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Running a Little Hot
raybo3
Administrator Posts: 5,459 admin
My 2002 342 is running a little hot at high RPM's. At about 3800/3900 temp will go up to about 200/210* and alarm will sound. As soon as I bring the RPM's down the temp comes down also. New manny's and risers, water pump serviced, antifreeze/coolant full. I am thinking maybe t-stat. I have never changed it and I have had the boat 11 years. Thoughts??????????????????? BTW I can run the boat at 3400 and temp stays around 180* normal temp is about 165*
2002 342 Fiesta Vee PC Point Of Pines YC Revere MA. popyc.org raybo3@live.com
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@raybo3, you need to keep a close eye on this and watch if the spike starts happening at lower RPM's too... while it is most likely something to do with flow/pressure, what you describe is also common for blown head gaskets- such as when the heads start to 'float', and the passage between cylinders is the culprit.
because you are closed circuit cooling, you can also stop by the parts store of your choice and pick up a test strip for your coolant- if there are combustion gasses present, this confirms blown HG's.
since you just put on new manifolds and risers, if i were you i'd carefully check the seal between block and manifolds for leaks... if the bolts weren't properly stretched in the pinch (weren't torqued carefully) they will stretch out under high pressure (high rpm's) and NOT snap back sufficiently. It may be you simple need to turn those bolts righty-tighty a quarter turn more- this will also cause spikes in temperature.
Perhaps reverse/forward/reverse/forward flush everything and makes sure to bleed to remove air locks.
as for the thermostat , if the coolant warms up and temp then stabilises , the thermostat is working but may not be opening fully. Easy to just remove it and run the boat to test.
good luck
If they are good my guess would be an obstruction somewhere.
i'd be looking at getting those test strips for your coolant, to see if there are any combustion gasses present... if there is, your HG's are compromised. another somewhat reliable way to check is to put a pressure gauge on the exchange- to see how much pressure is building.
something else to consider- that heat exchange is topped with a pressure/temperature sensitive cap... swap caps with the other engine and see if the 'problem' follows... caps on exchanges just like caps on radiators/degas bottles can cause all kinds of issues that look just like blown HG's.
craigswardmtb new pump a couple years ago and serviced every spring. My guy said the pumps still look brand new.....
That cap can cause pressure issues that manifests just like blown hg's (or is that hg'$?)... Lets hope for something simple.
Obstruction, unless collapsing hose, ought to been seen at all speeds compared to other engine. Pressure in system allowing air through cap is suspected issue... Running cooler at idle with good stat is a big concern pointing toward hg'$... Or... Cap... Pray for cap. Pray for collapsing hose. Pray for drew... I just tapped a keg of longboard approx 6 hours before crew shows up.. Maybe I'll see crew, maybe theyll jist see me.
PC BYC, Holland, MI