Checking for pre turbo exhaust leaks

[4gfun]

I have a boost fade problem that no one is responding to for some reason.

One of the suggestions I have received in the past on a not completely related thread is that my boost fade may be due to a pre turbo exhaust leak. I was under the car the other day and noticed what appeared to be a "line" in the casting on the exhaust manifold. I don't know if that is part of the casting or not, but I figure that I would hear an exhaust leak if there was one. I figure the"line" would have black soot around if it is truly a leak. There is no way to get a closer look at it either because of the car's setup (GVR-4's with external wastegates can be crowded)

Anyways, could you all tell me which components are pre-turbo and which if any have a tendancy to crack etc?

Also, exactly what checks can I run on the turbo to see if the turbo itself is bad?

Finally, I can see that one of the outer exhaust manifold studs is broken and another is not fully tightened...looks like it is a pain to tighten.

Any precautions to take when removing the exhaust manifold? What about replacing the broken stud while I am there?

I seriously have bad luck with bolts on exhaust systems and don't want to mess anything up worse.

Thanks!

 

[agentorange313]

If you have a pre turbo leak, check to see if there is black smoke around the manifold where the gasket is located. That's an indication of an exhaust leak, and an improper sealing gasket. If there is no sign then check you turbo gasket. 7cm or the 6cm one depending on what you are running.

IF your manifold has cracks you will see white residue and staining along the cracks.

how old is your car? if you manifold rusted on?

The absolute last thing you want is to break an exhaust stud and have to deal with removing it and getting a new one. PB blaster is you best friend currently. Drench the manifold and all the nuts. Make sure its saturated. Let it sit for an hour then reapply.

You are going to have trouble reaching the right bottom most nut. The powersteering bracket tends to be in the way.

 

[4gfun]

Thanks for saving me some time!

 

[agentorange313]

np at all

change the forum to resolved

 

[pboglio]

Run Seafoam thru the motor. Any exhaust leaks will show up big time. Simple.

 

[92EagleAWD]

Run Seafoam thru the motor. Any exhaust leaks will show up big time. Simple.

x2 if you have one and use seafoam, that badboy will show up crystal clear!

 

[pboglio]

I have a boost fade problem that no one is responding to for some reason.

One of the suggestions I have received in the past on a not completely related thread is that my boost fade may be due to a pre turbo exhaust leak. I was under the car the other day and noticed what appeared to be a "line" in the casting on the exhaust manifold. I don't know if that is part of the casting or not, but I figure that I would hear an exhaust leak if there was one. I figure the"line" would have black soot around if it is truly a leak. There is no way to get a closer look at it either because of the car's setup (GVR-4's with external wastegates can be crowded)

Anyways, could you all tell me which components are pre-turbo and which if any have a tendancy to crack etc?

Also, exactly what checks can I run on the turbo to see if the turbo itself is bad?

Finally, I can see that one of the outer exhaust manifold studs is broken and another is not fully tightened...looks like it is a pain to tighten.

Any precautions to take when removing the exhaust manifold? What about replacing the broken stud while I am there?

I seriously have bad luck with bolts on exhaust systems and don't want to mess anything up worse.

Thanks!

Remove exhaust manifold, pull broken stud from head by any means neccessary. Grab with vice grips, bolt extractor style drill bit, you name it.

Then surface grind exhaust manifold surfaces to about +/-.005" flatness across length of manifold/head flange if manifold is still serviceable with no cracks. Port work here will do wonders if not already done. Then go out and get one of those copper exhaust manifold gaskets with the crush seals, or a 2-3 layer EVOIII style exhaust manifold/head gasket. Same procedure for turbo/manifold flange, check for flatness, surface grind if necessary, then use OEM style 7cm sandwhich gasket and/or port if no big internal cracks present. Could be a bad turbo, but in almost 20 years I have yet to lose a mitsubishi OEM turbo. You can check for axial and radial shaft play by removing intake pipe, only small amount of play should be noted. If your motor puffs smoke its possibly the turbo oil seals.

 

[4gfun]

Thanks all....I will try to run the seafoam through the motor and see what happens.

I really hear no exhaust leaks though....but it is worth a shot! Then I will take care of the exhaust manifold. Good news on the turbo!