Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

All About Exhaust Systems

MrShift@EdmundsMrShift@Edmunds Posts: 43,626
This forum is specifically for exhaust system questions about any car. This includes catalytic converters, mufflers, tailpipes, hangers, bad smells, 02 sensors, smoke and possible drivability issues related to bad catalytics.

The forum is NOT for modifications (See our new "Speed Shop" Board!!)or for engine problems....just from the exhaust manifold on back, folks!


  • magillnmagilln Posts: 1
    It sounds like a chopper, has no acceleration, & is killing us with carbon monoxide in the car when our family is going somewhere. A leak in the exhaust near the engine would explain the carbon monoxide coming into the vehicle. The chopper sound, too, is under the front end. What I can't explain, is the lack of power & how that correlates with an exhaust system. Am I on the right track? Should I let a pro tackle this one? I can do a few things, maybe.
  • 1racefan1racefan Posts: 932
    Would a cracked exhaust manifold cause these symptoms?
  • Yes indeed, or a bad exhaust manifold gasket or bad exhaust manifold "doughnut" or connector (where the exhaust header connects to the exhaust system before the catalytic).
  • 1racefan1racefan Posts: 932
    In terms of his other question of how it would correlate to the lack of power - would that be because of the engine not getting the back pressure it needs from the exhaust system due to a leak?

    If it were my van, and it were otherwise mechanically sound, I would just spring for a whole new exhaust system (from manifold to tailpipe). Again, this is assuming the van is in otherwise good shape, and you think it can provide several more years of reliable service.
  • Yeah, lack of back pressure would be one explanation---that really depends on the engine, but sure...many a junior hot-rodder has put on too large a diameter exhaust system, only to find a noticeable DROP in horsepower.

    But the loss of power could also be co-incidental. You could have other engine driveability issues going on. So you can't really count on the fixed exhaust system curing the engine issues.
  • alcanalcan Posts: 2,550
    Mercury Villager and it's twin the Nissan Quest are chronic for broken exhaust manifold studs. The manifolds warp, which puts excessive strain on the studs and eventually snaps them. A major PITA to fix, requires manifold removal, drilling out the broken studs in the heads, and usually requires the manifolds to be replaced or planed flat again.
  • goducks1goducks1 Posts: 432
    He doesn't need a whole new exhaust system, just a new header. Why spend the extra money on parts that aren't broken?

    The symptoms (exhaust in the engine bay, loss of power, sounds like a chopper) are classic cracked header issues. I know because I just replaced the very badly cracked one on my Jeep's straight-six (these engines are notorious for this problem). I knew it had a tear near the collector but it had another worse one higher up:

    Look around the header as best you can with a flashlight, especially where it attaches to the engine block. This is not a cheap repair, though, but it's the labor and not the technical part that makes it so expensive, it's all grunt work. I was quoted $800-$1000, equally split between parts and labor, from the stealership and two different shops. I went aftermarket instead and picked up one from 1A Auto Parts for $160 or so, including a lifetime warranty on the part, and had a local boy-racer type install it (he did have ASE certification) in his garage for another $160 cash. Got it back yesterday and all problems are solved, I've got at least 20 more HP back and it's so very quiet now.
  • 1racefan1racefan Posts: 932
    I was just saying that if it were mine, I would replace the whole system. Again, that is based on a few assumptions - that the van is in otherwise good shape and that he has never had any exhaust work done previously - and that I was going to keep it for several more years. I just figure on an 11 year old vehicle, I would rather go ahead and replace the exhaust system and be done with it. Plus, I guess I sometimes take for granted the fact that there are several smaller repair shops in my area that are VERY reasonable, and do good work. But I agree with your comment about the dealerships - if it isn't warranty related, I try to stay away from those guys.
  • alcanalcan Posts: 2,550
    The manifolds usually don't crack on 3.0L Villagers, they warp and snap the studs which hold them onto the cylinder heads.
  • goducks1goducks1 Posts: 432
    ugh. Bad as a cracked manifold is, snapped studs are far worse. Serious, serious dough. I was praying all of mine would come out OK when the guy put in the new one but they were fine.
  • I drive a 1995 Subaru Impreza. I brought it for it's annual inspection and I was told that my emissions output reading was too high to pass inspection and that I most likely had a clogged up catalytic converter. I was given two options. The first being to replace the cat, or the second option to flush the entire exhaust system which, I was told, would help me with my cat problem and only run me $90. Would flushing the exhaust system only be a temporary solution (if any solution at all). Since I am female and I have limited knowledge about cars I wanted to make sure I wasn't being taken for a ride ;no pun intended.
  • Drive immediately to another repair shop. The whole thing sounds like nonsense. If you had a clogged catalytic, your car would barely run, if at all, and there is no such thing as "flushing" the exhaust system.
  • samos1samos1 Posts: 4
    I have a 2005 Hyundai Tucson that I purchased around christmas. I received bad gas about 2 weeks after. Car was taken to hyundai service center and repair work was completed. 7 months later my check engine lights came in and I returned to the same repair shop, they now tell me that the bad gas cause the converter's to go bad. This is after the repair and flush they completed back in January. Is the converters a part of the emission system? Is what they are telling possible?
  • Should be covered under warranty as part of the Federal emissions warranty. You may want to check with Hyundai.

    To answer your question, no I think their explanation is total BS even though the catalytic could of course be defective for some other reason. If your fuel delivery system is screwy, allowing the engine to inject a very rich mixture of fuel into the engine, that will eventually screw up a catalytic, yes, since it can't 'scrub' that much raw fuel. But that's not "bad gas", that's just too much gas.

    Last of all, if they haven't tested the catalytic, they don't know diddley yet.
  • samos1samos1 Posts: 4
    They stated they tested the converted and it was starting to clog, they check with Hyundai also and stated "they were told by Hyundai that this is not a warranty issue because of the bad gas i received from the gas station back in January 2005." I thought that since this part of the emission system it should be covered under warranty no matter what caused the problem.
  • sounds like nonsense to me, the whole thing start to finish. Either you aren't quite telling it right or they are making up some fairy tale because something isn't right here, and I don't mean that as a criticism. I realize that info gets jumbled when passed from party to party to party.
  • I have a 2004 Hyundai Sante Fe.... recently smogged vehicle(1st smog check) failed, the report says "Fuel Temperature Sensor A CIRC" my question is what does this mean ? Is this a warranty issue? Or should i attempt to have this problem fixed locally and how much can i expect to pay for a Temp Sensor repair?

    I might add I have noticed no other problems with my car and it only has 14K+ miles on it
  • burdawgburdawg Posts: 1,524
    Unless there's something really unusual going on, it has to be under warranty. The only exception I can think of is if someone has tampered with it.
  • The background on this is that I just got back from Central America and that the car had been sitting at my in-laws. I bought it used back in 2002 and it held up pretty well for the two years that I had it. Then the radiator busted in spring 2004. I tried to sell it before I left for Central America but I got busy with other stuff and it didn't get sold.

    Anyway, after I got back, I noticed right away that the mileage was poor and that the car lacked a lot of oomph (for lack of a better word). I had to get the car inspected for registration purposes, anyway, and so I brought it in. I was told then that my muffler had a leak (they showed me the hole, so this is legit). Because they had to order the part, I took my car out of the shop for a few days to pick up my mother at Dulles. On the way, after stopping for lunch, the car repeatedly stalled on me for a while, and even when it kept going, I still had the problems noted earlier.

    I brought in, and they said my catalytic converter is pretty much fried. I don't doubt this, as the symptoms I described earlier match what one would expect with a bad catalytic converter (at least based on the internet research that I've done in the last couple days).

    Anyway, to replace both the muffler, pipe, and cat, I've got an estimate of about $590. For a car that only books at $2200-2300 anyway, that seems like a pretty hefty repair bill (at least on my budget). In any case, I'd be willing to pay it if I knew that all would be kosher with the car again and that it wouldn't be right back in the shop a couple months from now.

    That said, everything I've read suggests that catalytic converters go bad because of other problems: timing, bad fuel mixtures, etc. I guess the good thing is that these problems sound easily remedied and hopefully wouldn't cost all that much. However, is it possible to figure out what the problem is before I authorize the replacement of the exhaust system? Is it possible that the cat died because of old age, much like the muffler seems to have rusted out? What do I need to think about before authorizing this repair?

    Thanks in advance to any with answers!
Sign In or Register to comment.