Gen 1 Cooling issues
 

I recently rebuilt a motor and decided to do head shims (instead of gaskets) and used that copper coating spray paint stuff. I am starting to worry that it plugged up some of the coolant ports in the block but anyway I'll continue...

I currently am running a vortec 350 behind an old water pump I had laying around with a new thermostat and a new 4.3 V6 radiator from an S10 with a new radiator cap (motor is in my S10). The only fan I have currently covers about half the radiator and is an electric push fan... it's not very good at all. Anyway, both hoses start to get hot, the radiator gets very hot all the way across, the top hose feels very pressurized. I don't think it's a intake gasket- I'm generating about 12-13 PSI of vacuum at 850 RPM.

Within the first 15 minutes of running the temperature just keeps climbing slowly, it never plateaus or never goes down. Right around 220 degrees I shut it down. I give it a little time to cool down, my coolant in the radiator is warm along with both hoses.


Forgot to mention i am not running a heater core.My thermostat has a little hole drilled in it b/c I don't have that tiny coolant port in the 1997 block and am not running a vortec style water pump with the bypass hose.
My system is just radiator, lower hose, block, thermostat, upper hose and back to the radiator.


Could my radiator just need to see more air flow from another fan or a flex fan? I find it strange that everything is getting hot but the gauge indicates it's not cycling.

1.) Which gaskets? Fel-Pro 1094's?
2.) You are sure that it is completely full? If you don't have an overflow/recovery tank you can puke out enough coolant to get low
3.) Is it carbed or still FI? If carbed, what is your ignition timing set at?

Forgot to mention I do have an overflow tank, it's not bleeding out anywhere and I can't imagine their is any air in the system since the t-stat has a hole drilled in it. It's carbed, set around 16* initial and 36* total, will do any fine tuning when I fix the overheating issue.

Which shim gaskets did you use?

uh they were made by mahle/victor reinz.

Your fan isnt big enough
 

get a bigger fan set up or use the original radiator that belongs to the car & the electric fan set up it came with. should be cheap from junk yard or do like me & head to harrys. Az :moon:

I think if it was a fan issue it would have the heating snowball effect... Hotter and hotter cycles. I'm starting to wonder if the thermostat is f'ed in the aye'. Didn't tinker with it today though.

you need a bigger radiator. the rad for the 4.3 doesn't cool all that well

I've ran small radiators before, that would have a snowball effect were each cycle got a little hotter. This doesn't even seem to cycle according to the gauge.

oh ok I must of had a dumb ass moment. Try a different thermostat. and another fan wouldn't hurt. Vortec motors had a belt driven fan I believe so that might help

I would check the thermostat in a pot of hot water.

Also, check your belt tension and make damn sure that old water pump is in good shape.

Without the thermostat and the addition of the flex fan it sits right around 150 degrees. I'm content for now. The truck will never be driven far enough (more than 30 minutes at a time) to affect it.