Hello all. I just finished an enjoyable, yet disappointing weekend on my boat getting a new (used) Westerbeke 7.7 KW diesel genset ready for action. I got her set in place and bolted down in the engine compartment, changed the oil/filters, inspected the raw water impeller, connected the wiring, changed the fuel filters, installed the exaust and muffler, and hooked up the battery. My last task before coming home was to refill the engine coolant resevoir. So, I pop off the filler cap and start dumping in the antifreeze. After about a quart into it, I've got antifreeze running out the side of the engine block into the drip pan (Uh - oh). My first assumption was that the cold Wisconsin winter cracked the engine block. Your thoughts?

Also, if this is the case, what can I expect to spend to get it repaired? The genset only has 500 hours of running time and appears to be in really good shape.

Thanx in advance for your advice.

Cap'n Jeff

Greetings,

I had a similar experience with a Kohler gas generator. The reason the side of the block cracked was because it had overheated (broken impellor and some jerk bypassed the temp switch). It was raw water cooled and leaked while it was running. Because it was not a “closed” cooling system there was very little water pressure in the cooling system. I had the thing brazed at a local machine shop, re-painted it and its been working fine ever since. If you are pouring anti freeze in it, then it is a closed system. I would pull it back out and take it someplace for a brazing (weld). I would then re-test it out of the boat to make sure that the cooling system holds pressure. Might also want to check or replace the head gasket. Usually these engines have freeze plugs that will burst to protect the engine block. When you changed the oil, did you find any water or anti freeze? Now me, being originally from Wisconsin, you should really consider moving down south here where these freezing problems don’t happen and you can enjoy that boat all year round! Go Packers hey!

Respectfully,
Botemon

Greetings again,

After doing some more thinking about this I think you better seek out a professional. Because you probably have a heat exchanger type cooling system that is pressurized, I am thinking that you may have the worst-case scenario. With a raw water cooling system my old Kohler was hardly even warm to the touch. A closed system (like a car) runs much hotter and you have heat expansion issues that any weld may not be effective. Let us know how it’s going!

Respectfully,
Botemon

Botemon,

Thanx for the quick reply. You're right, this generator has a heat exchange type of cooling system. Pressurized antifreeze/coolant circulates within the engine block. The coolant is then cooled by raw water in a heat exchange chamber. Hot raw water goes overboard with the engine exhaust.

Your comment about freeze plugs has me thinkin'. There was no antifreeze or water in the oil when I changed it. Pure "black gold". The anti freeze I poured into the filler neck ran out of the engine thru a 2 inch hole that had been intentionally cast into the side of the block. I'll bet it's an access hole to a freeze plug. If so, this is a simple fix (Whew!!!). I'll check it out this weekend on our 2004 maiden voyage on Pool 7 & 8.

Look for the freeze plug in the drip pan.

OH is right - look around - freeze plugs are not�put there to protect the engine - they are there to get the sand out of the block when it was cast in the sand casting process. If the plug(s) popped out there is a good chance you have a crack in the block - hope not- good luck

Well, I stopped by the local Westerbeke dealer and did some parts manual browsing with one of their technicians. The 2 inch diameter hole that I mentioned previously is where the "freeze plug" was supposed to go. Joe is correct in saying that "freeze plug" holes in the engine block are actually meant to provide a means to empty sand used during the _meta_l casting process. The W'beke parts manual calls them "expansion plugs". The technician seemed pretty confident that the plug would fail before the block would crack. He said that the plugs are designed to be a press fit, sealed with Permatex sealant. I ordered a new plug and will install it in a couple of weeks.

Please keep your fingers crossed for me, and thanx for all the good advice.

Great News! I installed a new expansion plug in the genset, filled her with coolant, and cranked her up. Purrs like a kitten, and no leaks!

Amazing that she sat on a trailer for 18 months (two winters), and popped right off.