My coolant filler cap is extremely hard to turn. When loosening, it's easy for maybe 1/4 turn, then there is so much resistance that sometimes I think I won't be able to get it off, and I'm pretty strong. Very hard to turn going back on too. I've cleaned both threaded surfaces in case the threads were gummed up.

 

RJ- Mine is tight too, I just left it be..

 

Plastic on plastic threads + pressure/vacuum. I always have a 4 inch slip joint for the job (BF water pump pliers).

 

How about a little silicone grease on the threads ??

Silverfox

 

How about with the metal filler neck, Oldblue?

 

You could install an aluminium 1 1/4 inch filler neck, much easier to open to check the coolant level.

https://www.fillernecksupply.com/1-1...nsor-adapters/

The straight spout is out of stock, but the next one down will work!

Double check and measure the OD of your OEM pipe, it maybe a different size in the SS

 

I'll check it out, thanks oldblue!

 

No problem. Those are less money then the GM plastic

 

Thanks SF, I just added some on the thread, & nice improvement !

 

Great Sleeper.... Sometimes we tend to overthink the problem !!!