No need to apologise for being a novice
. We all started there, the name of the game
is getting you to the pro stage with the least number of mistakes
or wasted $$$.
My take, and there will be other, equally or more valid than mine...
First, check the oil for signs of water. If there is water in the oil then all bets are off, either the engine was truly cooked, or you have disturbed the gasket
enough to make it unlikely to be able to reuse it.
Assuming no oil, carefully tighten up the head bolts using the correct sequence and torque for the engine. if you cannot find the exact specifications for that engine it is usually safe to find the specs and sequence for a similar HP engine with the same number of cylinders. Or, if all else fails, guess the sequence, use really small torque increases, and aim for a maximum torque around 35 ft-lbs to be safe.
Reassemble the rest of the engine cooling system and fill it with plain old tap water.
Check the oil again. Still no water? Good.
Check the raw water
supply line and seacock are good to go, leave the radiator/heat-exchanger cap off, and start the engine. Observe the radiator cap point with the engine idling, look for bubbles, usually a steady stream. The odd bubble may be nothing more than air pockets escaping from the block.
No air bubbles? Make sure the boat is secured, put the engine in gear
and BRIEFLY bring it up to about 50% throttle. Look for bubbles again. Still no bubbles, then you've probably dodged a bullet, the gasket
is ok, the head is still mostly straight. Shut the engine down before it or the exhaust
gets too hot, and proceed with the standard cooling system checks.
Simple cooling system test procedure for my boat would be:
level in engine ok? (in your case we are assuming plain water coolant at this point, no additives yet.)
2. Raw water
flow ok? Depends a bit on the engine when checking this bit. In my engine I know I should see regular pulses of water out the exhaust, each about a cup or two each, every two or three seconds. Other engines produce more or less, but the point is you should see water coming out the exhaust in most setups.
3. Let the engine start to warm and check that you can see the cooling water in the engine flowing through the heat exchanger
. Depending on the setup there should be a fair bit of swirling activity visible immediately below the filler cap. If there is then the cooling pump is ok.
If all these tests passed ok, then I would start looking at flushing
the cooling system with some kind of cleaning
flush, starting with plain old water, maybe a bit of vinegar, look on the web for ideas, before throwing in some horribly expensive concoction that may or may not work. After flushing
I would then drain some water from the engine and replace it with a good quality coolant additive and try again, 50% power in the pen and watch the temperature gauge(if fitted). If the temperature still gets too hot THEN I would look at pulling apart the heat exchanger and cleaning
it (though if you have it off the engine already I guess you will have done that before you put it back on.)
I still think the mechanic may be right with his original suggestion, but it seems you are not afraid of getting your hands dirty so it does make sense to double check all this for yourself. You may well have a perfectly fine engine under there and if you do get it going again you will know it well enough to monitor
FWIW I had my engine conk in the shipping
channel just last weekend. No wind
, a very slight current
, breakwater rocks either side of me. NOT a pleasant feeling. A quick check on the radio
told me the next shipping
movement was 15 minutes away, but that does not feel like a lot when you are faced with a 100 HP diesel
that turns over and will not fire while drifting slowly towards a rocky breakwater. These experiences remind us of just how important the engine can be. I know plenty of people sail without engines but the point is they KNOW they don't have an engine. It is finding out you suddenly don't have an engine that is the real problem.
Anyway, happy tinkering, let us know how you go.