Hi folks,

My recently acquired 1992 LS400 has an exhaust leak right behind the engine on the driver side. My research (which is mostly on this fantastic forum) tells me that an exhaust near the front of the LS400 is usually due to a cracked EGR tube, however I think I can rule that out considering that the EGR tube is on the passenger side.

I found this leak by putting a bit of Seafoam through my brake booster vacuum line, exhaust not only came out of the rear pipes but also from right behind the front driver side wheel. Are there any flanges in this area that could have been rusted out?

Picture of the LS!

 

I thought things didn't rust in that state? All I see is solar paint distress.

 

The catalytic converter flanges usually leak.

 

Can confirm- the cats near the front have a tendency to bow their flanges as well as the flanges on the exhaust pipes. I put my LS up on ramps, heated the flanges red hot with an acetylene torch and pounded them back together, then replaced the donut in between on both sides. No problems since. Weird design flaw, and it doesn't happen to every LS, just the lucky ones I guess.

 

Yeah I got one car that someone welded a leak on the bottom, and will be a pain to of course cut out.

 

Nice looking 1991. Welcome!

As a side note, your rims are backwards. Your front left wheel is a right rim. This tends to happen when a shop does the tire rotation; however, you'll notice the rims have a printed L or R on them to indicate which side they should be on. This was designed to increase brake cooling.

 

So, no rotating tires from side to side on the early ls400's?

 

Correct. It's just front to back and back to front for each side. No criss-crossing of the wheels. You can do it, but it won't be as good for brake cooling.

I really like the 1990-1992 rims though, so it doesn't bother me.