Exhaust header leak tester

[JDEstill]

I had an exhaust leak that I could hear when the car was cruising, but could not hear or find when the car was at idle. I have had good luck pressuring up the intake system with my air compressor to find leaks on the intake side, so I decided to do the same on the exhaust side. I made a plate to bolt up to the turbine housing that I could hook my air compressor to. See attached pic. Very very *very* shadetree, but it worked! With the car off, the headers cold, and the headers pressured up I was able to find the leak easily.

After I fixed the leak and reassembled everything I tested it again and found a small leak where the header met the crossover pipe. I never would have noticed this on a running car. I was able to readjust the crossover pipe until that small leak went away. Leak-free, the car runs great.

Two points - I had thought I was going to have to loosen up the rocker arm shafts so I didn't pressure up the whole engine too, but it all worked ok without it. Maybe I just got lucky, I dunno, but it worked for me. Second point - the plywood plate deformed a little too much, after a while it started leaking there. If I was to do it again, I would use a harder material. Maybe a nice cherry veneer

Soooo.... throwing the idea out there. If anyone wants to fab up some plates to sell, you have my blessing. I just want a freebie as my royalty payment

Hope this helps somebody track down their leaks!

John

 

[WSLN 6]

You could even take it a step further and cap the end of the exhaust and do the same thing with the downpipe on. Good stuff!

 

[WINDMILL]

Sweet idea,,,,,now change them rusty v/cover bolts!!!!!!!!!!!!!!

 

[Heg87t]

Sweet idea,,,,,now change them rusty v/cover bolts!!!!!!!!!!!!!!

Wow! Tough crowd! :smile:

GREAT idea. I am going to try this also. I was going to take my headers and crossover off to visually inspect and see where I might be leaking but will give this a try. Another advantage I see is at the crossover joints. You can adjust the crossover while pressurized until you get it to seal up instead of taking off and on.

Did you use a compression tester hose to connect?

 

[charlief1]

I'll see if we can get this moved to the how to section. Very simple idea and it works. Great job and info btw.

 

[JDEstill]

Did you use a compression tester hose to connect?

Tough crowd indeed! Yes, I used the hose from a compression tester to connect my air compressor to the plate. For the hole in the plate I drilled a hole then used an old spark plug to tap it (I don't have a tap that size). Did I mention this was a shadetree effort? Air compressor was set at 5 -10 psi, that was plenty for me to hear the leaks.

I also cut out a gasket from some thin cardboard, like from a shoebox, to help seal the plate to the turbine housing. Not sure if it really helped or not. It sealed ok at first, but it leaked some there as the day wore on. That may have been because it was seeing a higher pressure after I fixed the main leak though. I still think a harder material would have worked better than the plywood. But then I probably would have needed a real tap to thread that hole, so it might not have actually made my life any easier.

For the ultimate in leak detection, you could loosen the rocker arm shafts to make sure all the exhaust valves are closed. Then you could really pressure up the headers, probably to 20+ psi.

John

 

[JDEstill]

You could even take it a step further and cap the end of the exhaust and do the same thing with the downpipe on. Good stuff!

Actually, on my car that would have been a waste of time. Notice the two piece downpipe - it will not hold any pressure whatsoever. I've got that particular downpipe on at the moment because it has my cat converter mounted to it, and I need to get the car inspected, and I have to do the sniffer test as part of that. Once inspected this two piece POS goes away, my THDP goes back on, and life gets much better!

On someone elses car that might be a good idea though, could be easier to do than the plate. Assuming no leaky spots at the joints in the system.

John

 

[Heg87t]

Hmmm...

You could even take it a step further and cap the end of the exhaust and do the same thing with the downpipe on.

Rubber plumbing cap on the outlet end of the downpipe with a hose clamp and a hole in for the air hose would be really easy to do.

Did the turbo spin while you were testing?

 

[JDEstill]

Rubber plumbing cap on the outlet end of the downpipe with a hose clamp and a hole in for the air hose would be really easy to do.

Did the turbo spin while you were testing?

If the turbo spun during my test, I wasn't aware of it. I didn't hear anything. Since there should not be much flow, just pressure, I wouldn't really expect it to spin. Unless there was a really major leak, like the crossover came off But my dinky little compressor couldn't keep up with that anyway.

I like the idea of the rubber plumbing cap. Here's another idea - block off the system somehow, plate on the turbine outlet like I did (but no hole), or plug the downpipe outlet somehow, then hook compressor up to the O2 sensor fitting. Not sure what the thread is for that fitting. Is it the same as the big spark plug thread? My compression tester hose has both big and small spark plug threads on it, but I have no idea if it will screw into the O2 sensor hole.

John

 

[Just a Six??]

If the turbo spun during my test, I wasn't aware of it. I didn't hear anything. Since there should not be much flow, just pressure, I wouldn't really expect it to spin. Unless there was a really major leak, like the crossover came off But my dinky little compressor couldn't keep up with that anyway.

I like the idea of the rubber plumbing cap. Here's another idea - block off the system somehow, plate on the turbine outlet like I did (but no hole), or plug the downpipe outlet somehow, then hook compressor up to the O2 sensor fitting. Not sure what the thread is for that fitting. Is it the same as the big spark plug thread? My compression tester hose has both big and small spark plug threads on it, but I have no idea if it will screw into the O2 sensor hole.

John

LC-1 plug is same as a spark plug so throw it on there with the end of DP capped.
Should be much easier & do it on the engine stand or in car.

 

[sams86gn]

I will be trying this very soon..

 

[TurboBuRick]

A 4ft piece of 3/8 hose works great for finding exhaust leaks. Put 1 end in your ear and scan the flanges with other.

Rick

 

[BARRACUDA1968]

Nice job!

BTW what are you using between your valve cover breather and the valve cover?

 

[sams86gn]

Just an update, I tried this and it worked great. Found leak which was on the back cylinder on the drivers side at the exhaust gasket. Just ordered some fel-pro 1400 exhaust gaskets so hopefully that won't happen again. Now I've just got to get this bolt out of the turbo exhaust housing that broke off when I was taking it off!


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[liquidh8]

I too will be doing this, the front end is off and I can easily get to all the exhaust junctions to check for leaks.