Hi All,

I have a mineral oil smoke tester and I was wondering If I could use that to test for exhaust leaks. I assume I can just plug it into the tail pipe and send away. I am a little worried about getting the vaporized oil in the cats or on the o2 sensors. Does anything think this could cause a problem? I do have some new O2 sensors that I have been meaning to install anyway.

Would testing the exhaust in this way find out if I have leaks up near the valve covers? I hear a ticking from up there.

 

I have done it. It should be fine.

 

I'm no expert, but I'd think any oil would be burned off quickly.

I don't know how your tester is configured, but can you just run it without the mineral oil?

Or better yet, just connect a shop vac hose to the output side of the vac and stick the other end of the hose in the tail pipe. Or heck, even a hair dryer blowing into the tail pipe would probably work. A helper could hold their hand around the hair dryer nozzle to semi-seal the connection to the tail pipe.

 

Or a leaf blower!

 

Yeah I have a battery powered leaf blower I can use.

How do I know where the leaks are? Just by listening? Thanks guys!

 

only problem is you won’t be able to hear any leaks. You would have to feel any air. Smoke test is much better

 

You don't need to hear them. You don't need to feel them. Just spray a highly-diluted soapy solution like any household cleaner on the exhaust gasket joints and look for bubbles. Worked very well for me.

 

I am more concerned with leaks around the manifolds and SAI pipes. It doesn't seem like I would be able to spray soapy water way up in there.

 

Why are those difficult? Just open the hood and spray away. Those are among the easiest places to spray. Unlike somewhere downstream from the exhaust manifold, depending on how your system is configured.

 

If you have a shop vac that isn't banshee screaming, window-shattering loud, you'll hear your exhaust leaks. Shop vac will be duct taped way back behind your Disco to your tail pipe.

You will be in front of your Disco with the hood up.

Takes a single minute for the whole test. I found my exhaust leak pronto!

Best done with motor off and cold, just sayin'...