what do you guys think about this my cap is pretty old.
https://www.lexussouthatlantaparts.c...040000003.html

 

Pure water boils at 260F under 16lb of pressure. 16 is the OE rad cap rating. Adding coolant to the water mix increases the boiling point as well. A street-driven LS doesn't need an 18 lb rad cap.
I'm sure they look nice in the Lexus and Toyota parts stores next to the golf shirts...

 

100% agree. With elevated pressure, you will also increase your risk of coolant leaks due to failures of aging hoses, radiator, heater core, etc. The radiator gap is a pressure-relief valve designed precisely to minimize such risks.

 

Depending upon your use, perhaps a "tow package" radiator would make more sense.

If at or near 175,000 miles is when radiators reach end of life... On the LS400 side this seems the case with plastic top/bottom tanks and rubber sealing rings.

Additional system pressure may not be the answer.

 

If you decide on more system pressure be sure the rest of your set up is good to go so nothing seal wise cracks or breaks or has issues. Even if you are using a stock engine there are benefits to a higher pressure cap because they reduce the likelihood of flash boiling in certain areas of the heads which is a known issue for some engines that I sincerely doubt is an issue the 3uz has.

However technically speaking if there's nothing else wrong with your cooling system and you're confident in the seals and the radiator tanks there should be no issue with going to the higher pressure cap because it will simply make it harder for flash vaporization to occur at any point inside the cooling system. Operating temp will not change and it will be more accurate throughout the loop in situations you are pushing the car hard like say a 150mph run or if you regularly thrash it

If your radiator is marginal this is a great way to figure out if you need to replace it

 

Definitely will avoid it thanks for the informative responses

 

I would think the reason for that cap is the logo, and our caps are not visible, so I wouldn't spend the money if it were me.

Is the factory cap made in Japan? For my wife's GM, a faulty original cap caused coolant to be unable to return to the reservoir. I changed the water pump Labor Day 2019, and so I watched the coolant level 2X or more per day, wanting to make sure no leaks. One day, coolant at FULL cold. Coolant above FULL hot. Next morning, coolant above FULL cold (at the hot level). I was baffled. Turned out to be the cap. So I bought both the Gates and the AC Delco OE cap. Both were made in India, and the Gates somehow seemed better, so I used the Gates. I would have preferred the AC Delco because its labeling was identical to the original. But, like the LS430, one can't see the cap it's under plastic shrouding.