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308 Exhaust Leak - is this common?

Discussion in 'Technical Q&A' started by GearHead, Jan 4, 2004.

  1. GearHead

    GearHead Karting

    Jan 3, 2004
    76
    A 308 that I looked at (less than 20K miles on it) seemed to have an exhaust leak on the rearward cylinder bank. Like a cracked manifold or something - the sound was coming from around that area.

    Common problem? Expensive problem?
     
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  3. Peter

    Peter F1 Veteran
    Rossa Subscribed Owner

    Dec 21, 2000
    6,389
    B.C., Canada
    Cracked manifolds happen occasionally. Poorly made to begin with.

    Expensive?

    • Yes, to replace with new. Less-so if used.
    • Not really if repaired by a welding or even a better-equiped muffler shop (headers are stainless).

    I can't remember, but I think either Tubi or Stebro (or maybe both) make stainless aftermarket replacements.
     
  4. Peter

    Peter F1 Veteran
    Rossa Subscribed Owner

    Dec 21, 2000
    6,389
    B.C., Canada
    ...Or it could be just a bad doughnut gasket at the header/muffler flange...
     
  5. Newman

    Newman F1 World Champ
    Professional Ferrari Technician Consultant Owner

    Dec 26, 2001
    13,592
    Canada
    Full Name:
    Newman
    One of my primary pipes on the rear head had a cracked weld when I bought the car. A mig welder fixed that 2 years and 15K ago, still no leaks.
     
  6. BigTex

    BigTex Seven Time F1 World Champ
    Rossa Subscribed Owner

    Dec 6, 2002
    73,206
    Houston, Texas
    Full Name:
    Bubba
    BOTH my headers failed due to distributer advance problems. Blew into lots o' pieces!

    Replacement cost was all over the map. $200 - $750.

    I've seen an add recently for custom replacements from a vendor in the UK, looks like nice work.
     
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  8. Wayne 962

    Wayne 962 Formula Junior

    Nov 27, 2003
    434
    What do you guys think, would an exhaust leak cause extreme backfiring when:

    - Coasting down from speed with your foot off of the throttle, and the transmission/clutch engaged
    - Backfiring (every time) when you turn off the car
    - Flub-flub-flub noises coming from the exhaust (burning exhaust gases)

    I definitely have an exhaust leak, but I'm not sure if fixing it will completely eliminate the problem?

    -Wayne
     
  9. peterp

    peterp F1 Veteran

    Aug 31, 2002
    6,006
    NJ
    Full Name:
    Peter
    I had noisy exhaust with some muffled backfiring on decceleration and the problem turned out to be 2 bad hoses in the exhaust. I don't know the name of the hose (it was fixed by a shop), but I think they are used to recirculate exhaust gasses. It was an amazing difference in quieting the car. This was for a 3.2, I'm not positive that the 308 has the same setup.
     
  10. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,220
    TN
    What are some of the signs of an exhaust leak or cracked manifold on a 308?
     
  11. Sean F.

    Sean F. F1 Rookie

    Feb 4, 2003
    3,003
    Kansas
    Full Name:
    Sean F
    Are the air pumps hooked up on that car? If not, the leak could be blowbye at the air injectors in the exhaust. If not properly plugged, they will blow bye and cause a chirping noise.
     
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  13. yank05

    yank05 Formula Junior

    Nov 8, 2003
    260
    New England
    Full Name:
    Anthony
    Hi,

    I had the same symptom on my 308 . The analyzer tubes in the front manifold were rusted and leaking - made the familiar exhaust leak "ticking" noise. You can plug the holes with the proper brass plugs - not sure of the size (Ferrari UK has them I believe).

    Thanks,

    Anthony
     
  14. FerrariFrank1

    FerrariFrank1 F1 Rookie

    Aug 15, 2003
    3,887
    Chicago-Phoenix-L.A.
    Full Name:
    Frank
    My '81 308,makes a kind of "Whistling" noise when I accelerate. Reminisce of an old VW Beetle. Is that the "Blow By" problem ? The car only has 18K miles.
     
  15. philvecc

    philvecc Formula Junior
    Silver Subscribed

    Nov 3, 2003
    743
    Longmeadow, MA
    Full Name:
    Philip Vecchiarelli
    Had the same problem with my '85 308. It split right at the header flange/pipe weld on the right end. Twice, as a matter of fact. The first time we welded it back in place, but it was evident that it was under stress since it split again. So we milled the flange face flat, and took a piece of stainless tube about 1/2" wide same diameter os the pipe, split it, wrapped it around the junction leaving the gap underneath open, then welded it up and haven't had a problem in two years.
    I was quoted $1,800 for a new one.
    Good luck!
     
  16. pnorman

    pnorman Rookie

    Dec 30, 2003
    47
    The whistling is from the exhaust tips having lost their fiberglass packing not an exhaust leak...Patrick
     
  17. 1975gt4don

    1975gt4don Formula Junior

    Nov 5, 2003
    662
    Peoples Rep of CA
    Full Name:
    Smog Exempt
    I believe I have the same problem on the rear bank also, I can smell strong exhaust fumes when I lift up the engine hood with the engine running. I am wondering how you can tell if this is leaking with the heat shrouding material all around the header? Even to repair the manifold, it looks to me like the heat shielding material needs to be removed first.
     
  18. flashman

    flashman Formula Junior
    Silver Subscribed

    Jan 5, 2004
    479
    Star Valley, Arizona
    Full Name:
    William Rappaport
    Patrick,
    Is there a way to fix this problem without completly replacing the exhaust tips? I also am having the same problem as red 81 308 on my 81 308 GTSi. Is this a problem common to our model?
    Thank's
    WilliamR
     
  19. Wayne 962

    Wayne 962 Formula Junior

    Nov 27, 2003
    434
    My floorjack is at the shop right now - when I bring it home, I will take some photos. Seems like these exhaust leaks appear to be a common problem on these cars, yet there didn't seem to be much in the archives about them.

    -Wayne
     
  20. Dr.T348

    Dr.T348 Formula 3

    Jan 8, 2004
    1,599
    Chicago NW Burbs
    Full Name:
    Richard T.
    You might want to check the emmissions hoses. There are " check valves " on cars with air pumps. I had a bad check valve and replaced and leak was resolved.
     
  21. FerrariFrank1

    FerrariFrank1 F1 Rookie

    Aug 15, 2003
    3,887
    Chicago-Phoenix-L.A.
    Full Name:
    Frank


    Thanks Much! I appreciate that! Guess I may be installing a Tubi sooner than when my 30K is due.:) Thanks again!
     
  22. Wayne 962

    Wayne 962 Formula Junior

    Nov 27, 2003
    434
    Where are these located, and how do you check them.

    (I'm up to my elbows in four cars that are having problems right now - Pathfinder (smog), 2 BMWs (smog) and the Ferrari.)...

    -Wayne
     
  23. Lawrence Coppari

    Lawrence Coppari Formula 3

    Apr 29, 2002
    1,914
    Kingsport, TN
    Full Name:
    Lawrence A. Coppari
    My 328 developed an exhaust leak at a check valve that lets in outside air to heat the cats faster. There is one for each bank on a 328. When they corrode out, it sounds like an exhaust leak. But I don't know if a 308 has them. They are GM parts.
     
  24. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    19,360
    Texas
    Full Name:
    Steve Magnusson
    Wayne -- With regard to: "Where are these located, and how do you check them.", your F OM should have a decent illustration showing their location(s).

    With regard to checking their function, the first thing to do is make sure they haven't just generally disintegrated ;), but, if you remove the flexible air supply line from them, no exhaust should come out backward with the engine running.
     
  25. Wayne 962

    Wayne 962 Formula Junior

    Nov 27, 2003
    434
    When I get done working on my truck, I will jack up the 308 and take a long, hard look at what's in there (I'll take pics too). It sounds like there may be numerous places for an exhaust leak to occur...

    -Wayne
     
  26. Glassman

    Glassman F1 World Champ
    Silver Subscribed

    Apr 23, 2002
    13,135
    As posted above, chech the air pump maifold rail first. The one on my car at the back of the engine had a hole in it. The front for some reason is perfect. These are very tin tubing and with the air pump disconnected the corrosive gasses come thru it and eat it all to hell.
     
  27. flashman

    flashman Formula Junior
    Silver Subscribed

    Jan 5, 2004
    479
    Star Valley, Arizona
    Full Name:
    William Rappaport
    I just went through my exhaust system and found out what was making the noise. I have a small (1/2") crack in the rear exhaust collector. Can this be patched or does it have to come off the car to be welded?
     
  28. SR Ferrari

    SR Ferrari Rookie

    Dec 1, 2003
    48
    Gear head 90% of exhaust leaks are at the CO correction tubes where They go into the manifold they just rot off take a close look if you can to see the condition of the front tubes if the fronts look bad then restasure the rear ones are the same/
    look for missing manifold nuts also.
    Perry Solamens 85 308QV has be the best car at Montery for the last couple of years I simply had the oportunity to have the manifolds out of the car and we removed the tubes and closed the ports with a clean healiarc welds as per Perrys request.

    This may not be the answer for you but if this is the case the manifolds need to be out of the car either way.
    Kind Regards
    Wayne Hynes.
     

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