Exhaust manifold heat shield! Please HELP!!!

[TrailblazerLT]

Ok guys I am pretty sure I have a leak at my exhaust manifold but I have not been able to get the bolts off the heat shield so I can check. The bolts are pretty much rusted on there and won't budge. I was going to just cut them off and go from there but I wasn't sure if I would have problems leaving the heat shield off...or after I cut them off how could I put the shield back on???

 

[ksimm92]

I'm sure its on there for a reason, so it would probably be best to some how get it re attached. one thought that came to mind was if you were to cut the bolts to get it off, you could maybe get some stainless steel hose clamps and attach it that way? I don't exactly remember if there would be a spot to fit them off the top of my head. I wouldn't worry about the heat on the clamps, I used them to hold some exhaust wrap on my honda shadow pipes and held up great.

 

[The_Roadie]

Sometimes PB Blaster and time will work on them, unless you have to drive the truck. Or impact tools. But the heat shield can't be left off. Very critical to protect things. I seem to remember the bolts are threaded studs into holes in the exhaust manifold, and if you break stuff off you will be in for a project to drill out the studs and replace them. But if you're pretty sure you have a cracked manifold ( exhaust noise that gets softer as the manifold heats up) then you won't care about breaking the shield bolts. You will be MUCH more concerned about breaking the bolts that hold the manifold to the head.

 

[TrailblazerLT]

Sometimes PB Blaster and time will work on them, unless you have to drive the truck. Or impact tools. But the heat shield can't be left off. Very critical to protect things. I seem to remember the bolts are threaded studs into holes in the exhaust manifold, and if you break stuff off you will be in for a project to drill out the studs and replace them. But if you're pretty sure you have a cracked manifold ( exhaust noise that gets softer as the manifold heats up) then you won't care about breaking the shield bolts. You will be MUCH more concerned about breaking the bolts that hold the manifold to the head.

Hmmm from what you described I am not sure if its cracked but can you elaborate a little more on the sound? I have a tick, I guess under acceleration from the passengers side but nothing while at idle... it's as quiet as can be at idle.

So I was thinking I might need a new gasket or the very least might need to tighten the bolts, or so I am hoping. The bolts on the shield are pretty caked with rust and I have tried pb blaster but the nuts started to round so I stopped.

 

[The_Roadie]

Cracked exhaust manifolds allow exhaust noises to escape, and they sound like a bad muffler. And the cracks usually get smaller when the unit heats up, so the noise is noticeably worse when cold.

There are special sockets to bite into and grab rounded nuts.

Ticking can be other things. Use the long screwdriver to the ear trick and see if you can localize it.

 

[TrailblazerLT]

Cracked exhaust manifolds allow exhaust noises to escape, and they sound like a bad muffler. And the cracks usually get smaller when the unit heats up, so the noise is noticeably worse when cold.

There are special sockets to bite into and grab rounded nuts.

Ticking can be other things. Use the long screwdriver to the ear trick and see if you can localize it.

I'll see what I can come up with...what else could the ticking be?

 

[The_Roadie]

Is it proportional to engine RPM, or something else like once per second? 1 Hz could be the fan clutch. Other items are belt idler and tensioner pulleys, cam chain, power steering pump, etc. Try to localize it better with a mechanics stethoscope. Harbor Freight has cheap ones.

 

[TrailblazerLT]

Is it proportional to engine RPM, or something else like once per second? 1 Hz could be the fan clutch. Other items are belt idler and tensioner pulleys, cam chain, power steering pump, etc. Try to localize it better with a mechanics stethoscope. Harbor Freight has cheap ones.

Ok I will check it out but I was already planning on replacing the tensioner and the idler pully, only because the tensioner seems to be frozen and won't move so I can remove the belt. I am going to do those and then see what happens. Thanks for the help and I will keep everyone posted!