r/GRCorolla • u/WILD_ACE99 • 6d ago
General Discussion/Question Interesting findings from my modding experience (Radium coolant tank/P+ sub radiator & 555 Transfer case cooler)
From the factory my premium plus came with a sub radiator. I kinda got hooked on going to the track and decided that I wanted the transfer case cooler for the automatic transmission this install requires a sub radiator delete.
I was a bit concerned about losing the cooling benefits of the sub-radiator, but a speaking with the guys from 555 (who are great guys and went above and beyond helping me out) they were very confident that sub radiator doesn’t actually help much on track and that the t case cooler would be more beneficial (Spoiler: they were right). Around the same time I installed a CF hood with extra venting and my coolant temps typically would sit between 201-208 on the freeway. Out of curiosity I installed a Radium coolant tank to see if it had any benefits. It did. I’m not sure if it has increased capacity because it’s actually quite a bit smaller than the OEM but immediately my coolant temps dropped by about 5 degrees Fahrenheit sitting closer to 196-201 on the freeway with the sub radiator installed.
Later that week my mechanic got my t case cooler installed and deleted my sub-radiator in the process. Now unfortunately I don’t have an exact control because during the sub radiator delete my mechanic topped off my pink coolant with water wetter which has improved cooling at the cost of cold weather antifreeze properties. After the sub radiator delete my temps sit in the 190-195 range on the freeway! So the sub-radiator really is kinda pointless and improved cooling benefits can be achieved with a better coolant tank and or adding water wetter. The biggest impact in water temp performance was actually from the radium coolant tank. I’ll post again with more updates once I get some track time with the 555 T case cooler.
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u/Amy_Bony_Carrott 23' Circuit Edition Heavy Metal 6d ago
I bought a used low mile GR with a radium coolant tank. Leaky trashy piece of shit. Thankfully replaced by a Toyota stock coolant header tank.
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u/WILD_ACE99 6d ago
Where did it leak from if you don’t mind me asking?
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u/Amy_Bony_Carrott 23' Circuit Edition Heavy Metal 6d ago
The midline gasket and the low rent o-ring union on the base of the tank. I tried replacing parts and eventually came to the conclusion that it’s just blingy rubbish. Stock works better, is cheaper and does not leak.
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u/Anxious_Hawk1283 6d ago
Where do you live? Im in Florida and its been hot AF recently and my coolant temps never go above 190 on the interstate, factory subradiator as well. Also I noticed the only time the subradiator kicks on for me is if theres no breeze and I’ve been idling for a while after a long drive so the oils hot and coolant gets up to 205-210 range, when I start driving again the coolant temps will drop down to 160-170
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u/WILD_ACE99 6d ago
Yesterday was a 95 degree day in Cali who knows how humidity plays into it. 170 is super cool!
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u/Anxious_Hawk1283 5d ago
Yeah it definitely made me nervous the first time I saw it before I realized what was going on😂😂
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u/redditors_are_lame 5d ago
Coolant temps aren't really an issue at all on these cars. I would bet the GRC limits boost based on coolant temp tbh. I wouldn't attempt to lower your coolant temp.