Can someone explain to me why my overflow tank/cap starts out a 1/4 full and when just is running at normal temp the bottle fills up to the brim and is hard as a rock? I understand that its pressurized, but it would seem like if your bottle is expanding this much and its new that there is a flow problem. Im probably way off. Not overheating just the bottle expansion thing.

This is after Ive replaced water pump, thermostat and flushed the system. Is this air in the system? Ive burped once.

 

Got a green cap on it or black cap?

 

Black cap. I just bought a new bottle and cap to go along w hoses, water pump and thermostat.

 

Ditch the black cap and buy a 703-1396 from Napa.

 

What he said. The black caps would last less than a year. I got a green one about 2 years ago and never worried about it since.

 

I just bought bottle and cap about 4 days ago. U think they're just sub standard or of the box?

 

I dont have a napa where I live. Orielly auto does sell an upgraded cap that is pressure rated at 16 lb PSI. Do you think that would work? Although the Napa cap is pressure rated at 22 PSI

 

It's a volvo cap. It was used for years and years, so I'm pretty sure that you can find one at one the the other parts houses.

 

My blue/green Napa one leaked, then broke. One other poster had the same thing happen. Later I bought a black one from O'Rileys that seems to work fine. (Same Volvo part). Maybe I got a bad part? Idk. I couldn't really take it back and say the Volvo cap does not fit on my Jeep.