Jameson_IXMR

iTrader: (5)

So my car has been garaged for a while, started a little, driven mabye 15 miles and that was yesterday. I havent washed it, so yes I know it is dirty. But I noticed this evening while investigating a boost leak that there was suit like exhaust gas all over my valve cover, just in one spot. Like it shot up from the manifold or o2 housing area. But the suit is only on the valve cover, and the exhaust checks good. Its also blowing out my hood vent apparently.
Your thoughts?? Recently I changed my downpipe to the QTP, I dont see how it would blow back straight up if that were it though. Any ideas, its late.

I already wiped it off the valve cover, but you can see where it was, only on the front and top, and only right over the manifold...




Could be my imagination, and its just dirty though.....
thanks

Clutchdc5

iTrader: (1)

for an IX, thats a fast exhaust leak, have u ever removed your manifold?

Jameson_IXMR

iTrader: (5)

The manifold has never been removed, there is less than 2500 miles on the car.... Think its the manifold??

Jameson_IXMR

iTrader: (5)

I cant see it being the manifold, everything on the top-side of it looks clean, seems like it came from the front of the car (impossible) or straight up from under the manifold but its all clean down there. I dont see how it could blow straight up from a downpipe seated incorrectly. I think I will clean it and see if it happens again, might just be dirt buildup, my cutout was leaking until yesterday, mabye some gasses found their way up front?(doubt) any more suggestions guys?

evo150

iTrader: (51)

its your downpipe leaking at the donut gasket.....give me a minute ill find some links

evo150

iTrader: (51)

check out this link, and read his fix for it in post #21 https://www.evolutionm.net/forums/sh...e+exhaust+leak is his picture of the soot on the valve cover similar to yours before you cleaned it off?
the reason the soot is on the front of the valve cover is while you are driving, the air is moving over the hood vent and pulling heat out of the engine bay (cool air enters through the front bumper). if the downpipe is leaking, the soot will be pulled up the engine bay (some collecting on the valve cover) and out of the hood vent.

Jameson_IXMR

iTrader: (5)

Yup, thats what it looked like..... Reading that thread now.
Your a lifesaver bud!

Jameson_IXMR

iTrader: (5)

They suggest changing the Donut gasket. Well my gasket is special from QTP, I think I will try re-installing the downpipe unfortunately. Then wipe away any soot and if it comes back I guess Ill get on the phone with QTP.

evo150

iTrader: (51)

while you are re-installing the downpipe, check for more signs of soot coming from between the downpipe/o2 housing (just to verify this is the problem). what type of gasket/bolts does the QTP downpipe use?

Jameson_IXMR

iTrader: (5)

Its the standard type donut gasket, just very large in size to accomodate the 3" DP. Do you think putting a very light bead of red-rtv on the gasket would help some? I might try that.

Oh the bolts, are sort of this T shaped machined piece with a threaded bolt that slides through the middle to the O2 housing. Not really positive why this method is used, but it seems pretty common. Mabye Im an idiot and have them installed wrong lol.

evo150

iTrader: (51)

wouldnt hurt. just make sure that you tighten the downpipe bolts evenly, 2 turns for left bolt, 2 turns to right bolt and so on, then torque it down to the specific specs.

Jameson_IXMR

iTrader: (5)

Any idea the torque value off hand? I was provided with a generic instruction manual that had nothing pertaining to an evo in it.

Still not sure how the gasses come back up exactly, unless you mean that the gasses leave soot down there and the air brings it up.
??????

evo150

iTrader: (51)

as you are driving air is flowing over the hood vent "pulling" hot air out of the engine bay. at the same time, if you have a exhaust leak(downpipe to o2 housing, manifold,etc) the exhaust gasses are being pulled up as well. ill see if i can find the link that explains this better than i can.

downpipe bolts should be torqued to 37 ft lbs

edit: link that talks about the hood vent https://www.evolutionm.net/forums/sh...nt+pulling+air

Jameson_IXMR

iTrader: (5)

Oh nono, I get it, its the ventrilli principal. Like how siphoning gas with a hose works. I appreciate all of the help, mind if I ask where you found that torque value? Are those for the factory spring bolts? I have the tech manual, but the torque value would be different between the two bolt types for certain. I guess Ill figure it out in the morning...
Thanks

evo150

iTrader: (51)

the torque value i gave you is for the stock spring bolts (from evo service manual). i would contact qtp and see what they suggest to torque them to.

be sure to keep us updated. hopefully its a simple fix