Westerbeke 7.0 Water in oil

E

Eagleflyer

New Member
Apr 26, 2020
21
Long Beach, California
Boat Info
1996 Sea Ray 370 Sedan Bridge
Engines
Merc 7.4
I read some of the older posts about this but came away confused. There’s conflict in the discussion on whether 1990’s gas Westerbekes
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have an oil cooler. That aside, I’m not sure where to start.

If I pour coolant into the reservoir (metal tank attached to engine with radiator style cap) it drains down immediately. Checking the oil shows water in the oil but it’s also over full.

I set time aside over the next 2 days to dig in to the problem. Where is the most likely place to start inspecting? Head gasket, heat exchanger, etc?

Chris
 
Your coolant fill is the exhaust manifold. More than likely the manifold has failed, and is allowing coolant to drain into the exhaust (hence why it goes down quickly) as well as your cylinders, which explains water in your oil.
 
Manifold test fine. Blocked the 3 exhaust ports and applied vacuum....used smoke to look for leaks...noted zero draw.

Head gasket next?
 
Eagleflyer said:
Manifold test fine. Blocked the 3 exhaust ports and applied vacuum....used smoke to look for leaks...noted zero draw.

Head gasket next?
Click to expand...

So you removed the manifold and tested? Correct? Did you remove the cap on the top when you put it under vacuum?
 
Have you called westerbeke and spoke to a tech rep?

Other than that, a head gasket is a possibility.
 
Last edited:
Yep, starting to look like a head gasket problem, but it would still be best to talk to a tech rep before proceeding.

The cooler needs cleaning as well. Plus, you have lots of corrosion that needs to be cleaned up and treated.

Hopefully westerbeke has the parts (or you can get them locally). That's a Mitsubishi 3G81 6 valve engine from what I can see (or a variation of) so parts are still plentiful. Mitsubishi used these in Minicabs.
 
Followed up on the Westerbeke tech rep....Westerbeke doesn’t want anything to do with it....no help. No surprise.

I was leaning towards a head gasket issue as well.
Start that project tomorrow. Pics to follow....
 
CaptRonn said:
Yep, starting to look like a head gasket problem, but it would still be best to talk to a tech rep before proceeding.

The cooler needs cleaning as well. Plus, you have lots of corrosion that needs to be cleaned up and treated.

Hopefully westerbeke has the parts (or you can get them locally). That's a Mitsubishi 3G81 6 valve engine from what I can see (or a variation of) so parts are still plentiful. Mitsubishi used these in Minicabs.
Click to expand...

What’s the best method for cleaning the cooler?
 
Eagleflyer said:
Followed up on the Westerbeke tech rep....Westerbeke doesn’t want anything to do with it....no help. No surprise.

I was leaning towards a head gasket issue as well.
Start that project tomorrow. Pics to follow....
Click to expand...

Not surprised at westerbeke. o_O

There are companies out in California that rebuild those engines if you need any help, I'm sure they would talk to you, and offer parts (much cheaper than westerbeke).

I think you are on the right track with the head gasket.

Take the cooler off, rinse out several times. Then go to the grocery and get some CLR, and stand the cooler upright in a bucket or shop sink and pour in a diluted mixture of CLR and water, and let sit for a while. Rinse out several times afterwards.
 
Thank you...a few pics. The area I’m pointing has a lot of corrosion. Seems a lot of water has been present in this area. No real smoking gun other then that as far as I can tell.


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Looking closer cylinder on the right shows evidence of water. A gasket set for this engine is a pain to find locally. Found a company called king cobra part in KY that sells the set for $199.00. I have the Daihatsu engine.
 
I finished the project and so far all looks good. Generator runs well, holds a load and no water in the oil. I ended up replacing the head, exhaust and intake gaskets. The only thing I found that looked suspicious was the intake gasket. It had a defect that may have let water migrate. I’m glad I took the engine down, inspected the top end components and flushed the cooling system. If you have similar issues I would remove the exhaust and intakes manifolds first and inspect for issues. It’s a much smaller job and would be the first place to inspect. Hope this helps someone in the future. BTW- The King Cobra gasket set was $199 for almost all gaskets but the timing belt cover gasket was incorrect on my set. Closely inspect your gaskets for proper fit and usability.
 

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Eagleflyer said:
Looking closer cylinder on the right shows evidence of water. A gasket set for this engine is a pain to find locally. Found a company called king cobra part in KY that sells the set for $199.00. I have the Daihatsu engine.
Click to expand...

What model Daihatsu did you find it to be?
 
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