Klierslc

Pretty much like it says, when first starting up and driving in the morning, any throttle use gives me a small exhaust leak noise from the front of the car. Once it is warmed up ~5 min or so of easy driving, it goes away. Search didn't turn up much, but I was curious if anybody else has/had this same problem and where it was specifically.

I am thinking that it is a warped manifold that trues when it gets hot, but I don't know much about these things. If that is the case, should I just re-torque the manifold while it is hot, or will that damage the head?

I'd like to replace the exhaust gaskets while I am in there, but if re-torquing will solve it, I won't bother with the risk of taking off the rest of the bolts.

Thanks for any help or comments,

Dan

steveski

Actually there is a small diameter aluminum/metal pipe at the back of the engine where exhaust gasses recirculate (I am pretty sure). I bet you have a very small pin hole in yours and when it heats up, the material expands thereby closing the leak. I had the very same problem onm y 1995 and eventually it leaked all the time and it literally sounds like an old junker car you hear on the freeway with a bad exhaust. If it truly is that little pipe, changing it is a bit of a pain but well worth it because it will not get better over time. I have a factory manual and will look it up if you like and PM you the details.

steveski

Here's an older link that discusses it:



https://www.clublexus.com/forums/sho...light=EGR+tube

Klierslc

Thanks,

I saw quite a few mentions of the EGR pipe when I was searching, but I was hoping that wasn't the problem. I guess I'll know more when I actually open the hood.........

sonyman

Put some seafoam in through a vacuum line one night. Leave the car. The next morning, open the hood and start it up. You may be able to see the seafoam smoke at the leakage point.

steveski

I hope it isn't the EGR pipe either but when I read your post it made sense since my car did the same thing. I too thought it was the manifold and to my luck it wasn't. I don't even think it is visible under the hood but who knows. Let us know how it turns out.

steveski

Seafoam is the good stuff

Klierslc

Well,

You guys were right. I pulled the EGR pipe off and there was a pinhole and a crack. I brazed it back together and then added a couple layers of muffler tape to insure against any further breaks. Buttoned it back up and she is quiet as can be.

I did break off two exhaust studs from the manifold flange where the cat bolts on, but the manifolds are extremely hard, so after extracting the studs and chasing the threads with a tap, the threads were in great shape. I just picked up new studs at the hardware store, and off we went.

Anyhow, thanks again for all the help