An Exhaust Problem

[krew]

Hi all,

I've noticed my '94 LS400 has been quite a bit louder on start lately. At first I thought it was just the cold winter, but a couple days ago I started up the car and found that exhaust was escaping through a slight separation in the exhaust joint closest to the engine. I took a photo:

The exhaust stops escaping and most of the sound goes away after the car warms up, but the car still sounds louder when accelerating.

My questions are:

* Is there a gasket in this joint? If so, where could I find the part #?

* Would this slight seperation make the car sound louder?

* It looks to me like all this needs is to be taken off and reattached using new bolts, it doesn't seem like the exhaust is damaged -- has anyone experienced this before?

* How long would it take a compentent mechanic to remove and reseat this? Any tips I should pass along?

Thanks in advance for any help you can give me.

[92Lex]

Yes, there's a gasket between the two exhaust flanges.

Yes, a slight seperation would cause your car to sound louder. Are you positive that it's leaking there though?

It's recommended to replace the exhaust flange bolts but it's not absolutely necessary, though.

It takes about 10 minutes to replace that gasket.

[krew]

Thanks so much for your response, 92Lex, much appreciated.

I'm almost positive that the exhaust is leaking between the flanges. I saw white exhaust right from the seperation, which disappeared after a minute or so, though I could still see a bit of heat shimmering. The exhaust pipes look quite good, with only some surface rust.

To get the parts I need, I was planning to just go to Lexus and explain it to them, then bring the parts over to my trusty mechanic.

Another thing I'm wondering out of curiousity, what would have caused this, just wear and tear?

[LScott400]

Yep. Intense heat causes cracking and deterioration.

[SKperformance]

Use some seafoam to look for other cracks or damage in the exhaust.

[LScott400]

Use some seafoam to look for other cracks or damage in the exhaust.

You've got that right! Seafoamed a '91 Stealth this weekend and almost wet myself when smoke started pouring out of the front of the engine compartment. Turned out to be a burnt gasket on the downpipe off the exhaust manifold.

[SKperformance]

Have found many a car leak when it was never know ,while using seafoam it shows quite easily escaping through all sorts of places..

[krew]

Thanks for the advice, I'll update with the results -- I'm going to capture the seafoam treatment on camera. Should be an interesting photo!

[denkigroove]

Hi all,

I've noticed my '94 LS400 has been quite a bit louder on start lately. At first I thought it was just the cold winter, but a couple days ago I started up the car and found that exhaust was escaping through a slight separation in the exhaust joint closest to the engine. I took a photo:

The exhaust stops escaping and most of the sound goes away after the car warms up, but the car still sounds louder when accelerating.

My questions are:

* Is there a gasket in this joint? If so, where could I find the part #?

* Would this slight seperation make the car sound louder?

* It looks to me like all this needs is to be taken off and reattached using new bolts, it doesn't seem like the exhaust is damaged -- has anyone experienced this before?

* How long would it take a compentent mechanic to remove and reseat this? Any tips I should pass along?

Thanks in advance for any help you can give me.

when the sound is going away thats the gasket expanding under heat. honestly what i would do is pay an exhaust shop to cut the flanges off and weld it together. solve your problem and reduce a pound or so in flange weight even sell them later if you need it. will cost 5$ and a couple of minutes. or even wait 10-15 minutes and have them rid of all the flanges heh

alternative is to buy a gasket from a store for a couple of dollars new bolts (usually exhaust bolts are pretty rusty and need replacement) and do it yourself... would take a few minutes if you have the proper tools (jackstand, wrenches, jack) and you might get a bit dirty... (when there is a leak a lot of carbon will spew out)

[SKperformance]

You don't weld that point as it uses a dough nut gasket to allow for play form the engine .

Just get new gaskets and be done with it in 10 minutes.

[92Lex]

You don't weld that point as it uses a dough nut gasket to allow for play form the engine .

Just get new gaskets and be done with it in 10 minutes.

Exactly

[djspawn00]

As with any exhaust testing.. make sure you're outside.

[krew]

A few things have happened since I posted this problem:

* I took it to my mechanic and had only the one side reseated with a new gasket (he told me the other side was perfectly fine).

* Noticed an absolutely amazing difference in noise level, how can a little ring make such an impact?

* Last week, I noticed the other side was now making noise, and made an appointment to have it fixed. Before I took it in, it was cold out and I noticed exhaust escaping from BOTH sides, even the one that had been fixed already. My mechanic fixed both for free and used a high-temp sealant to make the seal even tighter, and the noise is way way down with the car (so much so that I'm noticing new noises!).

* Problem is, when going over the previous owner's service records, I noticed he had the same thing done at 70k (the car's now at 90k). This got me worried, as it seems like a potentially larger issue.

I read at this link: http://www.clublexus.com/forums/showthread.php?t=143739 about a similar problem and it was caused by a blockage in the Y-pipe -- thing is, I'm not experiencing any power loss at all, and the car's running smooooth.

Can anyone give me an idea of what else could be causing this flange seperation?

PS. As an aside, I had this entire problem fixed at my mechanics for $25 -- the previous owner paid $300!! Thanks everyone!