THIS for all the nonbelievers -- Newbies Read (leak test)

[Jeff_Jeske]

For the longest time I have been hearing people tell others to perform a leak test. I figured since I didn't do much work to the car I shouldn't have any leaks.

Well for shits and giggles I decided to finally test things out. HOLY SHIT did I have alot of leaks. I found both seals/gaskets at the TB were leaking, the sensor on top of the manifold was leaking, my fully tightened 1G blow off valve with new gasket was leaking, and even the BISS screw on the TB was leaking.

After fixing all the leaks the car runs much smoother especially between shifts.

So for all the non-believers that think thier car is fine since they didnt touch it.....definately get off your ass and do the test.

 

[Liquidus]

How did you do the leak tests ?

 

[Jeff_Jeske]

http://www.vfaq.com/mods/ICtester.html

 

[snoozin]

Ill second that. I thought i had a problem with my biss/isc. i went to my dad's shop today and cleaned the ic and decided to do a leak test first before i tore the wiring apart to try to stabalize the idle. no leaks on gaskets but there was a small cut on my vaccum hose that runs from my bcs to the wastegate hose. It didnt leak untill about 15 psi but as soon as you moved it you could feel the air. Fixed my idle problem and the running rich problem i had. lemme tell ya, glad i didnt get to tearing apart the wiring before i pressure checked it.

 

[Endz0r]

even if you don't think you have any leaks (can't hear it or no symptoms), you still probably got some. i think dsmjim said he didn't think he had any leaks, but he did the test and a few leaks showed up. he fixed them and now his car ran smoother.

now if i can only find the parts to make my own...stupid hick town NM.

 

[Parsalian05]

i did the test a few days ago, didnt hear a single leak... although i have all hardpipes/greddy bov. anyone know where the air goes after you put it into the system? i figured when i took off the tester, pressurized air would come out, but it didnt. could i possibly have a leak and just not hear it?

 

[snoozin]

make sure your boost gauge is moving up and make sure your actually getting pressure to hold in the intake track. i had to tape my bov return up as it was leaking out that enough to not build enough pressure to find any leaks. i dont know if it is supposed to do this but i assume as it is a pressure release valve it is. also if your getting pressure make sure you roll your vaccume lines around and slightly bend them. Like the leak i found it didnt really leak at 15-20 psi untill i moved the hose around and there was a little slit on the hose that leaked when i bent it a certain way. replacing this completly solved all the idle and running rich problem i had.

 

[psychlow]

I swear, leak testing fixes about 60% of the problems that DSMers complain about on this board.

 

[Jeff_Jeske]

In the DSMLink forums the fellas are saying to test after the turbo. That way you wont hear your oil bubble or possible exhaust side flow exiting. I fixed the majority of my leaks with copper RTV.

If you are leak free your tester should hold the pressure for at least a minute. If not you still have a leak somewhere. I used a windex bottle....I filled it with a few squirts of dawn dish soap and put about a glass of water in the bottle. Shake that up then spray the area of suspected leaks if the mixture lands on the leak....it will bubble like crazy!

My car shifts and idles soo much smoother.....its crazy way $4 in parts can do for you.

 

[psychlow]

In the DSMLink forums the fellas are saying to test after the turbo. That way you wont hear your oil bubble or possible exhaust side flow exiting. I fixed the majority of my leaks with copper RTV.

IMHO, you should really do both, just to make sure that you don't have any gasket/sealing issues between the turbo and the LICP.

If you have any issues with air leaking from the hot side to the cold side, I think you'll have bigger issues than boost leaks.

Has anyone other than GT30 CHRA owners had any problems with oil bubbling during leak testing?

 

[tighty]

I have the stock T-25 and I can hear my shiz bubbling when I did a leak test. I was wondering if it was supposed to do that...heh. Leak testing is good though, car ran 10 times better after I fixed the ones I could (some crap by the TB was leaking but couldn't find it, could hear it though!). Should be a general maintence thing =).

 

[dsm-onster]

I HAVE to believe that the leak tester works but i don't get something... what if you turn off your engine and any one of the 8 intake valves are lifted. any air you introduce to the system will just leak through there, right? fill up the cylinder and slit past the gaps in the rings, right? does it take a "minute" for it to leak down because of that? I want to try this...

 

[Parsalian05]

well during a leak test the car is off and therefore the throttle plate is fully closed right?

 

[psychlow]

well during a leak test the car is off and therefore the throttle plate is fully closed right?

Correct. Air will leak past it, but slowly. I don't know about a minute, though.

 

[Thomas91169]

i also have to vouch for the leak test. always figured that if i always tightened all the ic piping and such id never have to worry.

one day i started to get fuel cut. so i turned boost down and still got it. got a leak tester from a freind and foung a gaping hole under my tb elbow to upper ic pipe coupler. the map was reading way too much air coming in as the turbo strained to make 20lbs to the engine i guess. fixed my problem.

btw dont get too carried away with the barely audible or really slow leaks. my friend did this and had a really small leak from his valve cover and tried to tighten it and cracked his vc now needs a new one.

 

[Endz0r]

i got a few questions since i'm a newb on this...

ok, the link for the IC tester. if i use that exactly to the T, will i be able to use it on a big 16g? if not, what do i need to change (and help me out with exact measurements).

do i put leak tester in the same hole where the intake pipe goes to?

and whats this stuff about testing after the turbo?

thanks for the help (jesh im a newb!)

 

[psychlow]

Same for a Big 16G. The compressor housing is the same as a 14B.

Thomas, your friend needed a new PCV valve, not a broken valve cover.

 

[Jeff_Jeske]

For the guy who had the leak by the TB but couldn't find it....that is what the windex bottle with dishsoap is for. If you spray the area the leak will create lots of bubbles.

Oil bubbling is normal.

I went through the trouble to ensure my valves were not open. But you really dont have to. Odds are the intake and exhaust valves wont be open at the same time so you may or may not fill the combustion chamber.....either way no big deal.

If you have your PCV vented you may want to cap that off. I did.

 

[AdoreGSX]

I have a stock boost gauge...is there any procautions i need to take?
Where is the best place to hook it up?

 

[snoozin]

i had the stock boost gauge when i did this, i just used a tire gauge to gauge pressure on it. worked fine for me. i hooked it up to my turbo and capped off the bov and the valve cover vent.

 

[ninety7gst]

i did the test a few days ago, didnt hear a single leak... although i have all hardpipes/greddy bov. anyone know where the air goes after you put it into the system? i figured when i took off the tester, pressurized air would come out, but it didnt. could i possibly have a leak and just not hear it?

if you're not getting any air to hold then you probably have a HUGE air leak somewhere. u might have blown off an ic hose completly, have someone else feed the air into the intake and then feel your hand along the lower IC pipe and and the upper IC pipes, gl

 

[TurboDSM86]

leak tests are the shit. i had a problem with making 10 PSI w/my b16g and i built a tester. i couldnt hold more than 3 psi in my system. yes 3 psi. after fixing 314523454 leaks it made the biggest difference in the world. to leak testers

 

[CyberEye]

I've got a leak tester I just made a few days ago sitting right beside me. JUst waiting for a day that it's not bloody freezing or snowing like a bi*** out to do it.

 

[questhe]

Anyone else thinking about making a leak test plate that goes betweenthe TB and manifold?
I think this would help find leaks a lot better where they usually occur.

I had a leak at my intake mani to head long time ago, but that has def. been taken care of with the 2 rebuilds. You could also do another seperate test - just take out the plate.

I am thinking a aluminum 1/8" plate with a gasket should do it. To make it easy to install, I'll rebuild the manifold with bolts insteal of studs through the TB.

 

[totalburnout]

Okay so the creation of this little device seems to be like cake, is there anything a newbie needs to know while he does this test?

Assume he has no knowledge or very little knowledge regarding a turbo system.

What is this talk about testing before the turbo and after? It seems as if I should be doing both, but I'm not quite sure how to go about it.

Anything I need to plug up or cap off?

Descriptions and diagrams are welcomed. Thanks