LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

Flappy blowy engine noise

Old 05-18-11, 04:14 PM
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deanbrown
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Default Flappy blowy engine noise

Greetings.

I've had this valve-train-like noise for a few years now on my 96LS (240K) and it's getting worse and worse - it sounds like something is blowing or flapping when I let off the gas (standing next to the car, that is). I heard about some kind of recirculating exhaust pipe part, but I need more info on this (such as what it's official name is in these forums). Can anyone elaborate on what the part does and how to go about fixing it? Or better still show me a picture of the thing. Sorry if this is a dumb question but I have searched and searched but I still don't get what's going on.
Old 05-18-11, 04:32 PM
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LSproject
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I believe its most likely an exhaust leak somewhere. My car is having the same problem and I'm going to take a look at it in a couple of days before I smog the car. Could possibly be the gasket from the block to the headers could have shot out, or from the header to the cat,
Old 05-18-11, 04:47 PM
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deanbrown
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Wouldn't there be an engine code in this case? I had codes when the exhaust rusted through just before the first cat.
Old 05-18-11, 05:12 PM
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deanshark
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I think you're thinking of the EGR pipe. It's known to crack. I don't recall if it throws a code, but I don't think it would. There are alot of threads on the subject about how hard (or easy) it is to change. Here are a few. https://www.clublexus.com/forums/sea...archid=6608796
Old 05-18-11, 07:41 PM
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sdls
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your lower EGR pipe is broken.
Old 05-18-11, 08:56 PM
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deanbrown
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Are there two of these or just one? I only ask because there are two listed on ******* for this engine:

25601 PIPE SUB-ASSY, EGR, NO.1
25601‑50060 1UZFE..UCF20..4FC 1 $122.72
25601J GASKET(FOR EGR PIPE, NO.1)
25634‑50010 1UZFE..UCF20..4FC 1 $5.61
25602 PIPE SUB-ASSY, EGR, NO.2
25602‑50010 1UZFE..UCF20..4FC 1 $116.95
25620 VALVE ASSY, EGR
25620‑50030 1UZFE..UCF20..4FC 1 $454.52

The site is t-o-y-o-d-i-y but for some reason it won't accept this link.

Last edited by deanbrown; 05-18-11 at 09:02 PM.
Old 05-19-11, 11:53 AM
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steve2006
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It's normally the lower pipe (25601-50060) that breaks at the concertina section,there have been success stories where the break has been welded but considering the pipe is quite difficult to remove and refit replacement may be the best reliable long term solution.
Another point raised was the break could be as a result of worn engine mounts causing excessive flexing of the pipe so it may be worth checking these as well.
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