I have a 1990 xj. did the hcv delete thing but didn't change the radiator. I'm putting in a radiator hose filler which is a radiator cap for the upper hose, " cheaper than a radiator" I was going to buy an overflow res but after I took off the shelf for the old pressurized res I found this just sitting under the shelf. I'm guessing someone used that for a res before I got ahold of her. my question is is can i use that temperately for my overflow until i can get a real one? thanks.