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Sounds like an option once the car is out of warranty .
Have you got the details?
Replacing the oem radiator with the koyo won’t affect your warranty. Not only is it all aluminum but it’s also thicker and holds more coolant. On my personal car I added the koyo radiator, trans cooler and oil cooler. Never had any issues with over heating or concerns of coolant and trans fluid mixing since all three are separate.
Thanks. Now need to find these from a UK supplier. In other news the OEM rad in the UK is on back order and for now a temp date given when it will come in stock. No hard confirmation of when it will.
Replacing the oem radiator with the koyo won’t affect your warranty. Not only is it all aluminum but it’s also thicker and holds more coolant. On my personal car I added the koyo radiator, trans cooler and oil cooler. Never had any issues with over heating or concerns of coolant and trans fluid mixing since all three are separate.
For the oil cooler that you installed (assuming you went with RR Racing) did you bypass the factory oil cooler (note, I meant factory heat exchanger, i.e. the donut)? Been trying to do research on it and figure out what's best, bypassing or not.
Last edited by kzlflash; Aug 28, 2020 at 07:14 AM.
For the oil cooler that you installed (assuming you went with RR Racing) did you bypass the factory oil cooler? Been trying to do research on it and figure out what's best, bypassing or not.
Our cars don’t come with an external oil cooler. The only cooler our car does come with is a tiny little transmission cooler. I removed it completely and just used the oil and trans coolers from RR racing. Looks way cleaner and with the size of the trans cooler that RR provides you don’t need to use the oem one. I’ve ran my car in 120 degrees with no cooling issues at all. With the external trans cooler you don’t have to worry about it mixing with your coolant anymore. All 3 coolant, trans and oil are separate now.
Our cars don’t come with an external oil cooler. The only cooler our car does come with is a tiny little transmission cooler. I removed it completely and just used the oil and trans coolers from RR racing. Looks way cleaner and with the size of the trans cooler that RR provides you don’t need to use the oem one. I’ve ran my car in 120 degrees with no cooling issues at all. With the external trans cooler you don’t have to worry about it mixing with your coolant anymore. All 3 coolant, trans and oil are separate now.
Edit: This is technically correct but misleading and doesn't really answer kzlflash's question. There is factory oil cooler, it just isn't external.
You'll notice on RR Racing's store page for their oil cooler kit they even reference the OEM oil cooler and how it effects temps... (Note: kzlflash this should also be the info you are looking for.)
15 degree F reduction in oil temps with Factory Oil cooler bypassed (yields approx. 5-8F drop in coolant temps)
30+degree F reduction in oil temperature with Factory Oil cooler retained.
With that said though, calling it an "oil cooler" at all I personally think is a little misleading in itself (though technically correct). It's a very small little doughnut shaped device connected on the side of the oil filter canister, opposite the cap. It is more of a heat exchanger between the oil and coolant... I believe it's primary purpose is to get the fluids up to proper temp faster (likely for emissions?), with the secondary benefit being cooling.
You'll notice on RR Racing's store page for their oil cooler kit they even reference the OEM oil cooler and how it effects temps... (Note: kzlflash this should also be the info you are looking for.)
With that said though, calling it an "oil cooler" I personally think is a little misleading (though technically correct). It's a very small little doughnut shaped device connected on the side of the oil filter canister, opposite the cap. It is more of a heat exchanger between the oil and coolant... I believe it's primary purpose is to get the fluids up to proper temp faster (likely for emissions?), with the secondary benefit being cooling.
If you look at what I wrote I’m very much correct. I stated “external oil cooler” as in exactly what you see on RR racing’s website. The ISF does not have one. The ISF does have a mini transmission cooler and if it had an oil cooler it would have had another mini cooler on the other side for the oil which it does not. Lexus probably saw it as an issue since the RCF and GSF come with an external oil cooler unlike the ISF.
If you look at what I wrote I’m very much correct. I stated “external oil cooler” as in exactly what you see on RR racing’s website. The ISF does not have one. The ISF does have a mini transmission cooler and if it had an oil cooler it would have had another mini cooler on the other side for the oil which it does not. Lexus probably saw it as an issue since the RCF and GSF come with an external oil cooler unlike the ISF.
Ok so maybe you are technically correct if you want to hang your hat on your "external" phrasing. However that still means you misinterpreted and mis-answered kzlflash's question as he never specified an external oil cooler, just a "factory" one... and as per RR's numbers it does in fact make a difference if you remove it or not. We can argue semantics all you want but at the end of the day you are still providing misleading (at best) information.
Ok so maybe you are technically correct if you want to hang your hat on your "external" phrasing. However that still means you misinterpreted and mis-answered kzlflash's question as he never specified an external oil cooler, just a "factory" one... and as per RR's numbers it does in fact make a difference if you remove it or not. We can argue semantics all you want but at the end of the day you are still providing misleading (at best) information.
Yes, knowing misleading misinformation has been pointed out and replaced with correct information that properly answers kzlflash's question is very satisfying. Thanks!
Someone who lives in the desert telling us removing the oil/water heat exchanger didn't make a big difference is also misleading. With no external cooler, and only the water/oil heat exchanger, it takes a full 30 minutes of normal driving in sub 40 degree weather to see 3 bars on the oil temp gauge. Without the warming effect of the water/oil heat exchanger it wouldn't surprise me if it took an hour or more unless you put in a thermostat like they did in the RC F and GS F.
