derekhale

Ok I have a 92 SC300 and it has a new water pump and hoses and new thermostat......recently it has been overheating and so I checked the water level and it is almost bone dry...added coolant and no problem. Somehow though it is losing coolant at the rate of a half gallon a week!!!! Ok so did a pressure test and no leaks from the hoses, no crack in radiator etc. etc. Full compression in all cylinders so not a blown head gasket.....wtf is going on??? Anyone had a similar problem? Thanks

soarer13oy

iTrader: (13)

Did you check your over flow tank? Might be a bad radiator cap.

Cleanshots

iTrader: (2)

look at the radiator cap dude.

BostonSC4

iTrader: (2)

Its evaporating from somewhere man.

derekhale

Well it is not leaking out of the cap. Could it possibly be coming out the overflow reservoir without the temperature gauge shooting up and alerting me to the issue? Gauge works fine also so it is not the temp sending unit either. This is a mystery problem I have never had before.

DaveGS4

iTrader: (2)

I've never used it, but I think they sell some sort of dye you can put in your radiator to help pinpoint links.

FutureSC

iTrader: (1)

Maybe check your heater hoses? Once I had a coolant leak out of the screw on the heater core. Long shot but just check for little things like that

1995Lexusc

iTrader: (3)

coolant travels to heater core, to throttle body to iac to egr and back. other spot is top and bottom of radiator radiator.

nosc400

I had the same issue right before my water pump went out...But, since you replaced that, I would agree with the bad radiator cap.