I just installed a dual core half size radiator into my car and it is just a slight bit too tall. The hood closes but it presses against the radiator cap. I'm worried that I am NOT getting proper overflow from my radiator cap due to the fact that the hood is pressed against it I drove it for a while and the radiator is warm or hot but the line leading to the overflow tank is not warm and the overflow tank itself has radiator fluid in it from prior to me changing the radiator out however the radiator fluid that is in it is not warm because the tank itself is cool. I put the radiator cap on my voice on the workbench and press down against that and was still able to move the spring-loaded mechanism underneath but I am wondering if the hood pressing down on the top of the radiator cap is causing it to be unable to vent. Any responses are appreciated.

 

If you think the cap is interfering with the hood, use clay and place it on the cap, and close the hood. Press down slightly. Open the hood. If the putty you applied is smashed completely flat and has next to no thickness, your radiator is in fact, too tall. You can remedy this by cutting the rubber feet on the core support, or by denting the structural hood members that are interfering. Is the cap in the same position as the old radiator?

The hood hitting the cap will have zero impact on the overflow tube operation, because this spring is loaded INSIDE the cap itself. You will probably break the radiator neck long before losing coolant flow to the bottle.

Coolant will only flow into the bottle when the pressure in the cooling system exceeds the pressure on the cap, which will only really happen in the summer months. In cooler temperatures, the overflow system may never open at all, but only draw coolant in as the temperature outside drops.

If you are really concerned after that, run the car at idle until the cooling fans cycle, with the heat off inside the car. Turn off the car, and let it sit for a few minutes. Then, using gloves, squeeze the upper and lower hoses at the same time. If there is enough pressure, it will force the overflow spring upward, and vent coolant to the bottle.

 

Thanks. I went ahead and cut out a small portion of the inside of the hood to accommodate the cap. I intend to put a traction bar in place of the stick frame mount which will allow the radiator to sit slightly lower. Thanks again for the input.