Radiator Cap Substitute - good luck, be careful

[Grumpy]

Getting ready for Santa Fe I decided this year to not only change the antifreeze, but also the radiator cap. I've had what I thought was a small cooling problem- noticing in city traffic with other Voyagers that my bike got hotter faster, and the fan came on just a bit sooner than others' XII's, and mine's an '03.
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I checked a bunch of posts, and decided to try the STANT 10227 (this is a 'mini' cap, fits many 'metric' cars, and american small cars, from Mazda MPV, to some Lexus' and Chevy's, it's rated at 13 lbs). After not finding a STANT at several parts stores, I went with the NAPA equivalent. It looked to be a better made Mexico product than the one from AutoZone from Israel (a much lighter spring).
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All went well on the test ride for only about 2 miles. Stopping to check it out the 6" diameter growing green puddle under the bike couldn't be missed. The temp gauge was only 1 mark about the lowest bold one, and was and had been steady.. ##$! The cap was on correctly, and no fluid was coming from it or from the hoses that I could see. $#@#$@# time to get back home. :)
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A few hours later I gave up trying to find it. I did find a stone lodged between the fan housing & the radiator core, loosing the fan housing I was able to pop it up & out; the radiator seemed dry there, but I noticed that the bottom two rows of the radiator were still wet.
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I put the original cap back on and took it for another test ride the leak hasn't reappeared. Wish me luck, I'm going to try a much longer ride today.
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Oh, the NAPA part was $8 the KAW cap is $28 and one dealer actually has one in stock! But I'm sure the radiator & labor to replace it would be a whole lot more than $28 - I learned a lesson, I hope I got lucky somehow.

[Grumpy]

Good news, I went out for a couple of hours, including about 40 minutes in a parking lot doing low speed practice turns & panic stops- getting the gauge up to the point the fan began cycling regularly - and no problem. I'm very very pleased, surprised, and I'm NOT going to look this gift-horse in the mouth, and change anything else.

[Charlie from Illinois]

Sounds great Grumpy. Glad to hear things look good.