GS - 2nd Gen (1998-2005) Discussion about the second generation GS300, GS400 and GS430 (1998 - 2005)

Bad exhaust manifold?

Old 11-14-13, 07:29 PM
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DMPesso
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Default Bad exhaust manifold?

What's up CL! I have an 01 GS430 and I was about to change the exhaust manifold gaskets for a whopping $1000 in labor because the rattling ticking noise was annoying the fuxk out of me. Now before the mechanic did it I told him to make SURE that's the issue because I'm not trying to blow a G to come to find out that's not the issue. Now since he's an honest guy he called me over and said the mechanic said there is no way to tell if it's the gasket or a crack in the manifold itself. So he said if yor spending $1000 you might as well change the manifolds on both sides to be sure otherwise it's not worth the risk if it's not for sure gonna fix it. Now that's another $800+ for the manifolds and what he said was since the noise is mostly noticeable on the drivers side he said if I want to save money maybe change the drive side manifold. Now I need some serious opinions please on what you guys think if you guys ever seen these manifolds or gaskets go bad and what everyone thinks is most likely the issue and what they would do. I'm in a ****ty situation need some help! Especially because basically the whole suspension is new everything else on the car is perfect so it sucks to hae such a nice car sound so ****ty when you press the gas. Thanks everyone!
Old 11-14-13, 08:19 PM
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Dawa
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i dont know why a 'bad exhaust manifold' would cause a rattling or ticking noise? is this a common problem? what is supposedly bad about the mani?
Old 11-14-13, 08:32 PM
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MasterKwan
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I bought a pair of used manifolds off ebay for $225. They were perfect. From an SC430.

I'm doubting your manifolds are cracked. Honestly, I'm skeptical about the exhaust manifold gaskets because they're steel multi-layer gaskets and are 100% re-usable. I'd be more inclined to think the manifold to cat gasket blew out.

It's a hella job replacing the manifolds and gaskets. I had to drop the engine out of the car to remove and replace mine (for other reasons, not cracked or leaking).

I'd get two people to plug the tailpipes with rags and see if it feels like it's leaking exhaust. If it is, I'd get it into the air and repeat the process while someone moves forward and listens for the leaks.

Did you tell them to replace the manifolds or ask them to find the leak? If you tell them to replace them, they will even if it doesn't solve your problem. You should never tell a mechanic what's wrong, you should let them figure it out and then tell you. Then you can decide if you believe them or not. Honestly, even if they were cracked, they're just stainless steel tubing. They can be tig welded.
Old 11-15-13, 09:04 AM
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I was thinking that too but I didn't guess that supposedly was what they narrowed it down to when they checked it a long time ago.
Old 11-15-13, 09:05 AM
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And no I didn't tell him to just replace it. He diagnosed it a long time ago and I finally went in and said check it on more time if your sure it's the problem I will spend the $1000 labor now to pull the engine and change the gaskets. Come to find out he said it could have a chance of being a cracked manifold
Old 11-15-13, 09:08 AM
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But I remember when we checked it the noise sounded like it was above the cat from the gaskets/manifold area I think that's why they said it wasn't the cat gaskets
Old 11-15-13, 09:29 AM
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Cars break and I'm sure manifolds crack. Having had two sets of manifolds in my hands in the past week or two, they just didn't seem crack prone. Have they ever been off before? I'm just wondering if they're loose.

When I did this, in my shed, I lowered the engine to the ground by disconnecting the engine cradle and hooking a hoist to the engine. That would certainly be cheaper than pulling the engine completely out. I didn't even have to disconnect the transmission from the engine. I just disconnected the peripherals and lowered them as a unit. If I had a lift it would be been even easier. I just lowered it enough to clear the frame rails and worked from the sides to remove them.

I'd look in ebay for manifolds before I bought new though:

17104 1710450160 MANIFOLD SUB-ASSEMBLY, EXHAUST, RIGHT. MANIFOLD SUB-ASSY, 4300CC 32-VALVE DOHC EFI; GS430 (UZS161) $342.60 1710450160
17105 1710550160 MANIFOLD SUB-ASSEMBLY, EXHAUST, LEFT. MANIFOLD SUB-ASSY, 4300CC 32-VALVE DOHC EFI; GS430 (UZS161) $342.60 1710550160
Old 11-16-13, 06:06 PM
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They haven't been off as far as I know but who knows anything can happened especially with NYC roads. I'm having a mechanic do it for $700 plus an extra $75 for used manifolds if I end up needing them. Much better then the 1000 I was originally gona spend at the first mechanic. It is a big job taking out the engine so $700 is a fair price right? It's over a days labor supposedly.
Old 11-16-13, 06:08 PM
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And as far as manifolds since they're not necessarily wear and tear I will probbaly go used since spending 7-800 for a set of manifolds is crazy
Old 11-16-13, 08:42 PM
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Much better then the 1000 I was originally gona spend at the first mechanic. It is a big job taking out the engine so $700 is a fair price right? It's over a days labor supposedly.
I thought $1000 was fair. It's a miserable job. Hopefully the cheap guys do a good job.
Old 11-17-13, 12:08 AM
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Originally Posted by MasterKwan
I thought $1000 was fair. It's a miserable job. Hopefully the cheap guys do a good job.
Oh good now I feel even better about that price. Yea the cheap place only works on Lexus and removes engines often so I should be good on that note it's just a different neighborhood that shop isn't nearly as busy as the one that wanted $1000 next to me in Brooklyn but it's worth the drive. I'm praying everything works out perfectly !
Old 03-13-14, 09:07 PM
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Just incase anyone else experience the same farting noises among cold start and driving slow it was fixed by changing the driver side exhaust manifold. The car is more powerful now as well I can even hit almost near redline which I wasn't able to do before. I guess the tiny air leak messed up the compression. The car is much more responsive now. This only happens on 430s not 400s since Lexus changed the design of the exhaust manifold. And the engine just needed to be tilted not physically removed. The guy did it in less then 8 hours! Back to the butter smooth quiet Lexus!
Old 03-13-14, 09:22 PM
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Damn... for having to do that much work, you should've just saved up a bit more and added the PPE headers But, happy that it's running well again.
Old 03-14-14, 11:28 AM
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I would've but I wanted to keep everything stock to avoid future problems. I got the manifold used for $75 so I can't complain. Old one didnt look like it has any visible holes. Maybe it was just loose? Don't know how that can be. And by the way anyone know if he had to lift the engine and tilted it did he remove any steering components like ball joints steering rack or anything that would make me need an alignment?
Old 03-14-14, 05:46 PM
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I know exhaust manifolds on lx470s and crack causing the noise you are talking about. To replace just one was $1700 so the price you are getting seems reasonable

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