# Exaust manifolds cracked. Oxy/acet melt fix?



## terrapro (Oct 21, 2006)

I have a set of heads in the machine shop being rebuilt. While I have them off I have a crack in my drivers side exaust manifold, can I melt the crack back together with my oxy/acet torch with success or should I just replace it?


----------



## Morrissey snow removal (Sep 30, 2006)

are they cast or steel i would weld them up unless they are totally rotted


----------



## terrapro (Oct 21, 2006)

No they are solid, just typical crack chevys get. They are stock cast not steel tubing.


----------



## TJS (Oct 22, 2003)

Nope. Cast iron. Forget it. They are cheap on ebay.


----------



## basher (Nov 13, 2004)

Forget welding them manifolds don't weld worth crap not even 99.99 nickel will bond them. The expansion and contraction will cause even brazing to crack.


----------



## Morrissey snow removal (Sep 30, 2006)

never realy thought of that good point


----------



## terrapro (Oct 21, 2006)

Well I broke off a stud on the exit side so I had to blow it out with the torch and I keep breaking and dulling drill bits trying to drill a good hole so I might as well buy new I guess.


----------



## terrapro (Oct 21, 2006)

Can these be replaced with a set of flowtech headers?


----------



## Holland (Aug 18, 2010)

Help to know what truck you're talking about


----------



## MickiRig1 (Dec 5, 2003)

Look on the Internet for them. I picked up a pair for my Ford 5.8 for $105 dollars. With free shipping! A bolt - stud kit from NAPA was $20. The cheapest manifolds I found around here were $180 a pair.


----------



## Builder630 (Dec 23, 2011)

I replaced the passenger side exhaust on my 89 gmc3500 5.7. I had like 3 snapped studs... I welded a nut onto the stud with an arc welder( my MIG wasn't working). After a little lube I backed out the studs with the welded on nuts with no problem.


----------



## Builder630 (Dec 23, 2011)

Btw I did try welding a crack on the cracked manifold I was removing, and there was way too much distortion. The bolt holes wouldn't line up around the welding.


----------



## DIRISHMAN (Jul 30, 2010)

MickiRig1;1494582 said:


> Look on the Internet for them. I picked up a pair for my Ford 5.8 for $105 dollars. With free shipping! A bolt - stud kit from NAPA was $20. The cheapest manifolds I found around here were $180 a pair.


Hey Mick are you say you got Headers or manifolds?/ I have the same motor in my 96 250hd 5.8 .Didnt think the 5.8 had this issue liker the 5.4


----------



## SnowPro93 (Oct 25, 2006)

i just put manifolds on my 02 2500hd. I had an exhaust leak from snapped studs but while there out you might as well replace them. I think mine were about $175/pair for stock replacement with upgraded gaskets and the bolt kit. Headers I believe should bolt in place of stock and most of the time are cheaper just make sure you use a good gasket and not the garbage composite ones or you'll have problems.


----------



## DIRISHMAN (Jul 30, 2010)

Yah lookin at headers and will use the best I can find lookin at a set of kOOks


----------



## MickiRig1 (Dec 5, 2003)

My Manifolds on the 5.8 for the most part just rusted out. They got cracks when the casting got too thin. I replaced them with OEM style manifolds. The bolts and stud replacement is just the way I do things. I had to drive a 12mm impact socket onto the rusted globs of nuts& bolts.. I got everyone out with a little flame wrench persuasion.
The truck has been a plow truck it's whole life. This was at least the 3rd set of manifolds. The last bolt I took off had a lug nut for a spacer.


----------



## DIRISHMAN (Jul 30, 2010)

Geeze a lug nut what no washers


----------



## DIRISHMAN (Jul 30, 2010)

What ya think about headers


----------



## MickiRig1 (Dec 5, 2003)

They must of put the wrong lenght bolt in the last bolt hole.


----------



## DIRISHMAN (Jul 30, 2010)

Nice one good thing they didn't build them for a living


----------



## snowplowpro (Feb 7, 2006)

I bought my 96 f250 going on 3 or four years now put new manifolds in when I got it. there leaking already well for a while now there not to loud yet but after this winter they will be.


----------



## oldmankent (Mar 2, 2001)

Cast can be welded by someone good. Have them do it.


----------

