SCGIRL400

My 95 SC400 has been overheating. I just bought it a few weeks ago and I am trying to get her back running right. Is it possible that its the heater core. I have bypassed the heater control valve and honestly can't tell if the heater is working. I'm in Florida and its right at 100 degrees today. I know the heater was not working before the bypass of the valve and now after the heat seems to fluctuate between Hot and not so hot...could it be a clogged heater core? If so what is the best way to bypass? Thanks so much for your help!

gunyvw

i dont know what you have changed to keep it from over heating but these things are to be looked at

thermostat... of course
fan funciton (you said you have an issue)
radiator and cap.... if old or worn out wont allow cooling
head gasket intake and exhaust.... one will allow steam (white smoke) and one wont even be noticed at all in some cases except for mysterious overheating.
freeze plugs... see below
block crack... see below
yes heater core if it is wet on the interior floor,...see below if it is blocked then bypass it.

you stated that you have uneven heating this means coolant IS escaping from somewhere.

mr/griffin

are you running a summer 25/75 mix?
return the car back to stock.
turn on your ac and see if your fan come on.
check the coolant level and make sure the mix is rite

the cooling system is very important and easy to diagnose

make sure you have a -proper- and working radiator cap the pressure from the cap is what keeps the boiling point down to much pressure is bad and too little is bad, also be carefull this system is easily dangerous. also you must fill the car while running bcus air pockets will build pressure and blow out the weakest point in the system (usually somewhere in the upper part of the system
r

ihiryu

iTrader: (7)

Have you checked your fan fluid? I know it sounds like I'm being a smart ***, but the hydrofan requires fluid. Dextron 3 IIRC

The heater on the SC is a bit weird, if it's low on fluid the heater actually gets colder. The heater, if fully working should almost feel like it'll burn your hand when it's on. I'm in Texas and I know for a fact when my heater is working.

Also a heater core leaking wouldn't cause it to overheat. But if the heater core was leaking, it should be leaking onto the floorboard

SCGIRL400

Heater Core is not leaking. We did bypass it because fluid was not running through the cooling system. Once bypassed and purged we got the coolant running through the system. I pretty sure we can reconnect where we bypassed and the heater will work. I think all it needed was purged but my husband wouldn't listen to me...lol We put some wetter water in and the temp isn't getting over the half way mark but you can still smell the coolant getting hot and all the hoses are extremely hot. We know the fan is leaking ATF we now are on to find where...the hose or pump and replacing those. Hopefully once we have that fixed we will be back to running stock! Thanks for all the help guys!

Triple C

iTrader: (2)

check your fan clutch. if it isnt tight and have resistance you probably want to get a new one (a Hydrofan is typically on a 1J unless you managed to do a worthless conversion and take your water pump out) If you bypassed the heatercore it would still run cool enough to stay in the 180 region. Do you have a 1J, 2J, 1UZ.....? it say SC400 but i herd hydrofan talk

ihiryu

iTrader: (7)

SC4 have a hydro fan too.....

SCGIRL400

Yes its a hydro fan on the 400