2007 Mercruiser 4.3 L MPI - Oil in bilge, not tons, but enough

[gt2003]

I pulled the drain plug last weekend after being on the lake for quite a while, sitting mostly, probably ran 20 minutes up lake and 20 minutes back but sat mostly in a cove with friends. I had my hand under the water that was coming out of the bilge and noticed there was an oily film on my hand. This is the first time I have noticed it and I've had the boat for a little over a year. It's not a crazy amount, the oil pressure stays fine and it's still within range on the dipstick. There is no obvious signs of where the oil might be coming from. I am NOT a gearhead but like to do all my own oil changes, winterization etc. The oil is not "chocolate milk" colored. I've felt around the valve covers and no greasy spots there. I've felt around as many hoses as I can, no obvious leaks there. Any ideas on what I might look at next to see if I can find where the oil is coming from? I'm planning to sell the boat early next year and buy a dedicated ski boat. I'd like to have the issue solved by then I just don't know where to look. Thanks

 

[achris]

http://forums.iboats.com/forum/engin...pdate?t=373060

and

http://forums.iboats.com/forum/engin...oil-leak-fixed

and

http://forums.iboats.com/forum/engi...818-a-second-4-3mpi-with-a-crack-timing-cover

and

http://forums.iboats.com/forum/engi...es-outdrives/561580-an-oil-free-bilge-finally

 

[Rick Stephens]

If I have water with some oil I have pretty much always had a bellows leak bringing in water mixed with grease from the ujoints. Might not be motor oil at all.

Rick

 

[Fun Times]

What color do you believe the oil to be that hasn't seemed to be mixed with water as of yet?

Next question might have to be 'how did a good amount of water get inside the bilge area? Do you suspect a possible water leak or more to be from normal usage such as swimming, live well tank, etc.?

Clean and dry the bilge area really well then run the engine on the garden hose to see if you have/see a water and/or oil leak....If not, plan on taking the boat a body of water with one helper and look for a water leak first while still on the trailer as you don't want the water sloshing around so much mixing with any possible oil. Then go for a few runs while stopping at times to check things out....< Or if possible, have the helper carefully hold the engine hatch open just enough to keep an eye out for early signs of leaks.

Good luck.

 

[gt2003]

We usually go out on the lake and will stay for 8-10 hours, most of it hanging out sitting in a cove w friends after we are done skiing. There is and has always been probably a quart or so of water that gathers in the bilge area, maybe a little more. I don't keep the boat in a slip and always trailer it so haven't thought too much of it. However, there has never been oil in the bilge water up until now. It's not tons of oil but enough that I noticed it. I will start by drying out the bilge really, really well. I had work done to replace the gimbal bearing last year and the mechanic said the bellows looked good at that time.

The oil in the bilge is the same color as the oil on the dipstick.

 

[gt2003]

I went tonight and dried out the bilge area. I used up all my towels so am washing them now so I can get the last little bit of water from the very stern tomorrow night. I'll run it on muffs Thursday evening and see if there are any water leaks from the engine and to see if any further oil is deposited into the bilge. I'll report back with what I find.

achris , is there somewhere on the engine I could "feel" to see if the oil is leaking from the area you talk about? Also, if it is what you are saying, will it continue to gradually leak into the bilge while just sitting?

That should give me enough info to keep the investigative process going. Thanks again gentlemen.

 

[bspeth]

use a shop vac to get the water out of your bilge

 

[Grub54891]

After cleaning the bilge, get some white oil sobs, lay the out in the bilge, take her out and run it like ya normally do. You will find a leak directly above where the leak is. It don't sound like much from here, Sometimes it's just the result from a small spillage when doing an oil change.

 

[gt2003]

Thanks Grub54891 , I'm going to dry out the rest tonight then run it on muffs tomorrow while doing what you suggested. Hopefully no oil directly from the engine. If no oil then time to recheck the bellows. Will update.

 

[desmopedro]

Do you have a tank for trim tabs or your trim rams in the engine compartment? Or....power steering? I guess what I am saying is maybe its NOT engine oil?

 

[gt2003]

Trim tabs are manual but I did check the power steering reservoir and hoses, no leaks. I did check the reservoir for the trim as well, no leaks. The bilge is clean and dry now. I'm going to run it on muffs this evening and see if anything reveals itself.

 

[gt2003]

I ran it on muffs for quite a while Thursday night. No water or oil in the bilge. I checked the bilge area thoroughly before putting it in the water Friday morning to see if anything dripped/leaked during the night, still no oil or water. After skiing a couple of sets I checked it and had the usual water in the bilge and a little oil around the outside edge of the water but nothing like it has been the last couple of times. We had the boat in the water about 8-9 hours total. I'm going to keep cleaning/drying the bilge and I expect everything will be cleaned out soon. I'm considering putting some fresh water in the bilge while its on the trailer and see if I can figure out where the water is getting in. The bellows looks good and soft/pliable from the parts I can see but it's got to be getting in somewhere. Any other ideas are appreciated. Thanks again

 

[Rick Stephens]

Water can come in from virtually any component on the transom. Shift bellow, seal on the water inlet pipe, gasket on the trim manifold, main gimbal housing seal, ujoint bellows, water passage o-ring, a crack in the transom. Best way to rule out some of them is to pull the leg and inspect the ujoint bellows to see if there is any water in it. This is a 15 minute task to take off, and a $10 gasket kit and another 15 minutes to put back on. Well worth the effort and not very difficult.

Rick

 

[gt2003]

Thanks Rick. I might take on that task. The boat shop pulled the lower unit last year to replace the gimbal bearing and said it was good but I've had about the same amount of water each trip this year as last. But hey, it would be a good learning experience!

 

[gt2003]

Well, it's only getting worse. I've got a friend who does a lot of mechanic work and actually pulled the motor out of his Tahoe a few years ago for a repair. Once season is completely over we are going to pull it an investigate. It's got one of the oil drain tubes so we thought about that, it sat with water in the bottom of the hull over one winter (Prior to when I bought it) so maybe it's an oil pan issue, he mentioned that maybe the rear seals have a tendency to go out on the 4.3's. There's just so many things it could be. Unfortunately the engine will likely have to come out to see what it is. I fully trust this guy and would rather assist and still pay him a reasonable amount than pay the shop $85/hour.

 

[Rick Stephens]

Nice part is, pulling an engine is really easy on a boat - literally took me half hour last week. I own a tractor that can reach in over the motor, so might be cheatin a bit. Hardest part of pulling a boat motor is finding something to lift high enough to clear the high sides of the boat.

Since you first started this thread you cleaned out the bilge and ran the boat some more with either towels or something similar to see where oil was coming from. Did you make any determination that it was engine oil yet and from the general area it came from? It is a lot easier to find a leak whilst running an engine than with it sitting static on a stand. If at all possible recommend you use mirrors, cameras on cell phones, anything to figure out the source before you tear things down.

Source of water leak is more straight forward. Generally, if you pull the outdrive, you can start inspecting and replacing questionable rubber stuff until you know you got the leak. Easier to start from a position of KNOWING you have 100% bellows by just getting a complete kit and replacing all of it.

Rick

 

[gt2003]

Previously I cleaned out the bilge completely and made sure it was completely dry. I did not put towels down but did run the engine on muffs for at least 10 minutes. No leaks at all. Then, before the next time out, I opened the engine compartment and there was a little oil in it. So, since I chose not to do it right the 1st time, I will clean and dry it again, run it on muffs a bit more and see if I can find where the leak is. We did discuss getting a mirror with extended handle to use while the motor is running to see if we can find it that way as well. I'll plan on replacing old rubber with all new rubber along the way.

 

[Bondo]

We did discuss getting a mirror with extended handle to use while the motor is running to see if we can find it that way as well.

Ayuh,.... A digital camera will put yer eyes where yer head won't fit,....

'n with a flash, ya don't really need a flashlight,....

Put it on a "Selfie Stick",....

 

[gt2003]

Well, I'm running out of time so I ran it to the mechanic on Saturday. The shop guys looked real quick, didn't see any accessories leaking and no obvious leaks. He did feel a little oil on the oil pan. He said MAYBE a rear main seal but they are going to investigate further and let me know. At least it will be fixed and fixed correctly so I can sell it quickly next year. I'll post back on what it ends up being.

 

[gt2003]

Boat shop just called. The oil drain hose was about a full turn loose. He was able to squeeze in there and tighten it up. He is pretty sure this has solved the problem. I'll be taking her out this weekend to make sure. I'd much rather spend the $70 than whatever it would have cost me to have a rear main seal fixed!