308 Engine: part ID/oil leak troubleshooting advice needed | FerrariChat

308 Engine: part ID/oil leak troubleshooting advice needed

Discussion in 'Technical Q&A' started by ArtH, Jul 10, 2005.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. ArtH

    ArtH Rookie

    Joined:
    May 16, 2005
    Messages:
    47
    Location:
    N. Virginia
    Hi,

    Got your detective skills sharpened up for sleuthing out an odd oil leak?

    I've spent some time tracing down a large oil leak on my 79 308. There's a little slow seepage at the head gaskets and one of the lower cam sprocket seals leaks a little. But these don't produce the amount of oil that soaks the underside and the pavement.

    Today I noticed most of the oil seems to come from the area of the red-arrowed location in the photo. This is on the forward side of the block below the starter and near the clutch linkage. The cylindrical protrusion is what I'm looking at, and there was wet oil at the seam/crack below it and at the hole in it's side.

    Get this: some previous owner patched over the whole thing including the hole on it's side with some glue/sealant which had come mostly unglued and was easy to chip off.

    It looks like it might be an oil overflow or vent. Is that a crack right below it or part of an engine seam? The seam was glued over as well.

    Any clues? Key question: If this is an overflow/vent, what could cause oil to drip out from there? If it's not a vent then what is the function of the hole in it? Either way, should it be plugged? Oil pressure is normal.

    I ran the engine for a few minutes, but the leak usually only drips when the engine is hot and I didn't see any oil coming from there in that short time, so I'll check it over the next few days.

    Maybe it's not the actual source of the oil, but it seemed suspiciously wet with oil as well as the area below, and the glue sure caught my eye!

    Any other ideas on this?

    Thank you very much for any help!

    Art
     
  2. ArtH

    ArtH Rookie

    Joined:
    May 16, 2005
    Messages:
    47
    Location:
    N. Virginia
    Last edited by a moderator: Sep 7, 2017
  3. Peter

    Peter F1 Veteran Owner

    Joined:
    Dec 21, 2000
    Messages:
    6,440
    Location:
    B.C., Canada
    If memory serves me right (from when I had my engine out of the car and had a better look), this protrusion, to me, looked like some kind-of boss used to hold the engine during the machining/manufacturing process.

    Why oil would leak out of here, I don't know. There are studs located near there that bolt the engine to the oil pan/tranny case, so that could be one of the reasons (over-tightened at one point, which cracked and now that oil splashes around behind there, it leaks out).

    Just my guess. To fix it properly, you may have to pull that engine out... Or just keep slapping on JB Weld...
     
  4. Verell

    Verell F1 Veteran Consultant Owner

    Joined:
    May 5, 2001
    Messages:
    7,022
    Location:
    Groton, MA
    Full Name:
    Verell Boaen
    I'd thoroughly clean & degrease the area (PITA to get to isn't it). Then put some UV dye in the engine oil, start up the engine & watch with an UV light to see where the glow first appeared.

    Oil can travel as an invisible film for a surprisingly long ways before you can see it. In this location, the oil could also be coming out of the block-bell housing spacer seam, or even from the front bank distributor, & just becoming visable down there. The UV dye is about the only way to see where the leak really is.
    You can get UV dye & LED pin kits from AutoZone for about $40.
     
  5. pma1010

    pma1010 F1 Rookie

    Joined:
    Jul 21, 2002
    Messages:
    2,559
    Location:
    Chicago
    Full Name:
    Philip
    Behind the bellhousing and flywheel is a big spacer. It takes a gasket. My guess is the gasket is starting to give out after 20 + years. (Mine did). You can see "your" boss in the second picture.

    BTW, you can see the rear main seal clearly in the first picture, another that tends to go with age (the one pictured is new).

    Second candidate is the gasket between the gearbox and the engine. Bigger job.

    Verell has given you good advice to pin point the issue first. As you can see, I did my seals and gaskets when we pulled the motor last winter.
    Philip
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
    Last edited by a moderator: Sep 7, 2017
  6. ArtH

    ArtH Rookie

    Joined:
    May 16, 2005
    Messages:
    47
    Location:
    N. Virginia
    Thanks everyone for your excellent help.

    A few weeks ago I cleaned up the joint between the block and oilpan/trans case right at the place I pointed out in the photo. The studs were tight, but I sent JB Weld to the rescue! My car is now housetrained! Hardly any drips now!

    There must be a little gap in the gasket allowing oil to splash out from the oilpan at that point, and JB Weld lives up to it's reputation. Maybe it'll last a year or ten!

    Thanks again!
    Art
     

Share This Page