Adding antifreeze

[affa]

Hi, I filled antifreeze through thermostat housing, but couldn’t add more than 13 liters, the manual says 20 liters for a Mercruiser 5L MPI, maybe the manifold doesn’t get filled that way? Can I start the engine and circulate the antifreeze in to the manifolds?
The drive is off
Regards
Affa

 

[DeepCMark58A]

Always circulate to fill all crevices for protection

 

[Bt Doctur]

How did you drain the system ? IF a single point system my guess the engine block did not drain completely. You can verify by unhooking the block drains and probing the fitting with a nail or screw..Almost every customer of mine with that system it
usually is the port side .

 

[DeepCMark58A]

My boat an inmar 351 has 2 block drains and 2 riser drains, you open that up let it drip close up the plugs and disconnect the intake hose suck 3 gallons of premix in and done. Then again I have a 1990 so it was simpler then.

 

[Chris1956]

You do not start the engine to circulate the antifreeze.

You pull all the plugs, which is 4 or 6 on a V engine. Probe/poke the drains and let all the water drain. Now add some A-F to the block, via the large hose on the waterpump. When you see it emerge from a drain, put in the plug and continue to add A-F until you see it emerge from the other block drain. Now put in the drain plug and fill the block with A-F.

Now add A-F to each manifold hose until you see it emerge from the drain. Put in the plug and fill it. Fill the manifold. Repeat with the other manifold.

If you have separate drains for the risers, follow that procedure for them as well.

Pull off the raw water hose and dump A-F down it until it comes out the water intake grate.

Strictly speaking, the block does not need to be completely full as you will not be running it over the off-season.

 

[affa]

How did you drain the system ? IF a single point system my guess the engine block did not drain completely. You can verify by unhooking the block drains and probing the fitting with a nail or screw..Almost every customer of mine with that system it
usually is the port side .

 

[affa]

Yes it’s one point drain, I unhooked on both sides, and it came fluid out, but it can maybe come from the hose? Not easy to see when unhooking it

 

[Bt Doctur]

you unhooked the block hoses but did you probe the brass quick connect in the block? Just seeing it dribble out instead of it pouring out ???

 

[affa]

you unhooked the block hoses but did you probe the brass quick connect in the block? Just seeing it dribble out instead of it pouring out ???

Thanks I’ll take a better look today

 

[affa]

It ran out ok when I unhooked the hoses on both sides,

 

[Lou C]

it is really surprising the extent that mercruiser went to just to avoid installing a half closed cooling system. When my brother had a late model merc, (2020 4.5 V6 in a Chapparal) I told him about this, as the boat ages and is used more sooner or later someone (not I that's for sure) is going to have to squeeze their body in some ridiculous un-natural position to clean out those drains. There's Merc with their ridiculous complex cooling system and Chapparal who provides NO engine access whatsoever for anything on the sides or back of the engine. All you could reach was the oil fill, oil filter, fuel filter and that quick drain. Anything else and the engine is coming out.
He listened to me and traded it on a similar boat with an outboard!
20+ years ago I redesigned the rear of my old boat so I could at least get at stuff after removing the seats (easy) and wood support panels (easy too). I can't respect the total disregard modern boat builders have for mechanics. I think they are finally coming around more and more sport boats have outboards now.
Old pic from 2007, still had the OMC batwings on it.

seats go in front of the wood bulkhead
I slightly smaller/lighter seats in it for the past 15 or so years, the original ones were too dang heavy to lift out...

 

[affa]

Yes true, I have a 2007 mod SeaRay 215 weekender, so it’s not to bad for the service.
I read something about removing the blue plug on the thermostat housing when draining it, I didn’t do that, can some water remain if I don’t open that plug?

 

[affa]

You do not start the engine to circulate the antifreeze.

You pull all the plugs, which is 4 or 6 on a V engine. Probe/poke the drains and let all the water drain. Now add some A-F to the block, via the large hose on the waterpump. When you see it emerge from a drain, put in the plug and continue to add A-F until you see it emerge from the other block drain. Now put in the drain plug and fill the block with A-F.

Now add A-F to each manifold hose until you see it emerge from the drain. Put in the plug and fill it. Fill the manifold. Repeat with the other manifold.

If you have separate drains for the risers, follow that procedure for them as well.

Pull off the raw water hose and dump A-F down it until it comes out the water intake grate.

Strictly speaking, the block does not need to be completely full as you will not be running it over the off-season.

 

[affa]

No that’s ok, but my concern is if it’s still som water left in the cooling system that can freeze