Please note this thread has been inactive for 90 days. For the best results, please start a new thread.
Results 1 to 11 of 11
  1. #1
    Cadet
    Join Date
    Jun 2004
    Location
    Boca Raton, FL
    Posts
    11

    Default 1999 Mercruiser 3.0 Timing Cover Oil Leak

    I am a newbie to this board and feel fortunate its here as a great resource. Thanks in advance for your generocity and knowledge. I run in South Florida primarily salt water and am diligent about flushing with fresh water using the earmuffs. On my last trip out experienced a mild knocking noise. Came in and found quite a bit of oil in bilge...creamy tan floating on water. Using a flashlight found a gaping rust hole (large enough to fit a nickel through) in the timing gear cover completely exposing the gears. Im assuming the knocking noise that brought me in for the day might have been a low level condition. Been bummed for the weekend concerned about the extent of damage entolled. Whats caused this? Surprisingly, the oil remaining in the crankcase appeared normal in appearance. Did this breach wear from the inside out or the the reverse? The black enamel paint seemed flaking off. Is there an alternate material available for this cover? Thanks again.

  2. #2
    Petty Officer 2nd Class
    Join Date
    May 2004
    Posts
    160

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    That seems very early for a hole. It would have been fomr the outside I would say since the cover is generally covered in oil on the inside. That would prevent the rusting form inside. I have seen stainless steel covers before for boats but, I would think you might could find alluminium also. Stainless steel would be best if you run in salt water. You should check your timing chain and gear also if you havge to go that far. Consider a chainless unit if you can find the right one.

  3. #3
    Cadet
    Join Date
    Jun 2004
    Location
    Boca Raton, FL
    Posts
    11

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    Do you happen to know if replacing the cover will entail pulling the engine? Picked up a Clymer Manual today and mentions dropping the pan. Thanks Merc Blues!

  4. #4
    Petty Officer 2nd Class
    Join Date
    May 2004
    Posts
    160

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    You have to loosen the pan to get the cover back on if you don't want it to leak. How tight is it around the engine in your boat? Can you get to the pan bolts enough to loosen them without taking the motor out?

  5. #5
    Cadet
    Join Date
    Jun 2004
    Location
    Boca Raton, FL
    Posts
    11

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    I'll be looking into that when daybreaks in the morning. If the pan is loosened a bit for cover install, can the pan then just be retightened without cleaning the sealing surfaces, applying sealant, etc. Great if I don't have to yank the engine. Much obliged!

  6. #6
    Senior Chief Petty Officer
    Join Date
    Jun 2003
    Location
    Toronto Ontario Canada
    Posts
    665

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    Cj You can change the timing cover without removing the engine, but first you need to support the engine with a hoist or somthing, because the front engine mount will need to be removed, and be sure there is enough space to pull the harmonic balancer before you start. If you loosen the first two or three oil pan bolts from front to rear, the pan will give enough to get the cover out, At this time you may want to also replace the timing gears, this motor is direct geared timing (no chain) if they are knocking its time to replace, which will require removel of pushrod and lifters in order to remove camshaft to have new gear pressed on. When its time to install new timing cover, you can replace it with one for a SBC from your local auto parts store, don't forget to replace the front seal also. When ready to install the rubber front oil pan seal you'll need to trim the tabs at each end, and use a small bead of rtv at the corners where oil pan meets the block, and install cover, I did this with a 3.O merc I had in my last boat, took about 4 hours and never had any oil leaks.

  7. #7
    Cadet
    Join Date
    Jun 2004
    Location
    Boca Raton, FL
    Posts
    11

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    Could you explain a bit more the "rubber front oil pan seal". Isnt the seal just one large piece. Should I purchase a new one when Im just loosening the first two or three oil pan bolts remove and install the timing gear cover. The manual mentions just as you did, the need for the RTV sealant, but still unclear to me. Anyone with some input would be greatly appreciated. Thanks Northern Eclipse.

  8. #8
    Petty Officer 2nd Class
    Join Date
    May 2004
    Posts
    160

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    No the Seal on the cover is seperate and will come off when you remove the cover. There are tabs on the end of each one and as Northern Eclipse said you want to trim them so you can get the rubber back on place. use plenty of sealant at each corner.

  9. #9
    Senior Chief Petty Officer
    Join Date
    Jun 2003
    Location
    Toronto Ontario Canada
    Posts
    665

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    Thanks Mercury.

  10. #10
    Supreme Mariner
    Join Date
    Sep 2003
    Location
    Kitty Hawk NC
    Posts
    20,072

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    hello about the only way to properly do the job is to pull the engine. removing all the parts is easy. reinstalling the balancer is not. dont whale on it with a hammer. all hammer blows not only have the potential to destroy the balancer the force of the blow is transmitted directly to the crank thrust bearing surface. this surface is soft"babbit/tin" and can be severly damaged by hammering. you may wish to replace your circulating pump. they leak and cause the cover rust outs. you must remove the oil pan to properly orient the oil pan seal to the timing cover. its just a lot easier to remove the engine. good luck and keep posting
    no tech questions by PM, they wont get answered.
    you have to be trusted by the people that you lie to .

  11. #11
    Cadet
    Join Date
    Jun 2004
    Location
    Boca Raton, FL
    Posts
    11

    Default Re: 1999 Mercruiser 3.0 Timing Cover Oil Leak

    I appreciate all the great input. On the subject of reattaching the balancer, whats the preferred method. Can it be heated and dried ice wrapped on the shaft. Im not talking about heating it with a torch but what about an immersion heating pan?

Similar Threads

  1. 4.3 omc oil leak timing chain cover
    By phillyc1 in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 9
    Last Post: June 10th, 2008, 05:17 PM
  2. Timing cover leak ?
    By reags8 in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 2
    Last Post: May 28th, 2008, 08:29 AM
  3. Chevy(OMC) 350 Engine - Oil leak at timing cover
    By larry1167 in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 9
    Last Post: November 27th, 2007, 12:23 AM
  4. oil leak timing chain cover merc 3.0
    By mikeruta in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 8
    Last Post: March 11th, 2005, 04:23 PM
  5. Oil leak at timing chain cover bottom
    By KaGee in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 4
    Last Post: September 12th, 2004, 06:13 PM
  1. iboats Forum Directory - Over 100,000 forum posts organized by topic