Hi im new to the board, and my brother has a 1987 Firdbird 305, 4 barrel quadra-junk, automatic.....

and its having some nasty overheating problems like when you drive it for maybe 10 mins it will start to bubble and steam into the over flow, i just did a cooling system flush on it, replaced the thermostat, waterpump isnt old(less than 8 months), looks like a newer radiator(aluminum), i think it has to do with the fan and how it doesnt turn on ever.. but im thinkin dual electric fans would be better than the stocker...

then the other problem is the car in park and neutral will run fine but when you stick it in gear it trys to die, i dont know much about carbs but im pretty sure it has to deal with it....

any help would be great thanks ahead...

 

Well if the fans arent turning on ever thats your problem right there.

As for it trying to die when in gear, what is the idle set at? sounds like its too low of your running lean from a vac leak or something.

 

Is the lower air dam in place? The one underneath the car that deflects air up to the radiator? Since these cars have no grille, this is crucial to maintain airflow to the motor...

Something to check, in addition to the fan problem.

 

i have the idle set pretty high so it wont die in gear and yes the black deflector is still there, i had to go and check to make sure he didnt rip it off somewhere..

 

make sure your cap is holding pressure too.

 

new stant cap

 

anybody....

 

ok so if you blew a head gasket what might it look like...might there be coolant comming from the head area where it meets the intake... what are upgraded that you can get for this motor, like intake, carb, rollor rockers, will anything for a SB chevy work?

 

Most things for the SBC will work. Exhaust is the first upgrade to do, then air cleaner (if it still has the stock single snorkel unit). Cam, perhaps intake (the stock one isn't that bad), and torque converter next.

But, you'd better solve this overheating problem first. Leaking head gasket will probably not leak anywhere to the outside, but can put hot gases directly into the coolant. Same with cracked heads. 10 minutes typically wouldn't be enough to overheat because of fans not coming on, but why aren't the fans coming on?

 

Check your oil. If it's milky, you've prolly got a blown head gasket.

 

Just a slight modification, it's not so much the hot gasses as it is the added pressure on the cooling system. In the difference between the >16 psi of the cooling system versus the 160+ of the combustion chamber, in the event of a blown head gasket, the pressure from the chamber would pressurize the cooling system moreso than normal, and in turn, that would be enough to open the pressure cap and cause coolant to enter the overflow.

Simple quick test: let the car cool completely and remove the radiator pressure cap. Have a friend or someone bump the engine over a few times (so the engine makes a few complete rotations). If you have a bad head gasket, you will see the coolant burp - like a sudden surge and some will spill out.

Here's a question that should have been asked sooner: At the point where coolant enters the resevoir, what does the gauge read as far as temperature? I.e are you getting hot enough so that the fan switch SHOULD be engaging the fans?

 

oil is not milky, checked that already... temp guage doesnt work...dont know why the fan isnt turning on, anyone know the wireing commin off of it so i can run a toggle switch or make it turn on in ignition..

 

Do you have a single or dual fan setup?

Could be as simple as a bad fan switch or a relay gone south. Try locating your fan switch. Should be in the passenger side cylinder head, between the 6 and 8 cylinders. Should be a single wire (forget what color). Unplug it and your fan SHOULD kick on. If it doesn't, the relay may be bad. Could also be a bad fan motor. If you have a single fan, try turning the A/C on. That also has a fan control circuit that over-rides the fan switch. If the fan works with A/C on, then the motor is good and whatnot.

 

Replace the thermostat.

Sounds like too much water in the system. Above the starter a little bit to the front is a plug or the knock sensor. It also serves as a drain point for the block. AFTER you drain the rad without burning your self then drain the block. Go to your local supermarket and buy distilled water and fill it up after it drained with a 50/50 mixture of coolant and distilled water. Let some of that drain and then put in a few shots of straight coolant just to make sure you don't loose an engine to the cold.

 

ill have to try draining the block but i already replaced the thremostat i was thinking bout just takin it out..

 

would the intake gasket leakin coolant have an effect on the cooling system overheating?

 

Bad Fan Switch - disconnecting the wire from the fan switch between #6 & #8 will not make the fan turn on - the key must be on and the wire going to the fan switch must be grounded for the fan to come on, at least on a single electric fan car.