Coyote Coolant system with Moroso style expansion tank

[Junbug]

I made my first start the other day and all things are going well. Only "leak" is a very slow drip out of this small weephole on the bottom of the Moroso style expansion tank. I understood that it was somehow connected to the small hole in the seat of the neck where the radiator cap goes. I get a small puddle under that location after about 24 hours. I used a funnel when filling the overflow tank so I don't think it could be from that and its leaked more than that weephole could hold. I haven't yet run the motor long enough to heat up the coolant and have the fan kick on, and the coolant level is at about 1/4 of the overflow tank. I'm not sure how coolant could be getting to that weephole if it does indeed connect from the fill neck and exits at the bottom. Anyone have more experience on this issue? Will it potentially clear up once I heat cycle and get coolant flowing through the system?
Thanks,
-Bryan
https://thefactoryfiveforum.com/attachment.php?attachmentid=191298&d=1697601862

https://thefactoryfiveforum.com/attachment.php?attachmentid=191299&d=1697601862

[toadster]

I think you're just having some overflow/splash from the hole - let it run a few heat cycles - that's really the only spot that excess can escape IMHO

also, that cap looks slick can you show a pic of it?

[Junbug]

Thanks Toadster. It seems like more than overflow/splash from filling, but I've got a drip pan below it and it ends up with about a 4"-5" circle of coolant in it by the end of the day when I come home from work. I do need to heat cycle it to ensure I've got enough coolant circulating in the system. Plan to add my exhaust pipes first so I stay friendly with the neighbors. What level should the fluid be at in the expansion tank once I've heat cycled it a few times? I recall roughly halfway full from reading others build threads.
Also the billet cap came with my expansion tank. Its a UPR product for 15-22 Mustangs... I'll PM you the link but my quick search this morning didn't show that they sold the cap separately.
-Bryan

[toadster]

I've filled my tank up to just under the cap, no overflow as of yet, but I still need to get the whole engine up to temp (whole other story)

[Nigel Allen]

I put a Moroso tank on mine about 6 months ago.
Filled it about 3/4 full after initial heat cycle. The next few drives, a little weeped out of the overflow hole after shutdown. Recent checks show a bit over 1/2 full when cool. No more coolant weeping from overflow.

[BEAR-AvHistory]

I've filled my tank up to just under the cap, no overflow as of yet, but I still need to get the whole engine up to temp (whole other story)

If you are using a closed system you should allow for some expansion. Would not put more than 1/2 full. Only time I have added any coolant to mine is when I replaced all of it. Has been refilled with fresh twice. Have not lost or added any between replacements.

[Hoooper]

If you overfill the tank it will make the right amount of space after it gets fully warm the first time.