Just installed aftermarket radiator in my 2000 civic dx sedan
Went well until I tried putting the old cap on.
It was too small.

Any idea where I can get a cap for a 1.13 inch diameter inlet? Preferably an Auto Zone/Pep Boys/Advance Auto so I can get a ride on my break from work today. Car has been stuck at work for a week now.

 

Have you called your local parts store? I'm sure they can sort through their inventory for the right size.

 

I'd order the matching cap for your radiator at the same store you purchased it

 

would have if they had specified the radiator didn't come with a cap.

 

I'd call back the store and yell at them for poor documentation and force the manager to send you the matching cap