vindicator101

I know this question has been asked 1,000 times before but I would appreciate the 496 experts out there double checking my thought process. My cooling water temp alarm went off the other day just as I was reaching WOT. Water temp guage was reading 180 and when I backed off the temp droped back to 160 pretty quick. Motor never went into guardian mode and alarm was not constant just lasted about 2 sec two different times. Exhaust felt normal to touch as did raw water pump housing and heat exchanger. After checking everything, ran back to the dock at 3,000 RPM with no problem though the temp did climb to about 170 while getting back on plane but came down after reaching plane. The outside air/water temp was cool, around 70 -75F. The motor is a 2001 HO with around 300 hours on it. The raw water pump was replaced about 20 hrs ago and has been changed every other season with no other overheating problems. Double checked water pump when I got home and impeller looked fine though my housing has never been replaced so it does have wear/scoring. It acts like the thermostat might be sticking but I've read on other post that they don't go bad. I've also looked at closed cooling water pump and it's not leaking from weep hole or any other place. So which one should I start with in replacing? Raw water pump with the thought it's loosing pressure because of wear on the housing, Thermostat thinking it's sticking, Closed cooling pump because of 300 hrson it and it's worn out???

Rockfish71

Check the water pick up on the drive and make sure you don't have weeds in there and check the coolers for weeds blocking the raw water side of things.

SDFever

None of your temps posted are high enough to trip the engine coolant code/alarm. Like said, completely check out raw cooling sytem and check to see what codes are in the computer from the alarm.

vindicator101

Good point. I guess I assumed since all other guages looked normal 180 on the temp was when the alarm came in. Thanks, will check.

Back4More

Had a friends water pressure sensor on the pump housing go bad...05 496HO