orifice bushing purpose on Single Point Drain System

[nateo]

Hi there. merc 5.0 mpi SPDS overheating.

The service manual indicates that the T fitting (where the 3 hoses connect) should have a bushing on a alpha or overheating could occur. My setup does not. Does anyone know what exactly this bushing does to prevent such an overheat? The manual I have is dated 2003, wondering if something has changed.

 

[alldodge]

Add your serial number to your sig, it makes things easier to look up. An with cooling system questions it helps a bunch to know if you have closed cooling, 3 or 7 point drain system. From memory and your pic I believe you have open cooling and 3 point drain system

Water flows the path of least resistance. The Tee fitting is designed to drain water from the risers during winterization. You do not water your main free flowing water going up to the risers first. The same issue is with the blue arrows in the lower block drains. The newer Tee's use a bushing insert, and the older design used a Tee with a smaller input. The newer design uses the same size hose




Over time these systems can cause you a cracked block

 

[nateo]

Add your serial number to your sig, it makes things easier to look up. An with cooling system questions it helps a bunch to know if you have closed cooling, 3 or 7 point drain system. From memory and your pic I believe you have open cooling and 3 point drain system

Water flows the path of least resistance. The Tee fitting is designed to drain water from the risers during winterization. You do not water your main free flowing water going up to the risers first. The same issue is with the blue arrows in the lower block drains. The newer Tee's use a bushing insert, and the older design used a Tee with a smaller input. The newer design uses the same size hose




Over time these systems can cause you a cracked block

I'm considering converting from 3 point to 7 point however the thought of simply adding a missing bushing in hopes of resolving my overheat problem is temping as well. About the cracked block thing. Is that because the 3 point setup doesn't cool it well enough (even when the bushing is in place)?

 

[Bt Doctur]

About the cracked block thing. Is that because the 3 point setup doesn't cool it well enough (even when the bushing is in place)?

It is because the block drains get plugged up with rust and scale and DO NOT DRAIN the engine. So when you think your done winterizing you havent done a thing to winterize the motor.and you end up with a cracked block. Best thing you can do is remove the system and go back to manually draining