Hey CL...while i was driving my car this morning, the temp guage went up right before the mark of H...popped the hood and saw little bubbles coming out of the coolant reservoir and i noticed a little leak from hose underneath the coolant reservoir ( not the dump tube ). Will that cause my car to overheat? looked through some threads and it looks like a common problem, can the bubbles on the reservoir be patched up? i'm guessing my next step is to get a new rad. cap., thermo, coolant flush, the hose underneath reservoir...any input is appreciated

Check your fan clutch. Mine died once and the car overheated. I blew the headgasket and ended up selling the car because of a $60 part. Every time I buy a used car I always make sure the coolant system is up to par. Replace the radiator cap, waterpump, thermostat, and fan clutch. Then I do a full flush with approved coolant. I was a bit unlucky with the SC after I replaced all of those parts, my radiator started to leak and I just replaced it with a new one. I replaced the hoses and got an OEM Toyota thermostat while I was at it. The car runs at a much cooler than before.

I dont know what it is about those tanks, but they just dont hold up to the heat whatsoever. They always seem to leak over time. I think you might have air in the system causing the overheating. Try and fix the tank with epoxy or find another one in the classified section.

His is an sc400 so no fan clutch as it is a hydro fan set up but make sure there is fluid in it and all is working as it should.

My coolant reservoir is cracked and I'm hesitant to buy another just to watch it happen again later. I'm looking into parts from other cars that might do the trick.

My Subaru had a similar sized tank with radiator cap on it that might do the job nicely. Nothing beats an OEM part that's available for cheap!

If anyone finds a substitute oem tank please post it here.

I found this the other day, has 2 fittings to hook it up like oem but its $70

Is this without a/c on? If so make sure AC fans ( if sc4s have them) are activating. If not could be issue. Either way sounds like your plan of action is spot on.

alright, i put fan clutch fluid, it was low but i'm still overheating, i just noticed that the radiator hose connected to the thermostat is cold, so i'm thinking the thermo is bad, i'm on my way to get a new one and some new coolant.

Yeah better change the thermostat, thats cheapest.

Was the thermostat stuck?

I have seen that somewhere before?