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After having driven cars for about 60 years now, I figger I would have a pretty decent idea on how to remove a conventional radiator cap. NOT SO on this C3 of mine. I can twist it to its initial "pressure bleed off" position.....but from there, nothing...no matter how much I pull on it, push on it, twist it...that cap will go no further.
So after y'all quit giggling, someone please educate me as to the proper procedure in removing the radiator cap from my '79 C3.
I even tried some channel locks on it, to no avail....was afraid of actually breaking something. All I can do is twist it BACK to its "locked" position.
Now find a spare kid becomes the problem. I had too. I’m sorry. It’s really no laughing matter.
the cap does that so if it was full of hot stuff that it doesn’t fly off par boiling people.
try this. Place open palm on closed cap. Twist at wrist. You will feel first keepers come loose. Then push down a little harder and turn some more. About 90 degrees. Cap should be able to be wobbled off.
good luck.
My 73 with factory air conditioning and stock radiator had an aftermarket radiator cap on it. It was extremely hard to turn and even remove, had to use Channel lock pliers. I believe the spring was rusted and would not allow the cap to be pushed down. I solved the problem and bought the correct AC Delco cap from Corvette America and now can remove the new one with my palm, no tools required.
The down force applied to the radiator cap can be pretty hard depending on the condition of the spring, especially when you are pushing down and also turning counter-clockwise. My wife has a 6"x6" rubber coated pad we use for removing jar lids, which helps provide some grip to the surface of the aluminum radiator cap if you have one or something like it.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I just had this same issue. Its hard to get in there with the angle and the hood as it is on mine but you just have to wiggle it, then push down and twist. Probably has a burr under there.
My newest cap is actually a little easier to remove than the previous ones but it can still be a bear. You might try upgrading to a new cap to see if there is any difference. My previous cap was so tight and hard to remove that I ended up buying a cap removal tool - this one:
The extra "step" just before that cap can come off was put there so the cap wouldn't just blow right off if it was loosened while still under pressure.
I've had some caps that were almost impossible to push down to get that second step and others that weren't too bad. Currently I use a red lever stant cap which is a little easier, partly because it's on the remote tank right tight to the fender lip. I believe some of the problem is that you can get the cap crooked there fairly easy with one side starting over the step and the other gets wedged into the side of the other one
You can use a pair of needle nose pliers and twist the leading ends of the two lips on the underside of the cap out (down) a little to provide a "ramp" to help get the cap started up over the last bit. That way you don't have to push it down quite as far to get it started and as you turn the cap it helps pull it the rest of the way
Radiator Cap
