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oil leak

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by scrappyk5, Sep 3, 2002.

  1. scrappyk5

    scrappyk5 1/2 ton status

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    i have an 84 k5 blazer with a 87 305 motor in it.
    i seem to have an oil leak that only leaks on the starter
    side. its not coming from above, it seems to be coming
    from the back of the oil pan. there is no oil leak on the
    oil filter side nor is it dripping from the torque converter
    cover.
    soooo, my question is , is it leaking from the pan gasket ?
    or is it leaking from the rear seal?.

    i would hate to go through the work of changing the rear
    seal if all it is is the oil pan gasket...
     
  2. 95 Silverado

    95 Silverado 1/2 ton status

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    if it were the rear seal it would probably be wet inside the bellhousing of the transmission, as it would be throwing it around from the spinning crankshaft. It may be one of those things you won't know till you tear it apart.
     
  3. ZZ4x4

    ZZ4x4 1/2 ton status

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    I had the same problem on my 350. It was a leak by the starter, and dripped down the starter mounting block. It was definitely the pan leaking. I lowered the pan a bit and sealed it with RTV. One interesting thing though... The reason for the leak was crankcase pressure. I replaced my PCV valves on the valve covers with simple breathers, and the leak stopped, even before I resealed the pan. JT
     
  4. scrappyk5

    scrappyk5 1/2 ton status

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    well , i checked the pvc and its good. it seems to be
    getting worse. it is all over the bottom of the starter,
    the oil pan. i looked up inbetween the oil pan and the
    converter cover and it is all wet. i still not positive
    its the seal. for some reason i have a gut feeling the
    oil pan gasket is leaking right at the back.
    if it was the rear seal, would it be all over the starter?
     
  5. Calclips

    Calclips 1/2 ton status

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    Pull the inspection cover off of the torque converter and see if there is a lot of oil in there that has been thrown around. It seems that if oil was coming out of the rear main it'd be getting thrown all over by the TC/Flexplate/crank
     
  6. ZZ4x4

    ZZ4x4 1/2 ton status

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    If your rear seal is leaking, most likely you would see the oil coming from the hole at the bottom of the trans sheild. I don't think it would run down the starter because of the shape of the sheild which tucks under the lip of the pan. Of course who knows what the oil will do in the wind under the truck. Just a note ...my PCV valves checked OK also but I guess the 1 psi activation pressure was enough to find a weak spot in the pan seal. In any case, it would be easier to reseal the pan than replace the rear main seal, so you may want to give it a shot. It is still a major pain with the cross member being so close to the pan, but it can be done. You don't need to pull the pan off. Just drop it down an inch and carefully squeeze some grey or red rtv sealer made for hot oil resistance into the area. The most common area for a leak is the corner. I pulled the starter when I did mine so I could get in a little easier. Good luck!
    JT
     
  7. zakk

    zakk 1/2 ton status

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    this will sound dumb, but it was my problem.

    We put a brand new 300hp GM crate motor in and the thing leaked immeditly.

    nothing on the pan, seals were ok, but it was all over the starter.

    What happened was the block was a universal. it had dipstick provisions on both sides, and the dowl had fallen out of the side we didn't use /forums/images/icons/smirk.gif typical of us. /forums/images/icons/laugh.gif

    just passing along some more useless information /forums/images/icons/grin.gif
     
  8. shane74

    shane74 1/2 ton status

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    I took my trans sheild off because of the exact same problem. Mine was a bent pan and a bad gasket. I have a 2 piece rear main, so I replaced it at the same time. You won't be so fortunate. I also spent the money for a new pan and a 1 piece fel-pro gasket (about $35 shipped to my door). Works like a charm! and I have slightly higher pressure too. It runs about 45 psi when warmed up and cruising down the freeway and drops to about 30 psi at idle. When it's cold, it just about pegs the gauge! LOL!! /forums/images/icons/shocked.gif
     
  9. scrappyk5

    scrappyk5 1/2 ton status

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    i will pull the converter cover off today and see.
    thanks guys. if there is oil all up in there, then i will
    know for sure which.
    oh, my oil pressure at warm-up is about 50psi , and at idle
    its about 25-30 psi.
    i did noticed that when i had just recently changed the oil,
    i put about a half quart too much in. its about a 1/4"
    over the full mark on the dipstick.

    on other question , can i slide the tranny and the t-case back at the same time, or do i need to completely remove
    the t-case from the tranny?
     
  10. shane74

    shane74 1/2 ton status

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    You should be able to slide the t-case and tranny back at the same time if you need to replace your rear main. I'm not sure if it would be easier to yank the engine or not. If you can get ahold of a jack that will mount to both the tranny and t-case then you are set. If not, it could get aggravating real quick. /forums/images/icons/crazy.gif
     

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