raw water in my oil...

clownfish · Post by **clownfish** » Sep 10th, '09, 09:32

Yesterday, I checked my dip stick and found that the oil was white. I ran the engine a few days earlier with no problems. Before I ran the engine last time, I tightened up all of my hose clamps and believe that I may have left my Vetus muffler in too high of a position. Would this cause backflow into the engine? I cut the hose and lowered the muffler as low as I could behind the engine. The discharge hose loops up above the water line and out the transom. Is this the proper set up? I changed the oil about four times and it runs fine. When I left the boat yesterday, no additional water had entered the oil.

Has this ever happened to anyone?

I have a CD 28 with the original MD2B.

Any advice or comments are appreciated.

Thanks in advance!

Dane

Steve Laume · Post by **Steve Laume** » Sep 10th, '09, 09:56

Do you have a vented loop in the raw water discharge?

This can also occur if you crank the engine too long without starting, while the seacock is opened.

Glad you found this before you encountered the major problems that could have resulted if left undiscovered, Steve.

clownfish · Post by **clownfish** » Sep 10th, '09, 10:02

No, I do not have a vented loop. I should add one?

Ben Thomas · Post by **Ben Thomas** » Sep 10th, '09, 10:26

Vented loop may solve your problem. here is a link showing common exhaust systems.
http://betamarinenc.com/exhaust%20systems08oct.pdf

Good luck!

clownfish · Post by **clownfish** » Sep 10th, '09, 10:38

Thanks Ben, that is what I was looking for. I just hope that backflow is/was the problem...

Maine Sail · Post by **Maine Sail** » Sep 10th, '09, 11:34

The siphon break should be located at a high point before the raw water is injected into the exhaust elbow. This prevents siphoning, and the filling of the exhaust & muffler when you turn off the engine.

The siphon break does not go in the large discharge hose that goes to the transom but rather in the small hose injecting raw water into the exhaust elbow..

You may already have one but it could be plugged or dirty and no longer breaking a siphon event..

Bob B · Post by **Bob B** » Sep 10th, '09, 14:26

We had the same problem with a 1GM but it had corrosion that had worked its way through the cylinder head so that there was water from the exhaust working its way back into the oil. We realized this after we blew a cylinder head gasket. Thought the oil was due to this but on removing the head found pits all the way through to the cooling water areas of the head. replaced this with a Yanmar manual and was fairly pleased with the outcome.

sgbernd · Post by **sgbernd** » Sep 10th, '09, 15:16

You might try leaving the raw water seacock closed when the boat is not in use. If the water is seeping past the water pump, filling the muffler and moving back to the engine, closing the seacock will stop it. As a rule, it is a good idea to leave the seacock closed when the boat is not going to be used for a few days as good practice. If water still gets into the oil, with the seacock closed, you may have an internal fault as previously described.

My original MD7B lacks a vented loop but has never had any trouble either.

BTW, some of the early Volvo water pumps were mounted on the block with the pump shaft driven thru a seal. If the seal failed, water could make its way thru the pump into the crank case. Later pumps had a "weep" hole along the shaft that was supposed to indicate the seal had failed by you noticing the drip and rust stains. However, if the weep hole became clogged with rust, the result could be the same. You might inspect the pump and see the weep hole is clear and not leaking.

-steve

clownfish · Post by **clownfish** » Sep 10th, '09, 21:50

When I bought the boat early this year, it overheated to the point of blowing the head gaskets on the way to my marina. The temp gauge didn't work. We replaced the head gaskets, exhaust manifold gasket etc. The cylinders looked ok. I haven't had any problems until now. Unfortunately, I'm 20 miles from an inlet and use the engine often. I did notice corrosion on the water pump that is getting worse. When I left the boat yesterday, the oil looked fine and when I checked it today, it was higher on the dipstick and milky. Needless to say, I'm bummed. I'll change out the oil a few more times, take a good look at my water pump and keep my seacock closed. I still feel like the muffler setup is wrong, I'll work on that too.

I REALLY appreciate all of your help!

Sea Hunt · Post by **Sea Hunt** » Sep 10th, '09, 22:07

A good friend taught me a safety idea about closing raw water intake on diesels even though I do not yet own a CD with a diesel.

I was taught to always attach the engine key to the raw water seacock lever when closing the raw water seacock. In this way you insure that you never start the engine with the intake valve closed. I have no practical experience with this procedure but it seems to make sense.

Ron M. · Post by **Ron M.** » Sep 11th, '09, 07:21

What type of Vetus muffler do you have ? is it the canister type ? Most often they are mounted as close to the exhaust/mixing elbow as possible and low - next to or behind the engine.
As mentioned a vented loop on the intake side is a real good practice and easy to install. Sounds as though your exhaust is ok......running up above the waterline and down and out the transom.
Practical insurance is NOT to leave any interior seacocks open when off the vessel.........working them keeps them from getting stuck.
________
Vapormatic

Steve Laume · Post by **Steve Laume** » Sep 11th, '09, 10:30

Sea Hunt wrote: I was taught to always attach the engine key to the raw water seacock lever when closing the raw water seacock. In this way you insure that you never start the engine with the intake valve closed.

Because I could be a total space shot at times this has been my practice on Raven.

I also have a lose wire tie on the hose that can be slid down over the lever so that the lever cannot work it's way into the closed position.

Clownfish, I am really sorry to hear this was not a one time problem. It seems like you have to figure out what the problem is without trying to change all kinds of things.

The positive side of this, is that it has happened at the end of the season, Steve.

clownfish · Post by **clownfish** » Sep 11th, '09, 19:50

SeaHunt, that is a great idea. I always leave it open, will put the key on the seacock tomorrow. The seacocks for my cockpit drains are frozen in the open position

Ron, I suppose it is a cannister type. It is grey and somewhat rectangular with the inlet on the bottom of one side and the outlet on the top of the other side.

Steve, down here in Fl, sailing season is just about to kick in... August and most of September are brutal. October is the finest month.

I'm still keeping the faith, it must be the muffler or the water pump!!!

Otherwise, I'm in for a learning experience.

You guys are great, I'll keep you posted.

clownfish · Post by **clownfish** » Sep 14th, '09, 21:49

Since I changed the oil again and closed the seacock, no water has entered the engine. Started up like a champ. This is good! Haven't had time to rebuild the water pump yet, but plan to this week.

clownfish · Post by **clownfish** » Sep 16th, '09, 16:31

Steve,

It was the water pump, a $50 dollar fix.

Thanks a bunch!

The Cape Dory Board

raw water in my oil...

raw water in my oil...

exhaust

The siphon break

Corrosion in cylinder head

Water in oil - diagnostic ideas