I got a new radiator the old cap didn't fit, got a cap from some Chevy and it fit. Ran it for while it was fine. I did a flush like last week.

But now when my truck gets warm enough it spits some of the coolant into the reservoir. They told me it was the cap it wasnt holdiny the pressure that didn't work went out got a new one. Still does the samething. Everytime before I start it, have to get the reservoir and pour the coolant into the radiator.