Bleeding Volvo D2-40 cooling circuit

[svlamorocha]

Has anyone flushed and refilled with coolant one of these new Volvos? Any tips regarding how to purge air out of the system?

Is it correct that you have to fill from the plastic overflow reservoir, (lift that reservoir also) and cannot open a cap in the block itself?

Thanks!

Charlie

[OceanSeaSpray]

I have filled my D2-40 from new and there is no need to bleed air from the block. If you look closely, the cooling system is very well designed with no airlocks and my engine is installed dead horizontal.

Fill from the small plastic header tank in place and let the coolant find its way into the block. It takes a few minutes. From memory, there wasn't even a level drop in this tank when I started the engine, so don't overfill to allow for it.

As long as you don't have a weird installation with a saildrive and the front of the engine lower than the back, it should be a complete non-event.

Regards.

[colemj]

I don't have direct knowledge of the D2-40, but lots of experience with its predecessor, which is quite similar.

If you have water heater loops off the engine, you will need to make sure these do not air lock. Other than that, I don't see why there would be any airlocks that wouldn't be cleared through the heat exchanger tank as normal.

I don't see any reason to have to fill it from the overflow reservoir. That just leads straight to the fill cap anyway. In fact, that seems like a very slow and complicated way to fill it. Just fill like normal through the fill cap. Pour somewhat slowly so that air can gurgle to the top as it fills. Just like any other engine.

A saildrive will have nothing to do with it - that isn't part of the coolant system nor does it cause the engine to be at an angle.

Your Volvo owners manual should have coolant change instructions.

Mark

[OceanSeaSpray]

Originally Posted by colemj

I don't have direct knowledge of the D2-40, but lots of experience with its predecessor, which is quite similar.

...

I don't see any reason to have to fill it from the overflow reservoir. That just leads straight to the fill cap anyway.

...

A saildrive will have nothing to do with it - that isn't part of the coolant system nor does it cause the engine to be at an angle.

Your Volvo owners manual should have coolant change instructions.

Mark

Something could be said about speaking from actual experience... try to find the "fill cap" on a D2-40 and come back. These engines are filled by the header tank, where the only cap to be found is located, and it works extremely well. The new D-series engines are rather different than the old MD ones.

Saildrive installations sometimes result in the engine being installed back to front in the boat, and... sometimes with the front of the engine slightly lower than the back, but in fairness I think I can only remember one such instance. They are normally flat.

[svlamorocha]

Originally Posted by OceanSeaSpray

I have filled my D2-40 from new and there is no need to bleed air from the block. If you look closely, the cooling system is very well designed with no airlocks and my engine is installed dead horizontal.

Fill from the small plastic header tank in place and let the coolant find its way into the block. It takes a few minutes. From memory, there wasn't even a level drop in this tank when I started the engine, so don't overfill to allow for it.

As long as you don't have a weird installation with a saildrive and the front of the engine lower than the back, it should be a complete non-event.

Regards.

Thanks. I was helping someone who is far away; apparently the airlock was not in the engine proper but in the (add-on) water heater, which is fairly high (top of it level with top of engine). This "theory" is compatible with what you stated. Thanks again!

[svlamorocha]

Originally Posted by OceanSeaSpray

Something could be said about speaking from actual experience... try to find the "fill cap" on a D2-40 and come back. These engines are filled by the header tank, where the only cap to be found is located, and it works extremely well. The new D-series engines are rather different than the old MD ones.

+1. I attach photo just to make the point.

Only caveat is that depending on where the plastic tank is installed (this is specific to each installation), there may be a high point in the hose between plastic tanks and heat exchanger, hence when filling the system from scratch you need to lift the plastic tank to eliminate that high point and let air out.

[colemj]

Originally Posted by OceanSeaSpray

Something could be said about speaking from actual experience... try to find the "fill cap" on a D2-40 and come back. These engines are filled by the header tank, where the only cap to be found is located, and it works extremely well. The new D-series engines are rather different than the old MD ones.

Fair enough. I was correct about the lock in the water heater though

Mark

[svlamorocha]

Thanks!

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