Exhaust/Manifold Crack and Leak - Any Potential Damage? How Urgent to Fix? (3 Viewers)

[04UZJ100]

I have began to hear a tick during the initial crank/fire of the 2UZ in my 100 series. After about 1 second of audible ticking, it cannot be detected at idle anywhere around the car. The tick is then noticeable when driving under light acceleration until the car warms up. What's confusing, though, is that the tick cannot be heard when revving the engine in Park after the engine turns over - even when cold. It's only audible when driving while the engine is warming up or on the initial fire of the engine like I mentioned.

I crawled around the truck today and although the frame is in near perfect condition, the exhaust has seen better days. Many of the flange bolts are corroded to the point of not longer having sides. What is the best way to troubleshoot/identify the source of something like this? What's the best way to find potential exhaust leaks? I do not believe it is a header leak simply because of the year of my truck and the fact that it is not audible when walking around while the engine is running.

It's driving me nuts!

Thanks in advance!

 

[04UZJ100]

Based on some further search and the fact that I did not want to be in denial - it appears I have the infamous exhaust manifold leak/tick......what are the potential issues with running the truck like this? The noise seems to go away completely once warmed up although there is an extremely slight tick when driving next to something like a jersey barrier.......?

 

[JunkCrzr89]

Double and triple check that you don’t have a spark plug that’s walking out and about to ruin a head.

 

[04UZJ100]

Plugs are tight. Replaced them after 120k in 2019. Checked again in 2021 and again this morning. Only took 20 minutes so getting good at it.

 

[94SRUNNER]

Plugs are tight. Replaced them after 120k in 2019. Checked again in 2021 and again this morning. Only took 20 minutes so getting good at it.

Are you checking to a specific torque or just by feel?

 

[04UZJ100]

Are you checking to a specific torque or just by feel?

I went by feel today. Didn’t take the torque wrench out.

Checked to 16ft-lb last time. Boots on coil packs were pristine too. No indication of thermal degradation.

 

[Montymitch]

What you described is exactly what I experienced with my 2000 lx470. While mine wasn't causing problems other than noise, it just got worse and worse until I installed new DT headers. The manifold expands at the crack when the engine gets warm, so the ticking is less noticeable. I've had my headers for about a year and they are trouble free.

 

[abuck99]

To answer your question yes a leaking log will create a condition where your ECM thinks it’s running lean and will add more fuel- this will increase consumption but over time will kill your cat converter.

Check fuel trims -they should indicate rich if there’s an exhaust manifold leak-

So fix the manifold if it’s actually leaking- pull it and check the welds- or take it for weld testing if you can’t see a crack ( usually where the flange is welded)- also could be the gasket. Strange if it is a log leaking though as 04+ rarely had that issue- just earlier years I think.

 

[vipergrhd]

^^^ This and if you could get a smoke machine and pump it to the exhaust system. Look for exhaust trails too around manifold.

 

[awesomeissquid]

Another way to perform the testing is to get a shop vacuum and put the hose on the outlet and connect it to the tailpipe. With it blowing air into the system you can spray some soapy water around the entire exhaust pipe length to identify any leaks (pretty simple to see since they will bubble up).

 

[04UZJ100]

Another way to perform the testing is to get a shop vacuum and put the hose on the outlet and connect it to the tailpipe. With it blowing air into the system you can spray some soapy water around the entire exhaust pipe length to identify any leaks (pretty simple to see since they will bubble up).

Genius. Thanks!

How do you recommend inspecting around the manifolds themselves due to heat shields etc?

 

[awesomeissquid]

I would remove the bolts for the heat shields. Each is held by 4x small bolts (10mm if I remember correctly). Be sure to use penetrating oil since they can be a bit stuck.

 

[Phallen]

I also have the infamous ticking. I saw a pretty good video by ChrisFix on YouTube on how to locate exhaust leaks and how to repair them. Now, I know it won’t be permanent fixes but it is a temporary solution,.

 

[awesomeissquid]

I also have the infamous ticking. I saw a pretty good video by ChrisFix on YouTube on how to locate exhaust leaks and how to repair them. Now, I know it won’t be permanent fixes but it is a temporary solution,.

I watched that video as well before I tackled mine. Most of the cracking on ours that causes the ticking is right where the flange of the exhaust manifold is covered by the mounting plate. It is likely that you would need to remove the manifold to properly attempt the repair and at that point you are better off swapping it out.

 

[04UZJ100]

I am not opposed to trying this:

 

[Phallen]

I am not opposed to trying this:

It looks promising. Let me know how it goes.

I watched that video as well before I tackled mine. Most of the cracking on ours that causes the ticking is right where the flange of the exhaust manifold is covered by the mounting plate. It is likely that you would need to remove the manifold to properly attempt the repair and at that point you are better off swapping it out.

You’re right.