Good morning, I took my '85 GT out for about an hour drive, temps were all good the whole time. but i noticed when i got home that there was a decent amount of steam coming from the radiator. I've given it a good look over and made sure the caps were tight but i can't seem to find even a sign of a leak. anyone have any suggestions?

If you got a uv light you might be able to find it.

The obvious thing to check is to see if the coolant level is getting lower (over time) in the reservoir. You'll have to wait until the system cools completely, as the reservoir level rises and drops depending on coolant temperature.

This may be a totally different situation... but my hood has added vents, and if it's rained, water collects around the base of the radiator. When I then drive the car, and the cooling system gets good and hot, steam will come wafting up through my hood vents when I'm stopped at a light. It's of course the water on the outside of the now hot radiator being boiled off. The first time it happened to me, I thought the radiator itself was boiling over. Now that I know what it is, I enjoy the show!

quote Originally posted by Patrick: The obvious thing to check is to see if the coolant level is getting lower (over time) in the reservoir. You'll have to wait until the system cools completely, as the reservoir level rises and drops depending on coolant temperature. This may be a totally different situation... but my hood has added vents, and if it's rained, water collects around the base of the radiator. When I then drive the car, and the cooling system gets good and hot, steam will come wafting up through my hood vents when I'm stopped at a light. It's of course the water on the outside of the now hot radiator being boiled off. The first time it happened to me, I thought the radiator itself was boiling over. Now that I know what it is, I enjoy the show!

That's an idea I had initially too, didn't think of water collecting there which is why I didn't mention it, but if the cooling system was drained/spilled in the front, it could collect, along with rainwater or snow, which then boils off over the next half hour.

Can try UV Die but may not work or not w/o help. Many small leaks just can see for various reasons.

also https://www.fiero.nl/forum/Forum2/HTML/146198.html Hidden Fuel and Coolant Leaks...

To find leaks w/o heating up the system, You can use just about any pressure tester but most need an adapter to pump in back to get pressure then Rad cap "pops" @ 15-16PSI. If rad cap is bad & doesn't "pop" then do not pump the tester > 16-17PSI.
https://www.fiero.nl/forum/Forum2/HTML/145505.html Coolant Pressure Testing for Fiero.

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quote Originally posted by Patrick: The obvious thing to check is to see if the coolant level is getting lower (over time) in the reservoir. You'll have to wait until the system cools completely, as the reservoir level rises and drops depending on coolant temperature. This may be a totally different situation... but my hood has added vents, and if it's rained, water collects around the base of the radiator. When I then drive the car, and the cooling system gets good and hot, steam will come wafting up through my hood vents when I'm stopped at a light. It's of course the water on the outside of the now hot radiator being boiled off. The first time it happened to me, I thought the radiator itself was boiling over. Now that I know what it is, I enjoy the show!

Sounds like a fun time at least
Unfortunately that's not the case, i had a leak that i couldn't find before so i just folded and took it to a shop to be pressure tested. They told me the leak was just from the cap and they had replaced it. i see they obviously did replace the caps but seems like there's still a leak even though they pressure tested it? Sorry if that's a bit confusing.