Check for exhaust leaks by pressurizing?

[kiwigtx]

Drive that patato in there hard and far. The leak will be found in short order. But expect a good boom to go with it. Now we have a leak.

That happened at my high school many years ago .....science teacher's car......the potato came out at high speed and smashed a window while we were eating our lunch..

 

[Kimodc]

Guess one could wrap their lips around the carb creating a seal. Appears to be a stupid way to check for leaks when there is a much bigger air pump already at the intake part of things.

Wouldn’t you need an intake valve open for this to be an issue? Not sure how you would have an intake and exhaust valve both open on same cylinder at same time?

Maybe this isn’t the best way to check for leaks, but like I said, I thought the concept was intriguing. It’s pretty tight and hot and noisy under there checking for exhaust leaks with the car running, especially with my tailpipes turned down and ending at the rear axle

 

[mopar 3 B]

That happened at my high school many years ago .....science teacher's car......the potato came out at high speed and smashed a window while we were eating our lunch..

It didn't fit very well then. To do it right start with a big potato.

 

[Daves69]

Perhaps you have been throwing a banana down an exhaust pipe too long.

Oops, seems humor may have hit a sore spot.

 

[Splangj]

I had an exhaust leak years ago, heard that obvious sound. I opened the hood and it was an obnoxious leak from a cracked header tub, number 7. I’ve since gas welded it after I removed the header. Pain in the ***, but those 1-7/8 headers live! I bought those of a late friend with a ‘71 383 RR.

 

[gtx6970]

I saw on YouTube yesterday someone was checking for exhaust leaks by adding pressure to his exhaust system by switching his vacuum hose on his shopvac to the exhaust outlet and then shoving the hose in the tailpipe. He then simply sprayed down all his exhaust joints with soapy water and looked for leaks, similar to checking for leaks in a tire. For a dual tailpipe situation, you stopper the other tailpipe. This looked like a ridiculously easy way to check for leaks without working around a hot exhaust system. Are there any dangers to your engine in doing this? I can see where a valve or two may be open into the heads at any given rotation of the engine, but it is not like there is much air flow that will be carrying particles, more just air condensing and building to pressure. I don’t want to risk damaging my engine, but it sure looks like an easy way to check for leaks…….am I missing something?….. What are your thoughts?

Ive done it numerous times. Works great if your chasing an O2 sensor issue on late models

 

[Frank Mopar]

You start the vehicle and spray the manifold with give it a good spray with soapy water. Matters not if the manifold is hot it will still bubble at the leak.

 

[WileERobby]

 

[gkent]

Drive that patato in there hard and far. The leak will be found in short order. But expect a good boom to go with it. Now we have a leak.

Hell, don't stop there, shoot some spray foam in there !!

 

[Nxcoupe]

I saw on YouTube yesterday someone was checking for exhaust leaks by adding pressure to his exhaust system by switching his vacuum hose on his shopvac to the exhaust outlet and then shoving the hose in the tailpipe. He then simply sprayed down all his exhaust joints with soapy water and looked for leaks, similar to checking for leaks in a tire. For a dual tailpipe situation, you stopper the other tailpipe. This looked like a ridiculously easy way to check for leaks without working around a hot exhaust system. Are there any dangers to your engine in doing this? I can see where a valve or two may be open into the heads at any given rotation of the engine, but it is not like there is much air flow that will be carrying particles, more just air condensing and building to pressure. I don’t want to risk damaging my engine, but it sure looks like an easy way to check for leaks…….am I missing something?….. What are your thoughts?

That is an excellent way to do this. I instruct techs to use the smoke machine we use for evap checking and put the adapter in the tailpipe. Then turn the machine on and look for smoke. Using the vacuum's exhaust side to pressurize and then spray soapy water on all the joints is an excellent idea. Good luck with it.

 

[moparedtn]

Seriously? Sheesh, get you a couple thick rags and get back there with the engine running.
You'll hear any leaks in short order.

 

[Nxcoupe]

Seriously? Sheesh, get you a couple thick rags and get back there with the engine running.
You'll hear any leaks in short order.

Yes, seriously. It's much more precise, and time is money.

 

[Frank Mopar]

Start the car and spray soapy water. Nothing else needs to be done. Works on hot engines too. Spray away!

 

[KENTON]

Any dirt or rust scale tn the exhaust is going into a cylinder with an open exhaust valve.

 

[moparedtn]

Any dirt or rust scale tn the exhaust is going into a cylinder with an open exhaust valve.

Yep, I want that exhaust going the correct way no matter what method is employed.
Sometimes, exhaust isn't just spent gases.

 

[mopar 3 B]

Who the heck needs an exhaust anyway?