TEMPERATURE problem

[Dimitri]

Dear all Supra LOVERS

Last 3 times I ski with my com 90 I notice that the temperature is going up to 220 and then after a while to normal (160) and some times less than normal and again hi and low....
First I look for restrictions in the hoses, then I inspect impeller, finally change thermostat, and the problem is still there. I think that the gauge is OK (ground check), Does anyone have any idea what is this? I guess is the water temperature sending unit but I'm not sure,
If anyone have a previous experience with this problem will help my very much

[Brian Raymond]

Check the in side of the transmission cooler. It is like a small radiator and is compromised of small holes on the inside. This will clog with small sticks, weeds and even sandwich bags. Keep us posted. Brian Raymond

[Salty87]

i'd be real concerned if you're hitting 220, have you tried touching a riser to see if that's at all accurate? smell any rubber burning?

new temp sending units are cheap, $10-15

any water weeping from your water pump?

one quick option for peace of mind while you're tracking this down is to get a hand-held IR thermometer, temps that high are real bad.

[Dimitri]

THANK YOU BRIAN & SALTY

The cooler and tubes are clear (was the 1st think I chek + impeler), riser gaskets are new. But the strange think is that the heat is increaseing (220F) and decreaseing (160F) and, with my simple mind, I guess that if I had a serius problem with overheating (suchas head gasskets failure and water in oil pan) the temp shoulden't go to normal operation (160F) while I'm running the boat. Is that correct? Thats why the first think come in mind was the thermostat but wasn't. Any way next time I will trace the temperature with thermometer and see what happend. But if the temperature is real I don't realy know where to look for correcting the problem....

Dimitris

[Salty87]

i think if i were you, i'd make sure that the engine isn't really getting that hot. if it is, you could damage it. you should be able to tell by hand if the risers are burning up or running at a normal temp....don't burn yourself though. you should be able to leave your hand on the riser for a few seconds, if it's too hot to touch then you're running too hot.

you might be sucking in air somewhere too and losing water flow. if the water can't circulate, it won't cool anything down.

[Dimitri]

Dear Salty

You can tuch the risers are not that hot but I dont know what happening inside the block. I havent thaught of sucking in air I will chek this out too

THANKS I will keep posting...

[kcsideways]

Did you replace the raw water pump (impeller housing) gasket and all housing screws torqued down? All coolant hoses firmly clamped down? Has the impeller ever disintegrated in the housing and sent the black rubber pieces through the motor?

[Dimitri]

Last time i repace the impeler 2 fins where missing and I never find them But how you take them off from the block?

[Dimitri]

Just came back from the lake and I find out that the temprature problem was FAKE, I was thinking that is impossible that the temp gauge to go hi and low the same time. So I measure the temp levels with special instrument and it was normal!!!! Tank God.

Its time to replace the valve or the instrument.

THANK YOU ALL FOR YOUR REPALYS

Dimitris