Hi

I own a 71 C3 corvette, small block.

The car is getting heated while driving in an ambient temp above 25 Celsius degrees.

I replaced the old fan with 2 new shrouded 12 inch, electric fans of 1730 CFM each.

So during a road drive, water temp rise up to 245 and I need to stop in order to cool down the engine.

When standing on idle thrust, the fans cool the temp down to 210. But during continues drive, not.

Any ideas to keep the temp around 210.

Jack

 

There are 101 ideas why, but I will start with this:

Overheating at idle is a Air Circulation Issue
Overheating at speed is a Water Circulation Issue

First, because your issue is at speed, check to make sure the lower rad hose has a metal spring inside that does not allow collapsing of the hose.
Fan belt not slipping?
Rad full of nasty crud blocking water flow?

 

Make sure all the seals are in place around your radiator too.

 

Burp your coolant system.
Air has a tendency to get trapped in these Corvette engines and will effect engine temps.
There are several threads on the procedure to properly fill and burp the air out of the coolant system.
Do all the things listed above, All good.
Wouldn't hurt to check your timing as well.

 

Check for the spring in the lower radiator hose, but it's likely that trapped air is stalling your water pump. I always fill with the car on a ramp (nose pitched up). Fill the engine first through the thermostat housing. When that's full, top off the radiator. If that doesn't work, try some of the other suggestions above.

Here are some similar threads:

https://www.corvetteforum.com/forums...ng-system.html
https://www.corvetteforum.com/forums...ng-system.html

Good luck!

 

 

is your black plastic "air dam" installed?
along with all the seals around and on top of the radiator?

 

i'm sorry, but i don't know what is "air dam"

 

In the pic theres a black thin piece of black plastic under the yellow spoiler in the front. Most bigger air dams are called splitters in Europe. The one in the pic is about 2 inches or about 1 cm.

The air circulation vs water circulation isnt totally correct. The air is being pulled through the radiator at idle and low speeds by the fan. At higher speeds it is forced thorough the radiator by the air flowing under the front of the car, up through the 2 holes below and behind the headlights into the cavity behind the grill. The air will go around the radiator if all the seals arent there.

The water is always circulating when the thermostat is open What is correct is that the lower radiator hose will collapse and prevent water flow and circulation through the radiator at higher engine rpm which will cause high speed problems as well. And if the radiator is full of crap it will cool less as the engine heat climbs.

As suggested, squeeze the lower radiator hose and see if its feels ridgid while the engine is shut off. make sure there is no gaps around the radiator and that there is a rubber seal between the radiator and where the hood closes down on the radiator support. And check and see if there is a little splitter under the front of the car. If there is a small rubber air dam and everything else is there and working, you can make a bigger air dam out of a piece of rubber which will force more air up through the openning and cool the motor. The one I made is 4.5 inches and keeps my motor below 180*. THe temperature you are seeing would suggest a couple of the above problems are occurring. I would also suggest testing the thermostat as they can stick open or shut.

 

Hi
Great, I’ll check and advise
May be you have pictures? Just to make sure I got it right…

Jack

 

Hi
Tnx,
I’ll try this. I already looked at some videos on YouTub
Jack