rxt exhust-hi temp alert

[underwdr]

Ok, I need a little feedback here. I have an 05 RXT with a Riva stageIII and an on going overheat issue. This seems to involve only the exhaust cooling system but has maxed my ability! First-overheat alarm was going off when at 65+ or occasionally on first acceleration (high). I took apart j pipe, removed and clr'd intercooler, and fully backflushed entire system hose by hose, and all is clear, water is flowing well. Took unit out and almost melted it due to high heat sensor not being connected (and not acknowledging red light on dash), this melted several components including the waterbox rubber insulating cover due to the excessive overheat. After removal of waterbox and inspection- noticed that the mid plate and baffle plates were blasted apart and or bent completly out of the way exposing the bottom of the can. There was a large piece of the metal plate loose and bouncing around inside, which led me to believe that this may have been causing the intermitent overheat issue due to its movement and possible ability to cover and restrict the water flowing out of the box. I have Installed new waterbox, sensor,and misc. other components and took to lake. Everything works, but I am still getting a high heat alert if I WOT for more than a couple of seconds.
Do I need to enlarge the small holes in the bottom of the J pipe? Maybe slightly restrict the outflow of the hose at the top of the J pipe to keep more water flowing to the waterbox instead of flowing out the backflush tube? Something else?
ANY ADVICE WOULD BE APPRECATED!

 

[Chi2005RXT]

Did you ever figure out the issue? I also have an 05 RXT and having a similar problem - hi temp sensor after running only a few minutes above idle when out on the water. Have flushed it out, taken out the J pipe and water box, checked all hoses and cleared them out using an air compressor, even drilled slightly bigger "pisser" holes at the end of the J pipe and still does the same thing. My next move is to replace the sensor and hoping that's the issue. Any help would be much appreciated!

 

[underwdr]

Yes it was figured out with success! The problem was that the intercooler(in my case an after market one from Riva) had an accumulation of crap plugging a few of the water tubes. It does not take much! Especially when you intake a tiny bit of stringy algea, add a couple of sucked up sand grains, and then pull the pwc From the water, and you end up with a dried up plug in one or more of the tubes. No big deal till you start to push the speed, result, insufficient water flow. Take intercooler out, go to good radiator shop, and have them use a high pressure reverse flush to remove debris and then get an inline filter trap to catch crud before it enters intercooler. Riva sells one.

 

[KK40384]

Did you ever figure out the issue? I also have an 05 RXT and having a similar problem - hi temp sensor after running only a few minutes above idle when out on the water. Have flushed it out, taken out the J pipe and water box, checked all hoses and cleared them out using an air compressor, even drilled slightly bigger "pisser" holes at the end of the J pipe and still does the same thing. My next move is to replace the sensor and hoping that's the issue. Any help would be much appreciated!

Your problem is you're overheating the exhaust out of the water by keeping the engine "above idle". A water hose just can't flow the amount of water needed to cool the exhaust out of the water if you rev the engine. Keep it at idle and you will not have this problem.

 

[underwdr]

Uh, no offense meant here, but he said out "on" the water, not out "of" the water...