Perkins 4-108 loosing coolant

[Sindbadly]

My Perkins 4-108 keeps pushing coolant out around the Bowman heat exchanger tank cap. I replaced the old cap, but it hasn't improved. A mechanic said the tank shouldn't be full but then the top of the heat exchanger is not covered so can't be cooling efficiently. Another said it should be full and will push any extra coolant into the reservoir tank when it heats up, which makes sense. The cap is a 9.0 pressure.

I am sure with all these engines still out there that someone has an answer.

[marcjsmith]

I’ve got the bowman he/exhaust manifold version. I’ve topped it off before and it ends up pushing some fluid out, maybe a cups worth…

Seems to do just fine with a little bit of coolant missing. No overheat problems.

[Sindbadly]

Thanks. I suspect that when the coolant heats up it must expand enough to cover or mostly cover the heat exchanger inside. The temperature gauge doesn't seem to rise so it must be ok.

[MWGDVC]

Sindbadly,
I added a coolant recovery tank to my Bowman equipped 4108. Mine stays full to the top when cold, (the only time one should remove the cap). Be sure your radiator (heat exchanger) cap is equipped with the recovery valve. This is a one way valve in the centre of the smaller diameter rubber gasket and allows the coolant to return to the heat exchanger when it cools down. Also there must be a larger diameter rubber gasket under the cap top. If coolant is pushed out of the overflow, there must be a sealed system for the cooling system to draw the coolant back in as it cools. If there is even a slightly loose hose clamp anywhere in the fresh water circuit, it will suck air, rather than draw the coolant from the recovery tank.