Flushing OAT coolant out of engine

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Dull Spark

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I am about to change the coolant in my Beta 30. The current manual recommends mono ethylene glycol, extended life, but the engine has OAT in it.

Any suggestions for flushing the old stuff out and being sure it's all gone? I have a calorifier, so expect to do a couple of flushes to get enough of the old stuff out.

Is it worth putting some cleaning compound in for a few hours to clean up the cooling passages?

Many thanks.
 
Just use fresh water and flush it plenty. If you can get a hose and flush through with low pressure will speed the process without having to run the engine.
 
black mercury said:
Just use fresh water and flush it plenty. If you can get a hose and flush through with low pressure will speed the process without having to run the engine.
Click to expand...

That will certainly help ... but the problem is that unless you run the engine up to temperature, or remove the thermostat, the chances are that there will be a body of old antifreeze that won't be shifted.

I decided to flush through and run to temp until all the old antifreeze was out and the drained coolant was running clear. It took me 4 or 5 complete flushes up to temp before I was satisfied so it's not a quick process.

If the engine has always been run with antifreeze there's probably no point running any cleaner through as any crud build up will be minimal.

Richard
 
Thanks. I'll try to avoid removing the thermostat - just another gasket to replace and check up on.

Looks like it just needs a comprehensive flush-out, so I need to get as much coolant out each time as I can.

Will it matter if some OAT is left to mix with the new coolant?

Many thanks.
 
Dull Spark said:
I am about to change the coolant in my Beta 30. The current manual recommends mono ethylene glycol, extended life, but the engine has OAT in it.

Any suggestions for flushing the old stuff out and being sure it's all gone? I have a calorifier, so expect to do a couple of flushes to get enough of the old stuff out.

Is it worth putting some cleaning compound in for a few hours to clean up the cooling passages?

Many thanks.
Click to expand...

You understand, of course, that extended life coolants are OAT. You really don't need to flush at all, only drain and refill. Tell us which two coolants, and we can discuss chemical compatibility.

No your do NOT want to add a cleaner. Anyone in the coolant formulation business shudders at those. (I was in the formulation business for several decades and have several patents.)

And there really is not such thing as "extended life" in marine applications. The change interval is always shortened to 2-3 years to allow for the risk of seawater leakage into the cooling system. Just 1 part per thousand is enough to ruin the coolant. However, the chemistry of extended life coolants is what they want for other reasons. That's a long story, and not one you can unpack in a forum.
 
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Dull Spark said:
Thanks. I'll try to avoid removing the thermostat - just another gasket to replace and check up on.

Looks like it just needs a comprehensive flush-out, so I need to get as much coolant out each time as I can.

Will it matter if some OAT is left to mix with the new coolant?

Many thanks.
Click to expand...

The coolant you will be flushing out is OAT as is the extended life coolant that you are intending to add, so there's no problem at all if there is mixing between the two.

Richard
 
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XDC said:
On the basis that I don’t know what mono ethylene glycol is I go on the recommendation of 3 Volvo dealers, (1 not in this country).

Don’t mix green (older) with yellow (newer)
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The colours may be consistent with Volvo antifreeze but they are not consistent across different manufacturers. In my garage at the moment I have bottles of yellow, blue, pink, clear and green antifreeze, none of them Volvo. It's impossible to tell from the colour whether they are OAT/Longlife or IAT/2 Year and those are the only distinctions that matter. Although, having said that, I've mixed both types to some degree on occasions, although never 50:50, and never had any problems.

Richard
 
RichardS said:
The colours may be consistent with Volvo antifreeze but they are not consistent across different manufacturers. In my garage at the moment I have bottles of yellow, blue, pink, clear and green antifreeze, none of them Volvo. It's impossible to tell from the colour whether they are OAT/Longlife or IAT/2 Year and those are the only distinctions that matter. Although, having said that, I've mixed both types to some degree on occasions, although never 50:50, and never had any problems.

Richard
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I don’t really care what you have in your garage.

My links related DIRECTLY to VOLVO coolants coloured green and yellow and due to their different properties the advice is NOT to mix them.
 
XDC said:
I don’t really care what you have in your garage.

My links related DIRECTLY to VOLVO coolants coloured green and yellow and due to their different properties the advice is NOT to mix them.
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Except that the OP has a Beta engine and will be mixing OAT coolant with OAT coolant .... which means that, not only do you not appear to have a clue what this thread is actually about, but also I suspect that you have very limited knowledge of anything relating to boating which involves a modicum of good manners. :encouragement:

Richard
 
I recently bought a secondhand Beta 20 and was trying to unravel the monoethylene glycol/coolant puzzle. In the end i rang Beta and was advised that MEG coolant with OAT was ok.
By all means check with them as well. The more people who bother them the better the chance they'll improve their documentation ��
 
mogmog2 said:
I recently bought a secondhand Beta 20 and was trying to unravel the monoethylene glycol/coolant puzzle. In the end i rang Beta and was advised that MEG coolant with OAT was ok.
By all means check with them as well. The more people who bother them the better the chance they'll improve their documentation ��
Click to expand...

You are right that manufacturers should be clearer about this. However, it is not just Beta. My experience is that other manufacturers use the term "Longlife" rather than "OAT" or vice-versa.

Richard
 
Robih said:
As a slight diversion, could anyone advise how best to environmentally safely dispose of the old coolant?
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The dump at Port Solent accepts it.
It's classified as hazardous, so only certain recycling centres will take it.
 
RichardS said:
The coolant you will be flushing out is OAT as is the extended life coolant that you are intending to add, so there's no problem at all if there is mixing between the two.

Richard
Click to expand...

Is 'extended life' the same as long life?
Mobil list an extended life coolant which is good for 8 years/million miles/20 k hours, and 'all metals'.
Some OAT coolant is said to be not good with copper. The Beta engine has a copper alloy heat exchanger?
 
lw395 said:
Is 'extended life' the same as long life?
Mobil list an extended life coolant which is good for 8 years/million miles/20 k hours, and 'all metals'.
Some OAT coolant is said to be not good with copper. The Beta engine has a copper alloy heat exchanger?
Click to expand...

Yes, extended life is the same as long life is the same as OAT. I use modern OAT coolant in everything now, even classic cars, on the basis that the problems with the early OAT formulations have now been overcome. Of course, I'm not making this as a general recommendation and you won't find any manufacturers' recommendations for older engines for obvious reasons, but I've never had any problems. :)

Richard
 
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