Volvo 2020 (and others?) overflow pipe route.

[Bavaria 34]

There is a pipe that comes from the expansion tank just under the rad cap.

On my engine it drops straight down between the tank and the block and any overflow would go into the sump under the engine.

It doesn't overflow as I have the coolant level JUST under the plate in the tank and once did 3 days at "100" miles a day under engine with no ill effects.  Tank hot at the front, cool at the back.

A friend has been looking to buy a 34 or 36 and noted that in every picture of the engine the pipe seems to take a different route ... across the engine to the side ... to the front ... pointing upwards!

Does this indicate that the expansion tank has overflowed at some time and perhaps everyone has a catchment bottle?

Must stress this is not the engine with pipes leading from the rad cap to a tank above it such as you'll would get in a car.

Thanks

[Laysula]

I re-engined  a 2020 engine into a previous boat. I bought it new and fitted it myself. It came to me with the pressure relief pipe from the heat exchanger exiting straight down to the bilge.
My current boat has a yanmar engine and the relief pipe on that goes up to a small plastic tank. Not a pressurised tank.but just takes any excess from the heat exchanger.
In both engines neither has overflowed.
Leave well alone.

[Yngmar]

On our MD22 the overflow pipe goes straight into the bilge under the engine too. This is normal. I've added a small catchment bottle (kitchen cleaner spray bottle, as it's a nice flat profile). I have another one on the breather of the anti-siphon vent. Just so I can see what has been acting up if/when it does, rather than finding mystery liquids under the engine and having to play detective to find out what's been leaking.

For the MD22 there is an optional expansion tank kit for the coolant (with a different cap for the heat exchanger), but it doesn't seem to really need that.

[sy_Anniina]

Just a curiosity note:

Strange that MD22L has been installed both with and without expansion tank in similar aged Bavarias. Ours (2001 aft-cockpit 40) has MD22L with expansion tank 

[Bavaria 34]

OK, many thanks.

I'm going to assume that mine is the correct route but it MIGHT overflow, all the rerouted ones have overflowed and have a container to catch the result.

Wonder why they overflow?

As I said mine is filled to JUST under the recommended height, doesn't overflow, no ill effects. I think this was recommended to me by the first owner when I bought my boat when it was just 5 years old ... now nearly 20 ... so much going on at the time just scribbled notes so can't remember exactly what was said.

[Keweetoo]

A 1/2 L plastic milk bottle fits neatly into the bilge area under the engine on my B35 - just drill a hole in top and poke the overflow pipe in. I now fill to just under the ledge in the heat exchanger - any more and there is always some expansion overflow.

[Bavaria 34]

Exactly what I do ... less the bottle.

I feel happy to let my friend know that this is normal.

These are from Jeanneau's he was looking at.