Usually exhaust flange bolts 'll be either 5/16 - 18 or 3/8 -16. Then measure the length of the others. Better get 2 or more to CYA 👍
 

Brian

New Member
Joined
Nov 6, 2021
Messages
19
Location
Hernando FL
Usually exhaust flange bolts 'll be either 5/16 - 18 or 3/8 -16. Then measure the length of the others. Better get 2 or more to CYA 👍
Both of mine were broken off, but I had the advantage of needing to pull the manifold off the engine anyway. I Drilled out the first one to 3/8th, but at that point I was able to see the the original studs were a serrated pressed in stud. I heated and drove out old piece which left almost a 1/2" hole. I was lazy and just used a couple of grade 8 3/8" bolts and nuts rather than track down replacement studs.