Abiram

I just got the radiator and a few hoses replaced and have driven the car about 50 miles. When I was out on the road the car overheated and turned off. After I brought the car back home it seems to be overheating immediately. I really can't tell what's wrong since the car drove fine on the highway a day ago. The car has no problem starting after it cools down and symptoms of any head gasket or block damage.

780Griffin

When you replaced the radiator hoses did you bleed the coolant system of air?

RudysSC

SC's can take a bit to bleed. A large funnel like the one above is super helpful. I'll also park or jack the front of my car up a bit to raise the front of the car as the "high point" to help get air out of the system.

GAsc300

Check coolant level in reserve tank and in radiator (when cool). No leaks and levels fine then…
burp system

Cooling fan spinning? Sc300 (probably sc400 too) has pulley mounted fan so it should be always spinning

check thermostat:
Sc300 (sc400?) has thermostat in lower radiator hose, so if overheating or running hot and upper hose is hot as hell but lower hose only warm, worth removing or replacing thermostat

bad water pump next avenue I’d investigate after these

Since problems just began soon after radiator work, I’d bet coolant levels, air in system, or thermostat most likely issue. Hope you didn’t do damage to engine from it shutting itself off from high temps.

Good luck,

GAsc300

GAsc300

Just wondering what happened for you?

I recently had running hot issues in my 93 sc300 after replacing thermostat. Coolant was squirting out of overflow tank cap vent hose. Lots of bubbling too. Thought maybe I didn’t burp air effectively or put thermostat in wrong. Redid job and tested new thermostat in hot water too, opened and closed well. Put back in, same problems.

within past year I did timing belt and water pump, new hoses and all has been good cooling wise til this.

Then I realized I replaced radiator cap with new aftermarket one during this job. I never liked the newer styles without that dangle piece the oem had. Anyway, when I put the old Toyota cap back on, everything worked like a charm. Crazy.

My lesson: stick with Toyota stuff for radiator cap and don’t forget to think about bad or badly fitting cap as cause of cooling problems. If cap doesn’t hold pressure well, coolant will have lower boiling point and may be expelled through reserve tank after engine heats up; if cap holds too much pressure, it puts stress on radiator and hoses. Cheap fix if it’s the cause. I’ll for sure order a backup one or two next time I get Toyota or Lexus stuff: part #16401-20353.