olds 350 over heating

[layedoutregal]

a friend of mine is having issues with cooling the motor..first off he got the motor from another friend who had rebuilt the motor, stock pistons, mild edl cam, and im not sure to what heads were placed on the motor..during this build and install we put a chrome valve covers on it and we needed a gasket. went to local napa. the problem we ran into is that the heads only only had 5 bolt holes to mount the valve cover on?? can anyone tell me what kind of heads these are?? another problem we might be having is he thinks the guy told him they were 307 heads that he put on a 350..will this work or can this cause the engine to over heat..he replaced the thermostat, radiator, and cap, water pump, and hes going to bypass the heater core.. he said is moving from 190-210 and the res is full, so i asked him if he burped the system and he said yes, but when he pulled the hose off there was no fluid in the hose and 2/3 full radiator..so if anyone has any info please help

 

[kingcolbert83]

First thing I would do since he has replaced most things and burped system is pressure test the system. You can basically pinpoint the problem by doing this. Pressure test the radiator cap first and then the system. If your not familiar with what to look for when doing this somebody at your parts store should be able to help you. If not then get back with us we will help. It usually cost money to rent the part but if you know somebody they usually let you use it right there. I know they do here.

 

[Blake442]

Top the radiator off again.

When it was initially filled, the block wasn't full... once the thermostat opens and allows the coolant to cycle through the motor, it will lower the level in the radiator. Fill the radiator back up and run the motor for a while, and when it get to operating temp, feel the upper hose to make sure the coolant is moving through it.

And 210* isn't that hot... My 455 runs at 210* all day. By comparison, LT1's like to run at about 240*...
People see 180* thermostats and think that the motor shouldn't go above 180*. This is not true. That is simply the temp that the thermostat opens.

 

[layedoutregal]

he has an intake 7111 edl, which states its for a 1980 1/2 until a 1985 307 heads..the casting number for his heads say on driver side 3A gm7 716 and on the other side has a 716 and a 554..so im thinking his intake is wrong? for the heads and what is those heads for?

 

[layedoutregal]

ok on the block the number is 5577523b, from what he was told its an early 350 76-77, so any input will help..

 

[megaladon6]

if you keep losing coolant, buy, borrow, beg or steal a system pressure tester. you could have a bad head gasket, and if the olds are like chevy's the intake gasket could be bad.
when does it overheat? at idle only, steady driving, hard driving, steady increase, jumping, etc?

 

[layedoutregal]

ok i checked the numbers their both block and heads for a 77 to 80 olds 350..so the intake should be good for use. were going to replace the fan and psi test the system i just hope it works, thanks for the input

 

[toe-knee]

alright.. heres my problem.. my 350 started overheating just recently.. but i think it was a faulty thermomast cause it would only happen every once in a while.... but the on going problem is when i run it hard the coolant bubbles out of the overflow tank once i either stop or slow down.. the temp gauge never got over 220.. when this happened. i got the rally pak cluster.. new radiator, water pump, new rditor cap.. so anyone with same problems..


like layedoutregal said we will do a few things to try to solve the problem.. im gonna go to autozone and see what i can get to read the temp of te water as its bubbles into the over flow tank.. maybe its nots over heating and theres a problem with the flow..

thanks for the replys..

 

[Blake442]

Check your fan clutch. A faulty clutch will not allow the fan to pull as much air as it is capable of.

 

[toe-knee]

thanks blake442.. we are gonna check that out and check the pressure this weekend if we have time..