Winterize engine

[Randygh]

After coming back from Anacortes last weekend, I flushed my engine with fresh water for 5 minutes or so. This week I changed the engine oil and filter, ran it for another 5 minutes in fresh water, then drained my exhaust manifolds and heat exchange unit. The water from the exchange unit was crystal clean, but the water from the manifolds was dirty with carbon. Does exhaust gas from the cylinders mix with the raw water that circulates through the exhause manifolds? I thought an exhaust manifold has a raw water jacket that doesn't mix with the exhaust? If there is no mixing of gas, where does the carbon come from that was in the water I drained from the manifold? My Osco manifolds are 3 yrs old and they drained dirty water the first time I winterized.

[pkrogh]

Randy, do you use Salt-A-Way or similar? If not then you will get that really
fine black rust that looks like soot.

I used to get it every time until I started using the SAW stuff. It's supposed
to form a rust resistant film on the iron and I guess it does!

Pete

[SomeSailor]

Does exhaust gas from the cylinders mix with the raw water that circulates through the exhause manifolds? I thought an exhaust manifold has a raw water jacket that doesn't mix with the exhaust?

Most exhaust manifolds are raw water cooled. This raw water is forced up and out the risers where it's carried through the risers. This depends on exhaust gas flow to carry all the soot out, but it's always bubbling and gurgling with the raw water. The soot is the runoff.

Imagine spraying a water hose up through your chimney at home. 99% of it will go up and out... the remainder would dry and carry away as steam... until you turned off both heat and water. The stuff coating the chimney walls would have to go somewhere.

I got in the habit of pulling the manifold drains after each flushing and experienced the same thing (black soot). I suspect idling while flushing adds to the quantity of soot too.

[Randygh]

I mixed 2 gallons of white vinegar with `20 gallons water when I flushed out the engine after coming home from Anacortes last week. Then 5 days after changing the oil I used water alone when I started the engine to circulate the fresh oil. Previously, I haven't used anything but fresh water to rinse out the cooling system and manifolds. I've always got the same sooty looking water when I drained the manifolds. Thanks Mike and Pete for the info.