the first engine put in my 86 z28 was a new 305 i had everything replaced from the radiator to the transmission and i mean everything....any the rings washed out to bad reman...carborator......now just paid again for the second engine and it boils over every time u drive it and turn it off....everything is new and i have put over 5000 dollars in a car that is no better now then it was origanlly...here is the question try and fix it or give up cause i am out of money and am really pissed.....thanks for the advice.......

 

Sounds like an air bubble in the 2nd engine.... pop out the thermostat and fill the engine through that, then put the thermostat back in, seal it all up and try it again

 

if that doesnt work, get the radiator rodded out or get a new one.


*edit* nevermind, just saw where you said everything was new, so I have to assume the radiator is too

 

radiator is new...i replaced the thermestat today and when i took it off the engine was full of coolent in fact made a mess coming out of where thermestat was. the engine has about 200 miles on it...if u just let it idle it will go to 250-260 is that right?
ive heard new engines run hotter but for how long? any advice help me keep my third gen....thanks

 

take the t-stat OUT,
(not needed in the summer)
and tell us what happens.

 

Do NOT do that, or it will heat up and boil over even faster. Ask how I know. You NEED the thermostat in there. If not, the coolant in essence does not stay in the radiator long enough to transfer much heat to the ambient air. You need the thermostat as a restriction in the coolant system in order to get proper cooling.

 

what fan(s) do you have?

 

brand new 16" perma cool 2900 cfm electric fan

 

I ran a car without one for 3 weeks one time, and it never overheated.

 

today i replaced the 195 therm with a 180 and wired a manual switch to the fan so i can turn it on before 240 and seems to hold it at 200-210. by the way its 104 degeees here in so cal. does that sound ok ......thanks

 

JET and Hypertech both sell fan switches that turn on at either 160 or 180. Mine worked perfect until I burned the wire up with my new headers.

 

What is the timing set to? Is the car running lean at all?
I know you said everything was new, does that include the water pump too?

 

havent checked timing yet what should it be set to any ideas thanks. not running lean

 

There should be the emissions label either on the hood or the upper fan shroud plate. Mine is an 89 305TBI, swapped to an 87 350 TBI. Factory setting is 0º, but I keep mine at like 6º BTDC.

 

And how hot was it outside? I ran my car without it for a week in south Texas and I barely made it to the shop everytime because it heated up so fast.

 

on the overheating part:

check timing.

make sure you arnt running lean.

double check timing.



#1 cause of mystery overheating that everyone over looks: timing.

 

less anti freeze and more water will help cooling.. as will water wetter.. but system should handle a 50/50 mix and no water wetter and work fine. as for t-stat.. I ran mine without one for a couple weeks... but the weather here is quite a bit cooler.. all i can say is try it.
i programmed my computer to turn fans on at 95C .. think thats about 185-190F .. but you can get the fan switches that will do that for you. look for the total fan control article on here.. as for why its heating up.. check timing. since thats easy.. then make sure water pump is up to par even if it is new..

 

I live in illinois, and it was summer. So anywhere from 80-99 degrees usually around low 90's. Course this wasnt with one of the crappy stock radiators in our cars, this was in a 78 olds cutlass with a heavy duty big *** radiator. Might have made a difference.

 

definitely was the key, I have a stock replacement rad. with a single fan at the time. Guess you just got lucky, most of the time no thermostat results in overheating in record time.

 

I have taken the thermostat and cut the middle out (spring and stuff) and stuck that in.

Works wonders on overheating problems, better than anything I have ever used.

 

Not trying to be funny but are you sure the fans are rotating correctly(right direction). I had a friend that wired his to push and didn't even realize it.

 

when i put my hand between the fan an engine i can feel it blowing air over the engine therefore sucking air through radiator right?

 

mine runs 210 on the head and about 200 on the block year round and i havent had a problem (yet) good luck ... tao

 

Sounds right....since you installed the switch, turn it on and off right away, watch which direction it goes as it stops. That should tell ya.

 

ibwats,
I forgot to mention that you need to unplug the advance wire to check the timing. It should be a tan wire with a black stripe, right behind your pass strut mount. It comes out of the harness loom for a few inches and then goes right back in. There is a weather pack quick connector there.
Wait a minute, let me see if I can show you what I am talking about...
Oh yeah, if you already know this, my apologies.

 

Thats pretty good considering the temperature. You might even want to wire the fan to come on immediately, with the igniton (just wire it to an ignition-hot source). The only real downside might be a slightly reduced fan life, but I have run several electric fans that way with no ill effects. Do you have AC, and what does it do to the temp when its on?

 

when i turn on the ac on a hot day it runs 225-230 in traffic maybe 240. i still am running that break in oil so i dont know if that makes it run hotter

 

The oil shouldn't make any difference. A few things to check:
1) is the air deflector/air dam under the car in place and in good shape? If not, replace/repair it. You can also extend them a couple inches to pick up more air.

2) Is your aftermarket fan properly shrouded, and large enough to cover most of the radiator core? If not, that could be part of the problem.

3) Its been mentioned before; timing. Retarded timing can cause overheating.

I'd put a 160 thermostat in, at least for the summer, and make sure you have at least 50% water in the radiator. Straight coolant, or higher percentages can cause it to run hotter. You might also add some Redline Water Wetter or Royal Purple Purple Ice. Turning the fan on sooner should help also.