Thanks for the responses guys, so if I'm understanding this correctly... if you live in an area that does get pretty cold from time to time (like Socal where I live) and you buy the RR racing oil cooler kit, then you should NOT bypass the factory heat exchanger (i.e. the donut) so that you retain the warming effects that the OEM heat exchanger provides, which will ensure that your oil temps are warmed to a sufficient level at a quick enough manner?

 

You do know the Setrab coolers RR racing provides comes with a thermostat in it right? Clearly you don’t so I’ll school you up on it. It’s a Mocal 185F thermostatic sandwich plate. Since you clearly don’t live in the desert idk how you can try and provide any real world advice and tell anyone who lived in the the lower desert which would see 125 degrees and try to compare warm up temps in 40 degrees and 115-125 degrees. People who have the oil and trans cooler running at willow springs and chuckwalla don’t have the same issues people who don’t run them have. Talking about a car warming up from a cold start in 40 degree weather VS me talking about running the car hard during track or racing are two totally different things.

 

Call RR racing and ask them since the people talking about the koyo radiator, trans cooler and oil cooler don’t even have one on there car. I actually do and never had any issues warning up, any over heating and my car warmed up normally.

 

OK, and I've been to the track at 102F with an average speed of ~68 mph and had zero issues with overheating anything with no additional cooling. So we both have experience in our environments. Lexus's oil cooler in the RC F and GS F doesn't open the valve until over 100C.The biggest issue with warm up is fuel dilution. These engines are tuned rich from the factory to avoid warranty claims from running lean. So they puke a lot more fuel into the oil than they would with a tight tune. This means the oil has to get hot quickly or suffer degradation from viscosity loss. This means zero at the track. It means everything for a daily driver who wants to avoid rebuilding an engine as long as possible. Saying "well, I never had a problem" doesn't mean a lot other than you've not experienced a catastrophic failure. Most won't. There are LOTS of things people on this forum do that don't immediately impact the serviceability of the vehicle, but they definitely impact the service life of the vehicle and definitely impact maintenance intervals.

Keeping the OEM heat exchanger will warm the engine faster, and that's important for street duty and oil service life. That 185F thermostat is great for a track driven vehicle. It's not great for a street driven vehicle and that's why Lexus's thermostat opens between 100C and 120C. There's plenty of race car stuff out there that works great on the track, but sucks acorns for street duty. Reality is, if you never intend to track the car, you'll never see oil temps or coolant temps high enough to warrant additional cooling. You might want an aluminum radiator so you don't have the cracking issues the plastic tank units have, but saying it's inherently better and you only have to redesign the OE cooling system to make it work isn't fair for someone who doesn't plan to do hot laps in the car.

 

The aluminum radiator I will agree is better and worth the upgrade since you won’t have to worry about it leaking or ever needing to change it. Mine leaked and I decided to go all aluminum instead. As far as everything else you mentioned I do oil analysis during every oil change. So far all my wear markers, metals, etc in my oil look great. Only reason I say I’ve had no problems otherwise I would have no idea what’s going on inside. I’ve had my car for 4 years now and did everything within the first 3 months so it’s not like it’s only been a few weeks or months. Bought it with 84k and I’m currently at 140k.

 

So according to RR, if you buy their kit and retain (use) the OEM heat exchanger you'll get greater oil cooling functionality compared to bypassing the OEM exchanger. And according to Lobuxracer it's also in your favor to continue using the heat exchanger for DD/street driving. So it sounds like NOT bypassing is the way to go then since you get the best of both worlds.

Maybe I'm being dense then, but what's the point of bypassing the OEM exchanger, just for the slightly cooler coolant temps?

 

ISFpowered please help! What are these weird things on my car!?!? Should I part out!?!?!?



Maybe you should realize you know nothing about me or my car before posting stupid blanket statements.

 

Which one(s) do you mean? Coolant? Engine oil? Transmission oil?

If you go with the aluminum coolant radiator, you have no choice but to make the transmission cooler larger. The unfortunate part is you lose the stabilization effect of the copper tube in the radiator lower tank. It makes sure the oil heats up quickly, then when the oil is hotter than the coolant, it transfers heat to the coolant radiator. The aluminum radiator option does not do this, so you'll have more variability in the transmission oil temperature. What that ultimately means to the operation and longevity of the transmission is unknown. Might make no difference at all, might make it shorter service life, but under track conditions it will most likely extend service life.

One of the great misconceptions junior tuners have is cooler is better. It's just not true. There is a target temperature for all your fluids, and the goal is to have them at that target temperature as much as possible under the driving conditions you normally experience. That's why we have thermostats for coolant and oil, and why you shouldn't beat on your ride until the fluids are at normal operating temperature. Sadly many guys think engines run better when they're cooler. It just isn't so. There's a thermal balance you need to find - cool just enough to avoid detonation, but not enough that the next cycle loses more heat than necessary to the cooling process. Any heat your cooling system sheds is lost energy, and the more energy you can focus on moving the piston the better. Same is true for exhaust. The ideal (adiabatic) engine would have a cold exhaust because all the heat generated by combustion would be used to move the piston (and not to add heat to all the parts surrounding the piston,) We'll likely never get there, but many have been close for very brief periods.

So all the stuff about additional cooling capacity is really for those people who are experiencing problems with cooling. They're pretty exclusively running at the track with a duty cycle far beyond the design spec for our street oriented platform.

FWIW, I have NEVER in 13 years and 180k miles of operation seen my oil temperature higher than 3 bars EXCEPT at the track where it was clear the car needed additional cooling for how hard I was pushing it. I also found as I was able to better manage the car and bring up my average lap speed, the cooling issues got smaller. Still there, but a lot less problematic - not seeing 275F oil temps again, more like 5 to 6 bars instead of 7.

 

Anyone know if the radiator with part number 16400-38211 fit/work on my 2010 with no issues?

 

^^^ From what I understand you need the below as its a kit for a reason

If my radiator where to blow out again, in theory I now have the newer hoses and coolant bottle, so then the 16400-38211 should work as just the radiator replacement alone.

 

What's the average life on these radiators anyhow? This will be the third replacement for mine soon as the top of mine is leaking. Based on the service records, mine was replaced back in 2012 at 50,570 miles due to the fans melting onto the radiator. I'm now at a little over 154K miles.

 

Typically when Toyota/Lexus has a part number with an H in it, it is a replacement "kit," that is, the part updates the original to the newer specification, that is also what happened here. I am not sure when/why Toyota does this vs a multi-number supersession, but they do.

16400-38H10 includes the following parts:

16400-38211 - Radiator
16470-38041 - Tank, Reserve
96136-42101 - Clamp, Reserve Tank Hose

16470-38041 itself contains the following updated part:
16567-38031 - Hose, Reserve Tank

After replacing the radiator on a 2008-2011 (up to March, 2011 production) with 16400-38H10, any future replacement parts can be ordered from the later vehicle instead (ordering the earlier parts would not fit).

Jeff

 

this explains it. So when you order a radiator for a 2012 car from Lexus, you only get the radiator and nothing else, since all other updates had already been applied at the factory by the time the car was built.

 

My radiator currently looks tasty right now

 

@xdejablu3x if it's not the small outlet neck cracked that goes to the reservoir hose.. Then for sure the top seal / gasket blew just like mine...

What are you other MODS if any?

My original 08 went out on me at 100k miles ish

Joe Z