O Day 28 radiator expansion tank

[waterking2]

I have a 1986 O Day 28 with the M-12 universal. There is no coolant expansion tank . Is this normal or should i add one ?

 

[Davidasailor26]

That’s normal, at least in the sense that it’s how ours was from the factory. Never had a problem from it in many years.

 

[GeorgeC]

waterking2.....I have a 1983 O'Day 30 with a Universal Model 20 (5416) 16 hp engine and mine did not come with the overflow tank. I installed a Westerbeke kit on my engine with the tank located in the port side lazarette so I can view the level of antifreeze without having to remove the cap on the engine.

 

[twodzusfittings]

Also have a M20. I bought a generic water tank for $11 from Amazon
Dorman 603-001 Coolant Reservoir Bottle, White Universal Fit
(some folks like pictures )

 

[RoyS]

My heat exchanger is the highest point my the coolant circuit. The filler neck on that heat exchanger is tall and provides sufficient space for expansion without requiring a separate expansion tank. Not all marine engines require an expansion tank.

 

[eherlihy]

In order to properly use an expansion tank, you need a bi-directional, cap for the coolant reservoir / exhaust manifold. The bi-directional cap allows for coolant to be pulled back into the cooling circuit as the engine cools.

 

[twodzusfittings]

@ eherlihy. Are you referring that the unit I have is an incorrect unit? I'm not following, obviously.

 

[Richard19068]

@ eherlihy. Are you referring that the unit I have is an incorrect unit? I'm not following, obviously.

The bi-directional (two-way) cap is the "radiator" cap for the coolant fill on the exhaust manifold. Not the one on the expansion/recovery tank.

 

[twodzusfittings]

Now understand, thanks.