Originally Posted by RaymondR
I used vinegar on my 3GM30 Yanmar
a number of times. Used a small bilge pump
in a bucket with a return hose from the exhaust
manifold to circulate it around for an hour or two, appeared to work well from the amount of gunk the vinegar picked up.
Interesting, I wonder if your thermostat had failed in an fully or partially open position.
The raw water
cooled GM series don't allow water
to circulate though block or head
with a closed (cold) thermostat. Well, they allow a very small amount but the bypass hole in the thermostat is only about 1 or 1.5 mm in diameter (1/16"). Nor does water
circulate though block or head
with the thermostat removed so the only way to flush these engines is to either:
1. Remove thermostat and close off the bypass hose (that's the small -short- hose).
2. Have the engine
agent at normal operating temperature (not easy to do)
3. Have a faulty thermostat that is permanently fully or at least half open.
I don't know but I think that Buhk (and perhaps Beta) engines are similar.
Yanmar GM Series (RWC) Thermostat Alert. - Cruisers & Sailing Forums
Marine Diesel Thermostats: NOT WHAT THEY SEEM - Cruisers & Sailing Forums