add closed cooling

[scoflaw]

Buying a fresh water 2005 merc 5.0. It has raw water cooling now. Talked to my local merc dealer about adding a closed system to it. He says it's not that easy and requires a different ECM. That's a tough one to believe. Anybody heard anything like that?

 

[Don S]

Re: add closed cooling

He says it's not that easy and requires a different ECM. That's a tough one to believe.

He's absolutely correct.

 

[wi4x4man]

Re: add closed cooling

Are you running in salt water?

I could see using that in salt water, but it just adds more complexity. About the only advantage is that if you are in a cold area and it freezes and you forget to drain the water, you won't crack your engine... Just the heat exchanger components.

 

[Scott Danforth]

Re: add closed cooling

yes, with an EFI motor, the ECM gets changed.

I would simply add a superflush kit vs a closed cooling system unless you keep it in salt water.

 

[md240z]

Re: add closed cooling

Does a 2000 5.7 EFI BROVO 2 need to have its ECM changed too. I have this running with a San Juan MC331 system on it and it seems to be running ok. The only thing I am concerned about is that the temp runs a 175 at 3,000 rpms and starts to climb when I go up to 4,000 rpms. The engine was running at a constant 160 before I converted. I am thinking that I should have gotten a Monitor MFH-5406. Monitor install instructions say that the MFH-5406 system will run between 160 and 170. San Juan docs to not say anything about running temp other than the motor will run hotter. Does anyone know what the highest safe operating temp is for a 5.7 EFI?

 

[Volphin]

Re: add closed cooling

The reason the ECM is changed is due to the higher operating temperature of a closed system. It requires a different air/fuel curve during open and closed loop operation. Timing advance may be tweaked as well.

Raw water temp alarm will sound at 180-185 on a 5.7

V

 

[md240z]

Thanks V,

When you say the ECM needs to be changed. Does that mean that there is a computer software ajustment that needs to be made to the ECM or you need to get a hole new ECM unit?