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exhaust manifold heat shield necessary?

E

EXJAY

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Had a ticking start up on my 88 K5 on the passenger side of the motor which went up with speed as the motor revs up. Thought it was possibly a loose rocker so I removd the cover and ran the motor checking the valve train. The sound didnt get any louder as I would have expected and the arms etc seem secured properly. Im thinking now I might have a crack on the manifold but whats visible outside the heat shield loks OK. How hard is it to remove the passenger shield and reinstall w/o pulling the manifold to inspect? Do I really need to have it back in place? The reason I ask it looks as if its rivited all together and may get distroyed in the process. My father-in-law told me when the Blazer was his he had to replace the same side manifold due to a crack between cyl 6 & 8 about 10-12yrs ago and had the same ticking sound.

EDIT: Wanted to add this is a orig CA truck so the smog crap is all there.
 
Heat shield is attached with the exhaust manifold bolts and studs. Cant recall exactly how many of the bolts are used in holding it on. No you don't need to put it back on, just make sure your plug wires and boots are free from touching the manifold.
 
99% of the time (it seems) the crack is under the heat shield, and caused BY the heat shield's rivets. I'm not sure how you are going to get the shield off without leaving rivet holes.
 
livid4dirt said:
Took mine off and it did not leave rivet holes.
Click to expand...

good, rip the stocker off and pray the noise was only the heat shield :waytogo:

IIRC, mine was riveted to the manifold and maybe through the manifold bolts. I remember the rivets mainly.
 
I see the 88 is different then mine was. You could always grind the rivet heads off and hack at the tin til it's off.
 
On my '89, the heat shields are attached to the block with little brackets that float them over the exhaust near the plugs. If they were previously riveted... GM must have found a problem with that & "fixed" the issue.

Mine jingle from time to time, as they vibrate against the manifold :( I keep thinking about removing them, but figure they must be there for a reason.

Clay
 
It would be easier to just remove the whole manifold than to get in there with a grinding device with all the wires and hoses and such. Besides you know it's gona be cracked, so why avoid the inevitable. Answer to actual question, No unless required for smog inspection
 
sponsoredbydad said:
It would be easier to just remove the whole manifold than to get in there with a grinding device with all the wires and hoses and such. Besides you know it's gona be cracked, so why avoid the inevitable. Answer to actual question, No unless required for smog inspection
Click to expand...
FTW, just remove and replace.
 
10-4, thanks guys. It appears it just kinda floats and rivited on both halves together around the manifold. I will just use a dremel with a cut off disk to remove it.
 
It's probably a "heat stove" if its on the passenger side,for the air cleaner to get hot air from thats what is being called a "heat sheild"..the manifolds often crack under the tin "stove",I bet you find a crack under the tin sheild once it is removed..the manifolds can crack at the point where it meets the exhaust ports also...

I've seen many small block manifolds "shrink" after being heated and cooled so many times,more than one I have taken off fell into two peices,it had cracked thru all the way around between the center and end bolts,a fine hairline crack you'd have a hard time seeing too..they sell a tool to "spread" exhaust manifolds to help get the bolts installed easier,but I have broken a few I tried using one on..hogging the holes out works better IMO..
 
Yep. How necessary is the pre-heat to the air cleaner? If this is what I find (cracked) I might just go the header route instead.
 
Meh, extreme cold it may help a little. But i live in an area that gets pretty cold in the winter and iv'e never had an issue with mine off. I have headers on my Jimmy and stock manifolds on my Blazer, i could not notice any difference.
 
Not very, if at all?

Based on your location, icing I'm guessing isn't much of a concern? I know in some locations icing does happen, but outside of the "warmup" period (which is less critical with TBI anyway) in regards to icing, that would seem to be a device installed "just in case" as opposed to "most will need it".
 
dyeager535 said:
Not very, if at all?

Based on your location, icing I'm guessing isn't much of a concern? I know in some locations icing does happen, but outside of the "warmup" period (which is less critical with TBI anyway) in regards to icing, that would seem to be a device installed "just in case" as opposed to "most will need it".
Click to expand...


Agreed. I run headers and an aftermarket cleaner, still warm up pretty quick and no problems. It doesn't get much colder than high twenties here though.
 
Humm... got the shield removed but found no crack on either side of the manifold. That bottom rivit just above the motor mount was a bitch! Only thing I can guess now (which I should have checked first to begin with :doah: ) when I get things back together is a bad seal/gasket from the manifold to the block when running. Its funny that one day no ticking then the next it started ticking right after firing it up. dunno.
 
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