Advice needed for coolant/radiator issue

[chadsy]

Hey, you guys. I finished installing my rear shocks yesterday and was giving my truck a once over and pulled the radiator cap to check it out and noticed a bit of rust on and around the radiator cap. Also, the PO was nice enough to fill it up on Dex-Cool (Death-Cool) :AK47: which could cause some problems. I would like to remove every trace of this stuff from the radiator and block.

My truck isn't currently overheating or anything but I wanted to get it flushed out before it started getting colder here. Since I'm on a pretty tight budget I can't afford the Toyota coolant so I planned on using Zerex Asian. I have a 96 SR5 4x4 w/ rear heater and I believe it's coolant capacity is something like 12.5 quarts.

Here is where I need your help:

1. Rust around the cap itself would indicate there is some air getting into the system? Would an aftermarket cap do OK? And if so do you have any brand suggestions? Napa?
2. I would like to use a cooling system flush product but I've done some reading that says some of the better options can actually do harm to the radiator itself if there are some thinner spots. Any recommendations here? I would like to get as much rust out of the system as I can.
3. Will I need to remove my thermostat? Or just fill the radiator up with distilled water, run the engine for a bit for the thermostat to open, drain, and repeat a couple of times?

Thanks in advance for the help! And before anyone brings it up I plan on getting a B&M external cooler sometime in the near future

 

[nissanh]

I can get you a used radiator cap (OEM) if you can pay shipping. IF you buy from a store, make sure it says 0.9 and not 1.1. This is the cap's opening pressure.

It is easy to remove the thermostat and do a flush.

Do you have A/T or manual? IF the radiator is old (factory) and you have A/T, it is a good idea to replace the radiator. You can get one from ebay for like $80 shipped.
single row $65: 100 New Quality Radiator 96 97 98 99 00 01 02 Toyota 4Runner 2 7 3 4 L4 V6 | eBay

 

[pluton]

I once stupidly refilled with 'death-cool' on a Landcruiser FJ60. The result was needing to spend more $$ on unclogging the radiator. I'd try to thoroughly get rid of that old coolant.
For my 4Runner, I got an OEM radiator for my V6/MTM for a little over $200. Cheap.
The OEM caps really seem better made than the USA substitutes, and they're not expensive($13?)