bushwood

I have twin 440s in my boat. No overheat problems, just looking to keep the girls running strong. I have 160 thermostats which keeps my temps (when underway at 1900 rpms) around 170-ish. My question is; I currently have cheap radiator caps on my expansion tanks which are rated at 13lbs.

Would there be any benefit to the engines to having a higher lb cap and better quality? I do subscribe to the theory, "If it ain't broke..." However, when it comes to my 440s, if there is a better way, I'm all for it. The 18 yr old parts person who doesn't know what a 440 is, is no longer the person whom I trust for what's best for my engine.

Thanks

jacilynn_s

you can go to a 16 pound cap if you wish but it will put more stress on your cooling system. There is no reason to change the cap though both do the same job and if your engines run cool then just leave it.

bremereric

A 16 lb cap will get you to about a 234 degree boiling point. That means your tanks won't overheat until they get to 234 degrees.

PK1

As a general rule of thumb a 1 PSI increase in coolant pressure can net a +3 degrees in boil over. If you up PSI make sure the radiator, its hoses, clamps etc are all up to snuff.

440roadrunner

The thing is, if the exchanger, pump, block, etc in other words the cooling system is in good shape, there is LITTLE reason that the cooling in a marine installation should EVER be very taxed.

I would think you should be able to run them with MINIMAL pressure caps and keep things happy.

As others have said, more pressure simply stresses hoses, gaskets, etc, more

Marine engines are much different for cooling than "air" cooling as in cars/ trucks, which reach a limit in capacity. If a Marine engine runs hot, either the exchanger was undersized, plugged, dirty, or the pump is bad, etc.

bushwood

Thanks for the replies. I'll stay with what works.

bremereric

Good stay with the old saying. "If it works don't mess with it."