AWD-RWD racer

iTrader: (5)

ok, i have an exhaust leak, I cannot find it though, you can hear it standing around the car and in the car. kinda like a put put put put noise. If i get under the car I cannot see it or see any traces of an exhaust leak, but I can def smell it. Im thinking maybe the turbo manifold is loose somewhere??? has anyone else ever had a mystery exhaust leak, even when I took it to pettit racing they couldnt find it. yet they charged me $75 TO TIGHTEN THE TURBO MANIFOLD YET THE NOISE AND LEAK IS STILL THERE.


any ideas??? thx

dgeesaman

iTrader: (7)

I know how hard it can be - I've fought with warped flanges for some time.

This sounds labor-intensive, but you can dump a little ATF in the spark plug holes and start it up for a minute, then disassemble the exhaust. The ATF smoke should help make the leak path more visible when you look at the gaskets. I would do it on a cold engine and maybe use a plate to partially block your muffler - the extra backpressure should help push the smoke out of the leak. Then shut it off before it all gets too hot.

Another method is to use a feeler gauge when assembling the exhaust. With the bolts only snug tight, go around each joint and see if it can fit in there. Wherever it fits is very likely a leak.

Dave

iceman4357

iTrader: (2)

Does it smell under the hood or does it smell when you are walking around the car? I would say start it and get under the car, pour water on the exhaust until you see bubbles. Look where the welds are for the DP,midpipe and catback.

dgeesaman

iTrader: (7)

Be careful with the water - it boiled off instantly when I tried it. It simply won't work anywhere above the main cat.

The other complication is that the heavy heat coming off the turbo/exhaust area causes signficiant air circulation, even at idle. Using the smoking insect repellent punk didn't work well since the air in that area just wasn't very still.

Dave

IRPerformance

iTrader: (41)

I had an instance where I pulled the turbos and manifold and repalced all the gaskets and the leak would still not go away. Ended up being one of the small bolts on the turbine housing backed out. Took forever to find it.

caredden

iTrader: (148)

If you can, spray soapy water on it and look for bubbles.

I ended up using a shop vac, reversing it to blow, stuck it in the exhaust, stuck rags around the nozzle to seal it up, sprayed soapy water at suspected places and watched the bubbles build...

AWD-RWD racer

iTrader: (5)

thanks for all the good ideas, im gonna get on it as soon as i can.


I smell it in the car . and when I pop the hood i smell the exhaust in the engine bay.

NewbernD

iTrader: (1)

You can also make yourself a poor-mans mechanics stethescope. Get 3 feet of vacuum line. Stick one end in your ear. Move the other end around the suspect areas. You should be able to narrow down by sound much quicker this way.

dgeesaman

iTrader: (7)

Now that is a good idea.

(Did you know that an ordinary shop-vac can generate about 2psi of dead-head pressure?
A co-worker of mine exploded a prototype lander airbag assembly once when he was only trying to fill it with air to get it to take shape. 2 months of sewing and 40lb of Kevlar went POP in 3 seconds. Oops. Reviewing the power rating on the vac (we were in shock) it showed that the shopvac had plenty of power to do what it did)

Dave

wankelrx

Might be your lower intake manifold leaking. https://www.rx7club.com/forum/showthread.php?t=573665
If you get far under the car you can see if the LIM gasket is blown out.

StLABC

I agree..........my phantom exhaust leak turned out to be a blown LIM gasket. Stock ones were paper I think.

IRPerformance

iTrader: (41)

or use a makeshift stethascope. A hose and put it to your ear and listen to near where you think the noise is.

sevensheaven

iTrader: (1)

I agree..........my phantom exhaust leak turned out to be a blown LIM gasket. Stock ones were paper.

I have had two motors with this problem and both were paper gaskets on original motors.

I beleave I posted this picture on a simular question before. Look at all the soot between the exhaust ports!

Terry7