[Supras] Help me locate an exhaust leak

[Hacker J]

I was never able to remove the three bolts with the downpipe on the car (turbo version). I needed
a few feet of extensions just to reach them, and then under the car I didn't heave the leverage to
bust them loose. I sawed off the bolts at the cat and removed the whole assembly. Off the car I
could apply full force with a breaker bar to get them off.  Broke a 1/2" deep socket if I remember
correctly.

I would recommend getting new manifold bolts and studs. They are not expensive and the nuts have
built in locks that will definitely be trashed on the original rusty ones you currently have. RTV,
loctite, etc is a no go with exhaust systems. I did my helicoil with the head off the car, but I
remember a writeup somewhere for the on-car job.  Only the back stud appears to be a major pain
due to tight quarters.

Jon

--- supras-request at supras.com wrote:


> Hi Khalid,
> 
> I undo this last bolt and it came out fine with no stripping.  However the 
> nut was frozen onto the stud and came out as a whole assembly when I was 
> backing it out.  Havent't had a chance to check the others studs/bolts yet 
> as I don't have much time to work on it just yet.  I did however tried to 
> snug them up about 1/4 to 1/2 turn without a torque wrench but just by feel 
> so that gve me hope that the threads are still intact
> 
> 
> Also I bought a Felpro gasket but afterward got to thinking if using an 
> aftermaket instead of OEM would it mess up in getting  the true torque spec 
> of 29feet-lb and thus cause the stripping of the threads.   I wonder if this 
> might be the cause of people that have had stripped thread since I found an 
> article that mention gasket material and construction dictates the torque 
> spec.  Here is the link for it http://www.boltscience.com/pages/gasket.htm .
> Due to shortage of time I am dreading the prospect of helicoiling and just 
> know that I would be running into a lot of time wasted in removing the 3 
> bottom bolts connecting from exhaust manifold to downpipe in order to get 
> access.  And that doesn't include drilling/tapping/helicoiling time .  Was 
> told by the Autozone guy that I can avoid removing these 3 bolts since the 
> manifold swings out 2-3" to allow me enough clearance to slip in the new 
> gasket assuming that I don't have any stripped threads.  Do you have any 
> tips or tricks in removing the 3 bolts?
> 
> In any case I also purchase OEM Toyota gasket and they are built in 5 layers 
> : perforated steel layer-composite abestos layer (guessing on the 
> abestos)-smooth steel layer-composite layer again-smooth steel.  All held 
> together by rivets.  The Felpro is built in 3 layers , a composite layer 
> sandwiched by a layer of perforated steel on each side.
> 
> I couldn't find any RTV that can handle the high heat since I am a bit 
> concern that perhaps the leakage is due to warpage in the back area either 
> from the head or the manifold mating side and was hoping that the RTV 
> sealant might address these minor imperfections and allow for a quick cheap 
> fix till I have time to do a proper job.  I am awared of warpage allowance 
> of  .10mm max on the head side and .75mm on the manifold side and the proper 
> way is to machine them down.  But  I also wonder how often does warpage 
> happens.  The flow of the leak just like a knife cutting action which lead 
> me to believe that it's warpage.
> 
> What gasket manufacture did you use and did you use any RTV?  Would love to 
> hear from others also on this question.
> 
> I know I am asking lots of questions but I truly appreciate your help and 
> everyone else on the list that have responded.  I also know now that this is 
> the cause of lean reading on my emission report.
> 
> --- On Sun, 4/20/08, supras-request at supras.com <supras-request at supras.com> wrote:
> 



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