That sounds like an exhaust leak to me, a pretty good one. I can't tell anything else about the motor, even on my good headphones.

It was probably louder because you cold started your car, so the idle was high.

 

yeah, unfortunately the previous owners did a crappy side exit so its pretty loud. I wanna get it redone out the back, although it does sound amazing

 

Oh it already has cut pipes. Yeah you need to record way better audio for us to be able to tell if the motor is making weird noises.

 

dont know how id do that to be honest

 

You can upload and share a video very easily on these platforms.

Also, it looks like you're missing the aero shrouding under the engine - but I'm curious what these are.

 

yeah, the previous owner took off whatever skid plate there was, and a bunch of plastic shrouding under the vehicle. The underside of the bumper is very accessible on the passangers side. They kinds just ripped stuff out to be honest

 

Yes. Definitely sounds like a leak . Though the exhaust having been tampered with makes it difficult to tell. Mine developed a leak after the CAT at the gasket and I patched it with some thin stainless steel sheet metal, some ceramic paste and a few stainless large hos clamps. The other leak that has developed was a number of small pinholes in the Y- tube behind the cats. Same fix. Both fixes has held up well several years now.
That the valve cover needs new gasket is common I have been told. My LS leaked very slightly from there.
I just retightened the screws that ALL were a bit loose. Seems fine for now,

 

Is there a service manual or step by step procedure to remove the engine for the LS400 (for those of us who've done it on different makes)?

 

The attachment is for a 1998 LS400. Different chassis may have slightly different details.

 

Check out this video- its for a LS430 engine and transmission combo, but in it he makes reference to and shows the factory manual with illustrations for extracting the engine and transmission together. I don't have a LS400 manual so can't direct you to the proper pages of it, maybe someone else can. If nothing else, the video is informative and entertaining and filled with lots of the issues you can expect to face and some of the tools you will want to have. He calls it a "mammoth" undertaking at the end.

 

Thank you. I take it this is from the factory service manual. Is one of those available to buy? I would like to get one, since I need the torque specs to reinstall everything.

 

Yeah, it looks like a couple days worth of work. I can take the engine out of my C4 Corvette in two days, but it does not have all the wiring and plumbing I see on this engine.

 

Deleted for reasons

 

Bro. It's not even a difficult swap. At worst it's a 5 outta 10. I can walk you through it if needed. But only if you take pics of the B2S1 O2 sensor connector and it's wiring so I can repin mine 😂 😂 😂 😂

 

Did you are someone else ever remove the camshafts? The exhaust cam has a spring loaded gear that makes noise if it loses it's tension.