I have a 2011 RDX with pretty low miles and was installing a Magnefine filter yesterday and contemplated bypassing the built-in transmission cooler that's in the radiator. I see the radiator failure (coolant mixing with transmission fluid) is a pretty common problem in other Acura & Honda models & years.
I haven't heard of it happening specifically in the '10-'12 RDX models yet, but I did see some instances of it occurring in the '07-'09 RDX.
I did a little more research and from what I can tell the original radiator part # for the '07-'09's was 19010-RWC-A51. That part # is no longer available and it has been replaced with radiator part # 19010-RWC-A52.
Now, it appears as if the '10-'12's did come with the "updated" radiator from the factory (19010-RWC-A52), but of course I still have my doubts since the problem seems to be so widespread amongst other models and years.
I'd be interested to know if anyone has 1st hand knowledge of the radiators failing in the '10-'12 RDX model years? This way I can then weigh my options as to how I want to proceed.
Thanks.

 

most OEM radiators are built with aluminium and plastic. guess what breaks? yep, the plastic.

over the years, the plastic gets brittle from heat! and it's the most common failure point on almost all OEM radiators.

 

Dont guess, measure the stray voltage, apparently a large factor in such instances (dissimilar washer material and electrolysis).
Msg #19
https://acurazine.com/forums/1g-rdx-...tumped-961393/

Also inspect the hookups for any sign of rust on ALL SIDES, use a smartphone for inaccessible angles. Remember the corrosion starts from inside, not visible for many years.

I have done the bypass on my base-2008, after considering the worst failure case scenario with and without the bypass. I do not recommend the bypass if you are doing a lot of idling or stop and go traffic: seems transmission fluid accumulates more heat in these conditions, due to low flow in first place ie. higher temperature level than the coolant. If that does not apply to you, it's a good, easy and free mod, reversible in 10'.

I have switched to doing yearly dìstilled water refills followed by fresh coolant, despite having the bypass in place.

hth

 

I still believe a significant contributing factor to failing radiators are people not sticking to fluid change intervals, especially those that maybe don't drive a lot and therefore don't think about fluids that degrade over time regardless of miles driven. Old coolant becomes corrosive and can easily eat the radiator from the inside out. Some are defective, sure, but I would put money on there being a link between radiator failures and people with 5-10 year old coolant sitting in their cars.