Make sure that your overflow hose-the ½ black hose coming out from under the radiator cap that goes to the radiator overflow tank- is well secured to the side of the radiator and not bowing out toward the headlight mechanism. One of my lights started to make a thumping sound when it when up at a certain point. After examining the operation, I noticed that the small hose was catching the left side of the headlight assembly, causing the mechanism to jam a bit at a spot. I secured the hose to the side wall of the radiator and all was well.
Potentially, if the hose kept on catching the side of the headlight assembly, it could eventually damage it and potentially rip the hose and shoot coolant out. Not recapturing the coolant could potentially cause engine overheat.

will check. thanks for the tip.
have enough problems without stupid ones like this.

Here's a picture to help see where it is and how to fix it.

I had the same problem with my Indy. P.O. had replaced the tubing and left it too long so it bowed out and caught the HL mech. I cut about 2" off the tubing, reattached it and all was fine.

The OEM setup has a small round plastic push-in clip to locate the overflow hose.

You are right. However, even with secured at that spot,it extended far enough to be pinched by the headlight assembly. I would do it as an extra precaution. I would also urge all to check the hose under the overflow bottle to make sure is not kinked.. Perhaps when I replaced the radiator the new overflow hose was softer and prone to get kinked. It stopped any antifreeze from getting in or out of the canister .