I guess it's been known to be an issue with the RX: I can't see the crack but the hoses are dry and it's leaking out the bottom. So I'm going to try and replace it myself: this is the first car I've ever worked on, and so far I've done the serpintine belt and pullys, replaced the rear struts and taken out a leaky headlight more times than I'd like to mention.

But this seems...doable. Wondering if anyone has any tips...and also what (if anything) I should replace while I'm in there. She's a 2008 with 82K.

 

For sure, get a alloy radiator.....I'd replace the upper/lower hoses as well & use the oem style clamps vs the worm clamps.

 

I replaced the A/C condenser on my Rx350, which pretty much is same as replacing the radiator, it it was a DIY job for a shade tree mechanic, so go for it!

 

If the radiator is coming out, best to flush out all the coolant and change the T-stat (OEM ONLY!) and all hoses or at least the big hoses.

I'd suggest OEM radiators in this case, pricey but you know it will work. I bought a cheaper aftermarket for my old camry (it was on its last legs anyways) when the OEM cracked and the OEM fan didn't fit....... took some rigging and ghetto'ing to make it fit since there was no way I was or could return it.

Also have some fresh ATF fluid as you will lose some disconnecting the transmission cooler hoses.

 

I appreciate the tips! I have no choice but to go OEM: mine is made in Japan and requires a special fit. My choices are Lexus.com for $400 or Lexuspartsnow.com for $300...

But at least I’ll know it’ll fit!

 

You do not need an $400 oem thermostat buy an ac delco one for like $20 make sure you place the jiggle valve at the 11:45 position. There is no mechanical difference between the NAP or JAP produced RX330 so a thermostat that works in the NAP one will work in the JAP one.

Also you do not need an oem radiator here is one for $123
https://www.amazon.com/Radiator-Pacific-WITHOUT-ALUMINUM-VERSION/dp/B01MSYHA93/ref=mp_s_a_1_4?dchild=1&keywords=rx330+radiator&qid=1587024901&sr=8-4

There is no point in spending hundreds of dollars more on something for a over 10 year old car because it says Lexus/Toyota on it. Take your pic of thermostats below AC delco produces oem GM parts I replaced my thermostat with an ac delco one and it works 100x better than the old oem one.

https://www.rockauto.com/en/catalog/lexus,2004,rx330,3.3l+v6,1421312,cooling+system,thermostat,2200