As a few of you might know from my other thread (see Matt's cylinder head rebuild in the 7MGE forum) I rebuilt the head on my 7MGE back in February. Once I got the valve shims done everything was running and sounding great (actually it was too quiet, but a new, sportier exhaust will have to wait). However, about 2 weeks ago I developed what sounded like an exhaust leak. It seemed like it was coming from where the exhaust manifold connects to the downpipe. I checked, and sure enough the nuts were very loose even though I know they had been tightened down when I did the head rebuild AND new gaskets were used at this spot. So I tightened them up, but the exhaust leak sound was still there. After looking at the TSRM I noticed that the nuts were not supposed to be reused; so I ordered and fit new ones (making sure they were good and tight). The noisy exhaust remained. To make sure it was coming from this spot I blew air through the tailpipe and sprayed soapy water around this area. Sure enough bubbles formed exactly at this spot.
My question is why did it take a month or so for the nuts to come loose? More importantly why didn't tightening the nuts up (especially with the new ones) fix the leak? Is it one of those things where you only get one shot at squishing the gasket and if it comes apart even a little you have to start over with a new gasket? Or, do you think it was because I used the gaskets from the non-Toyota engine gasket kit and maybe they just didn't fit right? Or is there something else I am missing completely in terms of correctly installing the gaskets in the 1st place? That last question is very important as I have ordered new Toyota gaskets and even new studs to go with the new nuts I mentioned previously. Your thoughts are appreciated as I hope to work on it tomorrow.
My question is why did it take a month or so for the nuts to come loose? More importantly why didn't tightening the nuts up (especially with the new ones) fix the leak? Is it one of those things where you only get one shot at squishing the gasket and if it comes apart even a little you have to start over with a new gasket? Or, do you think it was because I used the gaskets from the non-Toyota engine gasket kit and maybe they just didn't fit right? Or is there something else I am missing completely in terms of correctly installing the gaskets in the 1st place? That last question is very important as I have ordered new Toyota gaskets and even new studs to go with the new nuts I mentioned previously. Your thoughts are appreciated as I hope to work on it tomorrow.
