See full version: Where are the drain plugs on a 5. 0 MerCruiser
Re: Mercruiser 5.7 Engine Block Drain Location they are almost directly under the the manifold drains, about 6 inches down further, right where there oil pan meets the motor, basically in the middle of the motor from front to back.
Additionally, where are the drain plugs on a 4.3 Mercruiser?
Locate the two blue drain plugs attached to it, one on the starboard and one on the port side. If you face the motor, one will be on the lower-right side of the block about midway back. The other will be on the left side of the block behind the front motor mount. more
When I flushed the starboard one (and the block itself - under the
thermostat housing), water flowed freely out both block drains.
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At this point blast the fogging spray into the carb throat (remove
spark arrestor) until the engine dies. Some like to use Mystery Oil for
this. At this point the antifreeze has displaced any residual water in
the block and the fogging spray has protected the cylinders from
corrosion.
I think I might just buy a heater for the engine compartment to keep my
sanity.
here
Mine also has drain cocks on the sides of the block below the exhaust manifolds, right above the oil
pan.
--
John Herring more
On the port side of the engine it stopped dripping after quite a while. Ik poked a lot in that hole (sounds strange, I know) but no sand or other junk came out. Even on sb side not much junk came out. [links]
I will use some oil there. But keep in mind that these plugs are plastic. Shouldn't be very difficult to remove but you never know here
If you have any comments, please do. Otherwise I'll make some pictures on the way and place it here to help others. [links]
Ayuh. Ya gotta pull the big hose off the circulatin' water pump, rather than the t-stat housin'. [links]
Try to remove the left over thread in the next couple of weeks. Will try this with a left handed bolt remover (don't know the actual English word for it ) It's a pita to reach that spot. Ordered all new plugs (22-806608A 1) because the one broken looks dried out. here
Yesterdag, when we pulled the boat out of the water to put it in storage, I asked the club members to put it on a pedestal and leave it outside for 30 minutes so I could drain my block first before put my boat inside. Removed the hoses from the manifolds (no drain plugs there), removed the big hoses on the thermostat housing, removed the drain plug on port side of the engine (water was only dripping, even when poking) and then, tried to remove the drain plug on SB side but the SOAB broke and left me with the thread inside the block. Luckly the plug is hollow so the block drained for 10-15 minuten and should be empty.
If you have a 5.0 efi or MPI
These tend to have a single point drain method and are know to occasionally fail to empty all the water out after a few years of gunk and corrosion build up in the drain channels. You will need to fill or flush with antifreeze if you have this engine. here
Your best bet would probably be to keep the engine bay heated to say 10C which would stop the damp and mould but would also stop the water in the engine block from freezing..
With the 5.0 Merc, the filling will work;
If it's a carb with drain plugs;
Remove a plug each side (down below spark plug level and will either be a brass or blue plastic plug) watch water drain then poke a wire or small screw driver in there and make sure no junk is stopping water egress
Remove plugs on each exhaust manifold (usually at the back near cow horns) will be either a big brass plug (22mm spanner fits some) or blue plugs
Remove all hoses from thermostat on front of engine, then hold down as low as possible into bilge to drain.
If you have a hot water system off the engine, remove these two hoses and blow through one end to ensure water comes out other hose.
Now either replace all hoses and plugs or fill with antifreeze 50/50 mix (if you want specifics about this method let me know) then replace all hoses and plugs.
There is sometime a variant in the plugs, depending on the age. Some have all blue obvious butterfly plugs and some have a mix. The block drains (down side under spark plugs) are the most crucial.
Anti freeze (off the shelf stuff anyway) is poisonous so I don't think its a good idea to be pumping that through the engine block and into the river..
Because your boat is in the water, you will not be able to completely rid your engine systems of water, because some of the system will be beneath the water level of your boat. The intake hose from the leg to the thermostat (and perhaps power steering cooler) will still have water in them. Don't worry too much about this. The general idea is that the temperature of the water your boat is sitting in, will be the temperature of the water in this hose. This is because they are directly connected in a conductive sense.
Generally SW or flowing water doesn't freeze in these parts.
All the best
PS, the above has worked in the Scottish winters for the last 20 years of ownership, with regards to these specific engines.
Most recent engine I own is the 5.0 MPI.
Currently winterised as above and also filled with antifreeze (out water) more