My AP2 is at 164000 miles. I know Koyo is popular option. I know it also needs a new different radiator cap. Does anyone have the part numbers needed? Also, what is the part number for the fluid needed? My local parts department only has the blue fluid. I assume the correct one is red. I am also looking any alternative direct drop in options. I appreciate any advice. Thanks!

 

Any s/hand rads near you ?

 

I'm not sure what those are. Please explain. Thank you.

 

A second hand used replacement of another car ,ebay ect.

 

Honda coolant is blue, Denso radiator:

https://www.rockauto.com/en/moreinfo...pt=2172&jsn=13

 

Koyo Rad is part number: VH081226
Another good option is CSF Racing, Part number is: 7009

Koyo rad cap part number is: SK-C13

OEM Honda type 2 coolant part number is: OL999-9011 (it is blue, all Hondas except a few EV models use this coolant and it is always blue) NEVER RED

 

I just did the Koyo rad. So far so good!

 

Never get a used radiator unless its full aluminum. OEM used radiators are no good, plastic dry rots.

 

Note that Honda coolant is premixed. No need to add water. If you do add any water, make sure its distilled water, not garden hose.

If the stuff in there now is red, suggest a full flush, to avoid compatibility issues. Get several gallons of distilled water from grocery store or Walmart. NOT spring water. Distilled water like for clothing iron.

Fully drain, fill w just water. Run until heater blows hot. Fully drain. Now fill up with Honda blue.

Use a Lisle type funnel, park nose up, use the air bleeder valve, make sure heater blows finger burning hot. With funnel still in place, rev engine a few times, then hold it at like 3k rpm for 30 secs. Twice.

These engines notorious for difficulty bleeding all air, and all can seem fine, then one day it overheats out of nowhere, and fast enough to take out engine before you realize what is happening. So not something to take lightly. Make sure all air is out.

If you're concerned about the rice look under hood with polished radiator, here is an option:
Koyo painted Black

 

+1 w/JBamin, Car Analogy. I now have a 2004 AP2. I needed to replace the radiator and cap after a mechanic checked it, and the cap spring fell into the radiator. Not the mechanic's fault, parts fail after so many miles. I have about double the miles you have. Anyway, they were honest and told me. I ended up replacing the radiator and cap. I am using a cap from Oreilly's (Murry's P/N: 7037, alternate is 7737 and both are 16PSI) and it is still working with the radiator. I picked up the radiator at local Performance Radiator in the PNW. (p/n: 2720) FYI, I tried using another blue Japanese car coolant and it just needed to be added more often than usual. I recommend using Honda genuine coolant as you should not have to top it off nearly as much. Lastly, use the Billman bleed method. I did, and have not had an issue so far.