hi guys i just bought this 94GS 300 like a couple days ago and start to overheat on me ...i dont know y but ..all i did was , new radiator, new radiator cap, new thermostat, water pump ..and thats all...head gasket seems fine doesnt blows smoke and idle perfect (not rough)...everytime i turn on the heater the heater doesnt blow hot air instead cold air...and when every time the car get hot/overheat i turn off the car and coolant reservoir was boiling.......do u guys know what could be the problems though..cuz i lost and cant find what should i see and look for it to fix...it just happen 2 days ago ..and never happen before...thx guys and please let me know what could be the problems

 

anyone......

 

anyone.......

 

Sounds like you need to burp your system...park on a hill with the neck of your radiator higher than your heater core and warm your car up, any trapped air in the system will travel to the radiator neck. After that your should feel warm air out of your heater. Cold air indicates trapped air. After you start getting warm air out of your heater let your car cool....do not drive. And do a block test. It is a tool you can get from any auto parts store, renting is the way to go. The tool measures the amount of CO2 in your coolant system, that will tell you if you have a blown head gasket. If no to the head gasket, flush your system by circulating clean water while the car is running. Do not use a chemical flush...dagerous to aluminum bits and gaskets...hope it helps

 

Most likely you have a hairline crack on the head gaskets. I recently went through this with previous LS400. It ran fine, idle was perfect, new radiator/cap/thermostat, etc... but coolant mysteriously goes away and car did not smoke but it had blown HG.

 

the coolant doesnt go away though...i hope its not HG ..btw does ur ls400 coolant resvoir boiling/bubbling also when ur car overheat?

 

I second what boosted1st said. You probably didn't purge your coolant system properly when you changed those parts.

 

Yes it did. It drives fine for 5-10 miles or so then it starts to get hot. Once it reaches hot, coolant will start to boil and start leaking. It also didn't have classic symptom of headgasket which is gooey stuff on oil cap or smoking. It had hairline crack near exhaust side where pressure is built up then coolant is slowly burnt up then it'll start overheating. I hope your HG is fine but never know. If it was just air in the system it won't boil and explode like that. Good luck

 

If all the bubbles are out of the system then you have a clogged heater core,or a leaky heater core, check for coolant under the carpet., if none is present then you have a clog. To replace a heater core is a pain and very time consuming.