Engine Ovrheating 1988 Supra
 

1988 Non Turbo. Overheats anytime ambient temperature is above 85. Never overheats below 85 degrees. HG tests indicate no problem. Have replaced radiator, water pump, fan clutch, thermostat, hoses, electric fan. No trace of water in oil. Any thoughts?

toyota service checked for a bhg once on my car and replaced the radiator .
it was a bhg , just because you hear bhg doesn't mean that engine dies over night , you can drive a long time with a bhg that is just a seeper. i bet over half the supras on the road have a bhg to some degree and the owners never even know it . they just keep adding coolant thinking " hey it's a turbo it must use water".
oh it's using water alright .
i like to check the oxygen sensor to make sure it's not coated white , grey is ok white is not .
when you say overheats . how do you know ? it's bubble like crazy in the resivoir bottle up front ? steaming ? where ?

so early in the morning when you first start it up do hear water gurgling in the dash ?