We originally copied the cobalt cooling system and routed the coolant into the top of the radiator and then out of the bottom.
It seemed to work okay but we would pull the radiator cap and find the radiator would have developed an air pocket at the top. This reduces the radiators ability to cool.
We switched the direction to put the coolant entering the bottom of the radiator and exiting the top. This eliminates the possibility of having an air pocket.
The reason OEMs don't like to do this is if the coolant level ever gets too low it can immediately stop flowing. Our cooling system would have to lose a lot of coolant before this would happen so as long as everyone takes a look at their coolant tank once in a while everything will be okay.
Dynoman56 has 11000 miles on his goblin with the radiator hooked up the old way.
Well I’m going to go out on a limb here and disagree for three reasons.
First and foremost, we all know heat rises. Go grab ahold of your radiator at operating temp. The top of the radiator is significantly warmer. I’ll go check later, but I’m willing to bet there is a solid 15-20° difference between top and bottom of the radiator. Maybe even more with the fan on. Why would you want to suck water into the engine from the hotter top side?
Second is Radiators almost always have a little air trapped in the top. It’s not a bad thing, if your coolant intake tube is down on the bottom of the radiator where there’s no chance that there can be a bubble. I’d much rather have bubbles trapped in the top of my radiator than getting sucked into the engine. Go look on your factory car right now. You’ll see the coolant about 1/2” below the cap. That’s all air.
Third is the cap on the radiator. Try as I might I can’t get it to seal. It will very slowly release pressure or suck in air when it needs too, even though my overflow tube is capped and clamped.
Don’t mean to thread jack. I’m sure you can get it to work either way just fine but I won’t be changing mine anytime soon....