btytc

OK I, had this anoying exhaust leak noise under the hood coupple days after I did vacuum job.So after a close exam. I decided that it is going to be either a gasket between downpipe or turbo and manifold so I bought new once (paid arm and a leg) and installed them.
Same thing,so I checked again all the areas possible,even removed and blocked EGR and AWS and same thing.When you lean over the engine and rev it up you can even see smoke coming from somewhere behind turbo and exh. manifold.Now I have everything apart again even exh. man. Examined for cracks or broken gaskets and nothing .All seams to be fine,Except you can see carbon deposits on bottom of intake manifold.Is it possible that I could have an exh. leak from intake man.???
Air pump is removed too.
Any suggestions greatly appreciated.

Rodeo Jones

Did you replace the studs on the manifold?
They could have gotten slightly tweaked enough that they are not sealing against the gasket.

Get the new ones from your local Mazda dealership.

That would be in Timonium for you right off York Rd. I believe.

btytc

No I did not replace studs,but I can see on the gaskets that they are a good seal.
Hey,you know it around here, Rodeo?

mjw

iTrader: (1)

Make sure your mating surfaces on the manifolds and downpipe are still flat and meet flush with the gasket, a warped manifold won't seal well against the gasket.

btytc

I'll check tommorow,but I dont think that's the problem.
There is carbon (black powder) deposit on engine block between LIM and Exh. man.Could it be engine mechanical problem?The car runs fine (idle little rough w/cold eng.)and boost patern is aprox.10-12-10,but I dont trust my Autometer gauge 100%.....
It really looks like it's coming from LIM?!?!?

93blackrx

The exhaust rerouter may not be sealing/you know where I'm talking about right? at the bottom of the intake man. is the lower intake manifold torqued down to spec. get a torque wrench and a workshop manual.

hope that helped out, Matt

btytc

Matt,
that's probably what it is.I have everything apart except LIM so it's not going to be abig deal to pull it off and check it out.The only thing is,I replaced it like 500
miles ago.But on the other hand it all started after I replaced it.
Thanks and let you know on progress

btytc

This is where I think its leaking from(red arrow)
[IMG]E:\IMAGES\E-Mail\exhaust leak.jpg[/IMG]

R Xplicit

LIM gasket would be what sounds right to me...

BlackR1

yup, sounds like a LIM gasket. Make sure you properly torque down everything. If it's not torqued down correctly, you'll get some gasses seeping out, hence the black deposits.

If it's not that, it might possibly be a crack on your turbo/wastegate manifold

btytc

Ya I know,but what I did not know there is exhaust gas in LIM.

btytc

If it's not that, it might possibly be a crack on your turbo/wastegate manifold

No,I've checked like 100 times.I'm finally getting somwhere,you can not imagine how much time I've spent looking for this problem...It just did not make sence ...

BlackR1

yeah theres no exhaust gasses in LIM, but some oil gets in the intake tracts and that is probably causing that black mark.

btytc

Guess what!There is exh.gas in LIM,I guess for EGR???

matwey

Ask around some shops and see if they have a "smoke machine". They hook it up where you tie into for the boost guage and it circulates smoke throughout the vacuum system. If there are no leaks, it will make its way out your intake filter. No harm is done at all. Takes 5 minutes.
Did it to mine and saw that I had a good one coming from the LIM. Looked like it was smoking a cigarette. If that's not it, then it is an exhaust leak. Good luck!

SPOautos

If its not you LIM, I bet your exhaust manifold is slightly warpet.....its very common actually.

You can pull it and use a ruler or something to see if the surface is perfectly flat. If not you can use a belt sander or something to flaten it out.

STEPHEN

btytc

It is LIM,leaking from the bottom.When I was replacing it last time (3 month ago) I guess did not clean the old gasket perfectly.Piece of old gasket got stuck on the bottom stud,and it developed a small leak between bottom studs.
This one was so far the hardest problem to solve .So far,anyway.
Thanks guys for your help
Karel (with finally lesser headache)

btytc

OK
got it fixed,LIM gasket.
Now I have boost problems for a change,going non-seq.