1999 Rodeo V6 MT - Exhaust leak - common areas?

Hey Everyone,
I have an exhaust leak that's proving tough to pinpoint. It's not that noticeable until the car is moving/under load. I thought that it might be the flange gasket on the driver's side exhaust manifold, but replaced it to no avail. I'm still trying track it down. It seems to be near the front of the vehicle, but I may have to use a mechanic's stethoscop with some tubing attached to it to try and locate the source.

Does anyone know if there are certain locations on these vehicles that are prone to leak (exhaust manifold, O2 sensor?) It's a '99 with 110K miles on it.

Does anyone know a good way to detect exhaust leaks? I don't have an emissions wand, so...........

Any input appreciated.

Mark
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Check the flex pipe on the passenger's side upstream of the "Y".

if that is the case, there is a new product out that is suppose to be superior to the flex pipe. i've seen it in 4x4 mags. i'm just waiting for the pipes to fail so i can get it. it is a flex pipe that is made for 4x4 so it stands up a lot better and is a heavier duty material.

check the seems around the cats, they can break if you bottom out on a curb, rock or small child....

Thanks I'll check that flex pipe and the seams around the CAT's as well. Much appreciated. I'll report back with what I find.

Thanks again,
Mark

I checked out the areas mentioned, the flex pipe and the CAT welds, but then realized that after I had replaced the driver's side exhaust flange gasket, the leak was even louder. Troubleshooting techniques of course led me back to what I had touched that made it worse. I spent time looking up at the flange and could see a small amount of carbon around the weld that holds the pipe to the flange. I then surmised that the torque I had subjected the flange to likely loosened up the leak even more. The carbon showed around approx. half the circumference of the pipe, the ring of it being maybe 1/16" wide. It was getting louder by the day.

I decided to take the pipe down to check it out. In order to get the driver's side pipe out once it was disconnected at both ends, I had to take off the transmission mount while supporting it with a jack of course, and also had to take off the torsion bar which proved to not be too difficult as long as its indexed it at 3 points (one at each spline end and a thread count at the top of the carriage assy and is done with the vehicle jacked up/no weight on the tire). Quite a bit of work just to get the pipe out. I also had to change out one of the flange studs, which went smoothly as well and required using an E-12 Torx socket.

Once I had the 4 foot section of pipe out, I found a hairline crack at the weld and could see daylight through it. Got it welded and now it purrs like a kitten.

I would like to point out that there is a HUGE difference between the exhaust flange gasket sold by the dealer and by the aftermarket outlets. It costs $25 at the dealer and anywhere from $3 to $12 at auto-parts stores. Save yourself time by getting the one from the dealer. The difference in quality and fit are HUGE.

Thanks for your input.
Much obliged.
Mark
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glad to see that everything worked out for you.

the dealers always mark up the prices...

glad to see that everything worked out for you.

the dealers always mark up the prices...In this case the price difference is probably because the after-market gasket is a P.O.S. paper style gasket whereas the OE one is a "flexitallic" style spiral gasket.

http://www.apservicesinc.com/images/flexitallicgaskets.jpg

Exactly as Steve points out. Get this part FROM THE DEALER. The aftermarket gaskets are P.O.S. as Steve pointed out. This is not something you want to save $15 on since replacing it isn't easy.

Mark

Now my starter is acting up a bit. Over the past 11 days (I'm keeping a log), there have been 4 instances where the first 2 tries yielded either a faint clunk or silence, and the 3rd try produced a nice strong start. My theory is that the starter internals (brushes, bushes, solenoid, armature shaft etc...) are worn after 111K miles and probably 4K starts, and occasionally it stops at a bad spot where the brush contact is bad, or the shaft is off center and can't provide the torque, or the solenoid isn't able to actuate fully or make the electrical connection.

You get the picture. Is the starter easy to access/replace? The shop manual shows that there are only 2 mounting bolts. Of course I'll check for loose connections etc. first.

Is it easy to get brushes and replace them?
Anyone?

Thanks,
Mark

The starter is super easy. Disconnect battery terminals, leave the electrical to the starter until you have it loose. Pull the two long block bolts--a little tough as you can't quite go straight up and in, but you can get it if you work at it. Then just drop the starter and pull the electrical once you get it clear. It helped to put the car up on stands so the tire on the driver's side drooped and gave me some extra clearance. Surprisingly easy job, compared to the alternator . . .

sm

Yeah, your right. I took it off. Pretty easy, a small heat shield held on with three 10mm bolts, and then just the two 14mm bolts that hold the starter in, the 12mm nut that attaches the battery cable, and the little connector for the solenoid.

I opened up the starter completely and inspected the pinion gears, brushes, bearings, armature, commutator, and solenoid plunger. Everything seems in order except that there was a LOT of pitting on the plunger and starter surfaces where the main power comes through to the starter motor when the plunger pulls back sending the bendix gear out to the flywheel. I used a very fine polishing wheel in my dremel tool to smooth up all of those copper/brass surfaces. I think that that may do it.

It had come to the point where I could hear the starter engage the flywheel on the first attempt, but it just couldn't produce the torque to spin the flywheel. All of that pitting could very well be the problem since all of that loss of surface area likely cut down, just enough, on the amount of current that could be conducted across them. With all of those amps traveling through there, I guess there's no getting away from it pitting too much eventually.

Now I'll reinstall it and see how it goes. If it hesitates again, I'll replace the starter.

Thanks for your input. Much appreciated. I'll add an update once I've reinstalled it and checked it out.

Thanks again,
Mark

Well, that was fun, but it didn't work. I ended up having to replace the starter today. It's been quite a month: replaced the stabilizer bar links, fixed an exhaust leak, and replaced the starter. Hopefully, and I shouldn't say this, that'll be it for a while.

I appreciate all of the feedback. This forum is great. I've had man phone-calls and e-mails from many people whom I've had the pleasure of talking through repairs that I've written procedures on and posted, especially the one concerning the fuel pressure regulator.

See you all in the near future I'm sure.
Mark
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