So my radiator was leaking so I replaced it as well as put on new hoses and clamps, and now I have this new issue where the coolant that the goes into the reservoir tank while the engine is running does not return to the radiator. What could be causing this? There are no visible leaks and I dont think the issue existde before changing out the radiator

 

Did you replace the radiator cap at the same time? If the cap is faulty, it may not be sealing correctly so the vacuum that draws the coolant back into the system isn’t forming.

They can be tested but they’re also cheap - usually less than $20 - and it’s recommended to replace them with the radiator anyway.

 

Yes I replaced the radiator cap twice actually, with two different aftermarket caps with the same pressure rating as the one that was on there in case the first one was defective.

 

Did you make sure to bleed the front and rear heater cores?
How much of a difference are you seeing?
Are you sure the system is filled to capacity? It’s not uncommon for some to be left in the reservoir tank - in fact it’s good that there is.

In a correctly operating system, the only way for the coolant to be drawn from the reservoir is when the engine cools down and a vacuum is formed. Then the valve in the cap opens and allows it to flow.

If the system is full to capacity, the only things that can affect the vacuum are a leak or a faulty radiator cap. If you’re not seeing any leaks, it could be internal to the engine - check the oil and trans fluid for signs of coolant contamination.

A pressure tester can be rented at many parts stores - it may also have the adapter you need to test the cap (new doesn’t mean good - it’s unlikely you got 2 bad caps in a row but don’t rule anything out yet). Pressurize the system to the rating on the cap and let sit for 2 minutes - perform this check cold and hot - if it holds pressure for 2 minutes, it’s not leaking. If it doesn’t, look for the leak.

 

Not sure, how would I go about bleeding the front and rear heater cores? Pretty sure I filled the system to capacity, but Every time I open the radiator cap I have to add a pretty noticable amount of fluid, drove about 60 miles the other day and had to add at least a Quart. But the overflow tank never loses fluid, the level either stays the same or increases. I will try to get my hands on a pressure tester and try that, thanks for the help

 

To bleed the heater cores, run the engine to operating temperature, then turn the heat to high speed on the panel mode. Run it this way for at least 5 minutes for the front and 10 minutes for the rear (you can let it idle rather than drive it if you prefer, but if you have auto temp control, roll the windows down to keep it from shutting off the heat).

 

Rented a pressure tester and in 5 minutes the needle on the gauge went down slightly like from 16 psi to like 14 or 15
, still not seeing any leaks though