1999 Mercruiser 5.0 Thunderbolt

[mirekjanowiak@charter.net]

After finding some oil in the bilge, I went to the dipstick to check the level, and it was dry. So I filled it to the proper level, and in three hours I have a leak of about 3 quarts. So I stuck my head into the doghouse, and saw a leak on the left side. I could not see it right away, so I from the right side got a mirror on a stick, and went under the motor to the other side, and saw the leak. ITS THE DRAIN PLUG, on the oil pan, I am pretty positive. Well now I am clueless. I have no way to get access to that left side since everything is very, very tight. It looks like I need to pull the motor out, at least, lift it to get at the oil pan. Does anyone know if I could take apart anything on the left side to get me down there? The left side front has the water seperator, then starter, then above all that I have the exhaust manifold, or exchanger. Would it be easier for me to take some things off that left side, or just pull the motor out? If I need to pull it, how do I go about it? Any ideas greatly appreciated.....Mirek

 

[Don S]

Re: 1999 Mercruiser 5.0 Thunderbolt

Since about every boat is different, it's impossible to say what you need to do. No one here can see what access you have.
But let me say this. I have boats that come in that have to have the engine pulled to replace impellers, spark plugs (even plug wires), starters, and about anything else you could imagine. Let alone the drain plug on the very bottom of the pan.

 

[Bondo]

Re: 1999 Mercruiser 5.0 Thunderbolt

Ayuh,........

And, I think you're explaining Where things are as you Look Back at your motor,.....
Rather than how they sit in the boat,......
'Cause the Starter on a Chevy,.... Is on the Starboard Side........
Not the Left side of the motor........

There's Always the Chance that you could reach the oil Pan Plug by removing the Manifold,.......
That's a Big Chunk out of your Way.......
But, Like Don says,....... Every boat is Different........

 

[mirekjanowiak@charter.net]

Re: 1999 Mercruiser 5.0 Thunderbolt

Sorry, I have a Alpha One stern drive, and no room to get to the starter, or even to the oil pan. I used a mirror from the right side of the motor, port of boat to see under the motor to the left side, starboard of boat, and saw a drip, drip, drip somewhere around the oil plug, I think. I need help to maybe take a few things apart, and get to the bottom on this 5.0 Mercruiser. Maybe then I will see the leak better. Or maybe just leaving everything together, and just lifting, or pulling the motor. My friend has a lift to raise it, but I need some instrustions on how to properly hoist the motor out in tact, as much as possible. Any ideas? Has anyone pulled out a Mercruiser V8?

 

[Don S]

Re: 1999 Mercruiser 5.0 Thunderbolt

Has anyone pulled out a Mercruiser V8?

Only 2 or 3 per month for the past 15 years.

Sounds like you are really new to boat mechanics in general. Before you start pulling things apart, get an OEM service manual
You need Merc manual #24 PN 90-861327--1 You DO NOT need the supplement, it's for the 6.2L engine only.

 

[mirekjanowiak@charter.net]

Re: 1999 Mercruiser 5.0 Thunderbolt

Well I took it in for a quick look over, and found out that they are saying its a possible rear main leak, R & R engine, their words... Am I looking a huge bill, and maybe a swap out for a rebuild motor?

 

[Don S]

Re: 1999 Mercruiser 5.0 Thunderbolt

They have the boat and can see what it's going to take to pull the engine, and they are the ones doing the work. Have them give you an estimate.
Cause I sure can't tell from your picture what it's going to take to pull the engine. But if all that is leaking is the rear seal, all it will probably take is a new rear seal and a pan gasket and an hour or so of labor to change the seal (Once the engine is out). Absolutely no reason for a rebuilt engine because of a leaky seal.

 

[paulrfrancisco]

Re: 1999 Mercruiser 5.0 Thunderbolt

Rear main seal or oil plug... ? Did you say the oil pan was empty and you refilled and after some time it was down 3 more quarts? In this time was the motor running or off... (I hope it wasn't running empty for your sake...) Oil cannot leak out the rear seal if its not running if I'm not mistaken... so I'd err to the oil plug, but...I'd be surprised if it the actual plug... sometme the pans rot out near it though....

 

[bruceb58]

Re: 1999 Mercruiser 5.0 Thunderbolt

Could also be a rusty oil pan.

 

[mirekjanowiak@charter.net]

Re: 1999 Mercruiser 5.0 Thunderbolt

Well just took the exhaust manifolds, elbows, starter, off and now found the issue, a oil pan hole. I need to replace the oil pan, with gasket....
Do I need to take the alpha one off the transom to pull the motor up about two feet? If so some pointers would be great.
Also I see two motor mount screws in front, what do I need to lossen in the back of engine to lift the engine up a bit? Instrustions please....

 

[Reel Poor]

Re: 1999 Mercruiser 5.0 Thunderbolt

Sounds like you are really new to boat mechanics in general. Before you start pulling things apart, get an OEM service manual
You need Merc manual #24 PN 90-861327--1 You DO NOT need the supplement, it's for the 6.2L engine only.

If your gong to do this job yourself you really need to get the manual ASAP.

 

[mirekjanowiak@charter.net]

Re: 1999 Mercruiser 5.0 Thunderbolt

I have one, but really looking for some expierence from someone who has done this. Other than the two motor mounts bolts, what else is there holding the engine to the transom assembly?
Do I need to pull the sterndrive off?
Will it just come up and towards the bow? I just need about two feet to install the oilpan.
Any suggestions greatly appreciated....

 

[Don S]

Re: 1999 Mercruiser 5.0 Thunderbolt

Yes, you have to pull the outdrive, not only will it make it easier on the coupler when removing, but you have to realign the engine once it's reinstalled.

Since you have the manual, Be sure to read and understand pages 2A-3 and 2A-5 of the service manual.