hey guys
i have a 1984 yota,,, 22r,carb, and it hasnt been holding coolent lately. its weird it will over heat fin the first 5 miles when it warms up then ill set and leave the elec. fan going to cool it off... but i had it over heat again on the way home... with that fan going....everytime i put antifreeze in it it will go into the over flow and ill look into the radiator and i can see the cores... it just wont hold it,,,, any thoughts??????? the only mod i have done latley is a baster 2 coil.,,, if it makes a difference,,,, but i hope some one can help.......... thanks guys

What tdo the radiator core tubes look like? Are they pinched off with deposits? If so, that could be the root cause of the overheating. You may now be seeing a head gasket leak caused by the clogged radiator (or whatever) and its the exhaust gas pressurizing the cooling system that is pushing the coolant out of the overflow tank. Do you have a temp. gauge? If so, does the coolant overflow first, then the temp rises or does the temp rise then the coolant overflow (i.e. boiling over)?

Here are some troubleshooting ideas:

http://www.arrowheadradiator.com/head_gasket_or_combustion_leak_test.htm

Sounds like blown headgasket or cracked head.

Let it cool completely, refill it with plain water(save anti-freeze, use plain water for test)....Leave cap off radiator and start engine. Look to see if water boils out once engine is running....if so, the head gasket is blown or the head is cracked....you might get a little overflow once the water pump starts turning, but it shouldn't contain lotsa bubbles or look like boiling water.

Make sure to drain water from radiator and engine after the test so's it don't freeze overnight.

awsome thastnks guys you rock... im going to try it in 5 mins...... but i have looked over it a bit already and no problems with the cores at all... no i dont have an exact meter just the stocker.... but there is no leaks externally.... just from when it overflows,,, duh!!! thanks again guys <img src="/forums/images/graemlins/cheers.gif" alt="" />

That's what mine did when I had a bad HG/warped head. Under load, it would push coolant out the overflow, filling the tank then out onto the road. The other test option is a pressure test, cap the radiator with a gauge/pump, apply pressure and see if it leaks down. Then run the engine and see if the pressure builds from the engine. It t gets over 15 psi or so, the rad cap will vent and let coolant go to the overflow.

sweet man thanks ill try everything else tomorrow.. youve helped alot. your a good man... see ya <img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" />

Pressure tester pic.....you can get one on eBay pretty cheap.

http://www.drivewerks.com/catalog/images/tools2003/MIT-4520.jpg

What ya do is install it in place of the rad cap and pump it up to cap rated pressure....then watch to see if pressure falls.

If pressure falls, look for leak....If pressure falls, but no leak, pull plugs and crank engine by hand to see if coolant squirts out of sparky plug holes.

DO NOT PUMP PRESSURE HIGHER THAN STOCK RAD CAP RATING or you can blow up yer radiator.

If no pressure loss in first tests, then leave installed and start engine....as engine warms, if pressure shoots up above cap rating, then it's the head gasket or cracked head...just doesn't show untill heated up.

P.S. Please don't call me no "sweet man" like you did 4Crawler <img src="/forums/images/graemlins/smile.gif" alt="" />

alright i wont say "sweet man" to you....... but i was really happy that i got some guidence..... well i put in a new thermo. today and no difference.... but it smokes alot more now too.... im pretty sure of the head gasket..... but im going to check the pressure soon.... im eating right now.... thanks alot you guys...... you ROCK... is that safe to say????? <img src="/forums/images/graemlins/kewl.gif" alt="" />

my 87 supra has this problem. i opened the rad cap, started
the engine and the coolant came out of the rad.
before that, a "gorggling" on the dash could be heard when
accelerating. i suspected it to be the hg but since no
water in oil, car was hardly driven. tstat was removed and
added coolant but was going to reservoir even before.
anybody replaced a hg on a 7mge engine? anything to watch
for? how was it? planning on doing it myself. gasket was
purchased already.