Questions and Answers
Nissan Coolant Loss - Revisited
Q. Hi Vince, Below is the previous question and answer that I sent and received from you. The radiator cap the mechanic installed was the correct one, because it has the return valve. Anyway, I purchased a new radiator cap/return valve and installed. The coolant is still not able to return from reservoir to radiator. Can you think of anything else that may cause the problem.
Thanks,
JeffreyA. There's only two things that would keep the coolant from flowing from the reserve tank into the radiator when the system cools off. The hose from the tank to the radiator is clogged or pinched, or the cooling system is not creating a vacuum when it cools.
If you take the reserve tank hose at the radiator and hold it lower than the tank, coolant should flow out of it. If it doesn't, the answer is obvious.
If it does, then the problem becomes a little more complicated. If the cooling system is not creating the vacuum, you have to figure out why. It's probably because air is entering it somewhere, maybe a loose hose or air is entering through the water pump seal.
I would also double check that the radiator is the correct one for the truck. If it's an aftermarket radiator the filler neck may be different and it may be holding the return valve in the cap closed.
Additional Information provided courtesy of ALLDATA
