Best way to diagnose and locate a potential exhaust leak?

[FlaBoy]

Based on what some people have told me, I think an exhaust leak may be responsible for the problems my car is having (stumbling/missing at light to part throttle that smooths out and dissapears at half throttle or more and when in boost). What is the best way to determine if it is in fact an exhaust leak causing this, and if it is, what is the best way to locate where the leak is? I have a Scanmaster if that would help in determining if its an exhaust leak, I jsut dont really know how to interperet the data its giving me (only had it about a month, and only had a GN for bout a year now, so its still kidna new to me). If anyone could tell me what categories in teh scanmaster i should be looking at, and what normal values should be, and what values would indicate an exhaust leak, i'd very much appreciate it. If it turns out i DO have an exhasut leak, how could I determine where its leaking? I assume only leaks before the turbo or 02 sensor would cause problems, as leaks after that would just be like having a less restrictive exhaust, but how do i narrow it down to headers, crossover, uppipe, etc? If anyone can shed light on the subject I'd really appreciate the help here. Thanks!!!

 

[Marc87GN]

I recently found a few leaks buy filling a cup with ATF I had in the garage and sucking it into the engine through a vacuum line. It made so much smoke I could barely see my car. The white smoke came out of the few exhaust leaks that I had. I have one at the driverside crossover connection I'm working on and at the band clamp on the center of the 2 piece Poston crossover.

 

[FlaBoy]

Would that hurt the engine any, to suck in atf like that???

 

[onefastcar]

no not really just lubin her up believe me it don't take much or neighbors will get mad.

 

[Lee_Burough]

GM top engine cleaner would do the same thing, only it comes in a convenient spray can. Most parts stores are going to sell a top engine cleaner in a spray can. The top engine cleaner would potentially do some good for your engine too

 

[FlaBoy]

anyone got any wisdom to share on the scanmaster? what should i be looking at, and what sort of values should i be seeing, and what sort of values would i see if its an exhaust leak?

 

[Tampa T-Type]

Sea foam works great

Get it at Discount A.P.

 

[Marc87GN]

anyone got any wisdom to share on the scanmaster? what should i be looking at, and what sort of values should i be seeing, and what sort of values would i see if its an exhaust leak?

I see high BLMs at idle and it drops from mid/high 140s to 130 when I tested with ATF. Also it drops when driving. I don't have a scanmaster so I'm not sure if it has the ability to see BLMs. I usually drive around with my laptop and Turbolink recording and making noise if my KR goes over 1 degree.

 

[turbobose13]

I do it the easy way, just pull the car in the garage and listen on both side's, because it will bounce off the wall's, and then you for carbon mark's.

 

[SITHV6]

Kinda fun...

What I like to do is buy a cheapie medical stethoscope (NOT the mechanics one) then go to the auto parts store, buy a decent aluminum brake line...pull out the audio disk thingy and tailor the brake line to fit in its place...and now u have a heat proof means of finding exhaust leaks! Kinda fun to do with friends watching...makes u look like a Dr. Fixit! ESP Good for finding header/turbo leaks! Found the common driverside header leak n a frieds GN this way. HTH

 

[Raymond Bunch]

I do it the easy way, just pull the car in the garage and listen on both side's, because it will bounce off the wall's, and then you for carbon mark's.

I agree this does work. During my rebuild I painted my headers with 1500 degree hi temp paint (Silver) color for just this reason. If you have an exhaust leak, it will leave carbon marks and you can clearly see it. Work out good, just fixed an exhaust leak Wed evening