Gsxr6k6

You mentioned you had recall work done and I have the softening of the interior door panels under hot conditions. I've heard of some ppl getting it taken care of through warranty. I had a IS350 that had a similar issue on the dash.

MpKSonic

This video wasn't shot with the intention of listening for a potential broken exhaust manifold/leak, but I figured it's worth a shot to share here and ask those with a more in-tune ear.

Is anyone able to hear an exhaust leak?

I'm asking because I have an extended warranty with the car, and the exhaust manifold is covered. I'm curious how this process would work with the warranty. Should I contact the extended warranty company and state that I 'think' I have an broken exhaust manifold and see where they take it from there? Or should I pay for the diagnosis myself, (I'm sure not too cheap), and come to them with proof?

My ultimate goal, if possible, would be to purchase aftermarket headers, (I'd assume my cost), and have the warranty company pay to have them installed under the warranty. Has anyone gone a similar route to this?

Lastly, the previous owner was pretty certain the car had a broken exhaust manifold, yet he had the starter replaced at Lexus just before I bought it and the stock exhaust manifolds were left in place. Leads me to believe they were normal working condition.Or he knew he was getting rid of the car already and just wanted it in working condition so that he could trade it in and not spend any extra money.

lobuxracer

iTrader: (2)

If there is a leak, the best way to hear it is on cold cycle under load. Often what happens is the crack seals up once the manifold gets hot and makes it very difficult to hear, but when the engine is cold, it's usually pretty loud. You don't have to beat on it when its cold, if the crack is leaking you should be able to hear it on moderate acceleration from a stop. Most of the time it's only one cylinder that is leaking so the sound is distinctive.


Skip forward to 1:20 to hear the sound. This is a very good recording of an exhaust header leak.

ThomasGS4

iTrader: (19)

Anotha' one!

steeven001

Another one. Passenger side typical spot they all crack in. I cleaned mine up and welded it back together and reinstalled. I forgot to take a picture after welding it because it was getting late and I still had to put everything back together and do an alignment.

samjones

iTrader: (1)

Same here

Gsxr6k6

Dang, good job. That's a lot of work.

BlckGhst

Those who have welded the OEM manifold - you used new gaskets or reused old ones?

67mattbo

McPierson

iTrader: (3)

I'm a decent welder for being self taught. I have a nice mig and I have access to a TIG (never used before). I've always wanted to have a reason to learn to TIG, but I don't want to spend 40hrs practicing to save $100. I've got a lot of stick welding and soldering experience. I'm not just a MIG wannabe.

I've not welded much thin-wall. I did make a custom y-pipe several years ago. I still have some material to practice on. Should I get some practice, or should I just take it to an exhaust shop after it's off the car? I guess what I'm asking is... of the people who have actually personally welded this (I don't need any feedback from people who don't weld) what skill level do I need to accomplish this? I REALLY don't want to do this twice. I acknowledge that there's a risk even an exhaust shop repair would fail. On some level I think that I would rather weld it because the consequences of failure fall on me, not them. On the other hand they weld this stuff all day every day.

Thanks in advance.

BirgeyT1

This one isn't actually cracked right? That's just the floating flange. The little lip that holds it in place against the flange is actually the part that cracks off if I'm understanding correctly.

steeven001

If you've welded exhaust pipe before you'll be fine. You could practice welding a piece of exhaust pipe to a 1/4 - 3/8 thick flang to get a feel for it so you don't blow a hole in the pipe. I'm no pro welder but it came out good enough to last I highly doubt it would ever crack again.

But if you don't feel comfortable I can't see an exhaust shop charging more than $20 just to do a 5minute weld if you bring it to them all cleaned up ready to go.
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From all the pictures I've seen I've never seen a crack on the driver side manifold. People have said their driver's side cracked but they didn't do the work themselves so they're just going off the lies the dealership tells them. It's always the passenger side cylinder 8 that cracks. That part the pipe is welded to the flange and cylinder 6 the flange is floating.

BlckGhst

I'll be removing mine probably sometime next month. Got a quote for $50 for the repair at a welding/fabrication shop. Gonna throw in new gasket and a starter too while doing this

McPierson

iTrader: (3)

Thank you Steeven. I'll go with that.

Next question: I don't have a lift. My plan is jack stands and an engine hoist to support / lift the engine. Is that going to be a problem?

Next next question: Should I just plan on replacing the O2 sensor? / what's the chance of it stripping/galling and getting stuck requiring me to cut the wires and use heat to remove it off the car?

TYIA

steeven001

I was a mechanic for 12 years and I personally wouldn't want to do this on the floor but I would do if it I didn't have access to a hoist. It's still very doable and if you're just removing the passenger side manifold it's not too bad you have less to take off.

Your working angles will be limited with your arms and tools when you're on the floor so you'll want to completely remove the subframe to work comfortably. Here's a quick run down that will help when doing this on the floor. This is just for doing the passenger side manifold. Keep in mind I never did this on the floor but I did do it on a hoist 2 weeks ago and it wasn't that bad like a 7/10 difficulty.

I would expect to take almost 10-12 hours if you're doing this on the floor

Parts I used: manifold gasket, manifold nuts, dipstick tube o-ring and exhaust manifold to ypipe donut gaskets

1. Remove distick, dipstick bolt, and dipstick tube. If tube doesn't come out you can get it out after with pliers and a hammer.
2. Raise vehicle off the floor with enough space to work comfortably underneath. Remove front wheels. Remove engine under covers.
3. Remove rear o2 sensors, use breaker bar or heat if needed. If they won't budge disconnect the connector from under the floor mats and leave the o2s connected to the exhaust. Pull wires through the holes in the floor. Remove exhaut y pipe/mid pipe
4. Support engine with Jack stand + block of wood, or engine hoist from above
5. Mark subframe bolts so they go back somewhat in the same place. Unbolt lower control arms and pry away from subframe
6. Unbolt steering rack from subframe and pry away and tie up so it doesn't hang
7. Unbolt motor mounts from subframe
8. Make sure motor is supported for your own safety you don't want this thing to fall on you.
9. Remove remaining bolts for subframe slowly back off each one at a time until it stops moving then take them all out. Check that steering rack is tied up good and detached from subframe
10. Get a helper to help pull the control arm away on each side so you can get the subframe to drop and get it out of your way. Put 2 wheel nuts on to hold the rotor down and they can pull on the rotor.
11. Remove passenger side motor mount and bracket
12. If you didn't get the dipstick tube out hold it with some pliers at it's base where it's in the engine and hit the pliers with a hammer and it should pop out.
13. Remove manifold heat shields.
14. Remove manifold, clean it, weld it
15. Install new manifold gasket
16. Install manifold and torque it down using repair manual sequence.
17. Reverse removal. Remember to preload your control arms with a Jack before tightening the bolts for the 2 bushings.

I highly recommend an alignment after you do this because it's hard to get the subframe back to where it was so your alignment will be out of spec. When I did mine I end up with -1.8 degrees camber on the driver side and -0.7 on the passenger so I had to shift it over a little to equal it out