Engine/Transmission (1998.5 - 2002) Loose/missing exhaust manifold bolts

[ramjet]

Noticed an increased engine noise [beyond the normal diesel clatter] and a "perceived" lack of turbo spool up. While checking, found exhaust leaks at the mainfold. The lower bolt and spacer on #6 was missing, the upper bolt was backed out about 1" and ready to fall out, and the upper and lower bolts on #5 were backed out about 4 to 5 turns. Considerable blow out of exhaust on 5 and 6, especially when reving up. Don't understand why they came loose, most people have trouble removing them. This is all original installation material, not been worked on prior to this. Top bolt on #6 kept the gasket from falling out. All the bolts on #1 thru #4 were tight. Replaced the missing bolt/spacer and retorqued the loose bolts and all is back to normal now, I guess. The exhaust leaks are gone, the noise is down, and I "feel" like the turbo spools up quicker.



Any similar problem with the mounting bolts coming loose? I used loc-tite blue on the bolts but don't know if it holds up at these temperatures.

 

[RustyJC]

See TSB 09-002-01.



Rusty

 

[Sean Flanagan]

This is a very common problem. It is due to the thermal expansion and contraction of the manifold. My old 98. 5 had one of the bolts missing for about 100k miles. I think the TSB mentioned above has a safety wire for the bolt so it doesn't back off too much.



If you are running extra power, sometimes the bolts actually break off due to the expansion. Sometimes the manifolds evan crack.

 

[RustyJC]

I think the TSB mentioned above has a safety wire for the bolt so it doesn't back off too much.

Try clicking the link I provided. The TSB supplies bolt retention plates.



Rusty