2006 5.0L MPI Over heating - changed everything!

[maicoman]

QBhoy The problem with the single point drain system is the water flow thru the block and manifolds.The water has too many paths to follow to have smooth flow.Once the 7 point system is added only one direction flow is established.I was confident when I changed mine and when I gave my advise here.Not having a thermostat in this computer controlled warm manifold boat is not the way to go and it will still overheat.The single point drain is probably designed by the same person who routed the wires for the limit senders on the Alpha outdrives.

 

[JJB4]

UPDATE: Well, I got my drive back from SEI. They did honor the warranty (even though I didn't buy the upper originally), and they gave me a complete new housing (and also changed the bearings - thanks SEI !!!). Assembled it to the lower, installed the drive this weekend and - problem solved! Per the SEI break-in procedure, I can't run more than 75% throttle for the first 5 hours or so, but the boat ran 155 degrees @3000rpm all afternoon. Amazing, relieved, finally. Checked everything with IR temp gauge and all is well.

Maicoman, I appreciate your input, and I do agree that the single point drain system imo is not a great design. However, the boat is running great and I'm sick of working on it every weekend for the last 3 months so I'm calling it done until such time as it starts to act up again. I did actually buy the 3-point thermostat housing on eBay, so I have it as a spare if needed in the future (although I'm out $160 just collecting dust).

Thanks everyone who chimed in, it's been a long frustrating road that finally had a happy ending.

 

[Rick Stephens]

Awesome. Going boating - what a concept.

 

[maicoman]

JJB4 good job and happy boating !