Hey guys!

I inherited a 99 4runner limited and man this is a tank, im in love with it so much i am trying to reach 500k miles and currently at nearly 300k well 280k to be exact.

I recently read research and good reviews to do a part vinegar part distilled water flush and run the heater. I did that and i still have milky coolant so ive decided to take the plunge and replace the radiator and yes it is still factory! So my question remains, has anyone done a flush via the thermostat? I havent been able to find any videos on this procedure but i figure i would try it, replace the thermostat as well as the radiator and hoses.

Thanks a bunch and much appreciate any advice, tips, and tricks!

Lf

 

I've changed out my radiator. My advice is...

Only use Toyota Red coolant, mix it yourself 50/50 with distilled water

Learn how to remove the grill before you start. It's a little tricky and delicate. If I recall I used a short- handle flat head screwdriver and need to lift up on the fasteners/clips from behind

Use a Toyota Radiator, yes the KoyoA1998 is ok. I've had both and am glad I have the Toyota in there now

Use new Toyota upper and lower hoses, I used my originals and they started to leak at the connection. A new hose fixed it not a new clamp. The new hoses were tighter than the old original ones

Make sure to get all the air out, It helps to elevate the front and go through a couple warm then cool cycles, using the heater. After the initial fill, I top off though the overflow reservoir letting the radiator suck it in and do not open the rad cap. Watch the level in the overflow after driving a few times to make sure it doesn't drop as any residual air in the system is purged

Might as well use a new Toyota rad cap. I have had them fail.


It's a rewarding job, good luck.

I hope to get mine to 280,000.

 

I was also looking at the denso, seems to have good reviews. Plan on changing hoses, radiator cap, etc.

I live in texas, is using toyo red really necessary? Ive heard both ways are fine as long as you stick with one and dont mix the two.

Im looking to flush via thermostat to ensure complete flush, have you done so?

 

Didn't do a flush per se but did a couple drain and fills.

Toyota Red has worked well for me. But that's what's been in mine since I got it so it was easy to stick with the Red.

I bought the Denso off Amazon and it came with a broken overflow nipple due to poor packaging, I returned it for the Toyota radiator. One difference was the Toyota had rubber mounting bushings and the Denso had plastic.

 

Taking off the grill helps, but in my opinion isn't worth it. Like he said, it's tricky and delicate. Maybe it's different with an auto tranny? I don't know. I got my old radiator out and new one in no problem with the grill on. You just need an extension on your wrench and go in at an angle. Slightly "tricky" but in a completely different way, with no chance of breaking old, brittle plastic attachments on the grill.

It's not necessary to use Toyota Red. Like badattitude, though, I definitely use it. I figure why not? It's pricey, but you don't need to replace it again for probably the life of your 4Runner.

I don't know anything about the flushing. I know they make kits with chemicals to use.

So you're talking about putting a hose in where the thermostat goes and forcing water through there? I don't know. I replaced my radiator & cap, hoses and thermostat not too long ago and wished I had flushed it at the time also, but oh well. I don't have any advice there.

 

Never heard of flushing VIA Thermostat nor is it possible, a flush is performed using proper chemicals, all my 4runners have green or universal yellow rad fluid, aftermarket lower rad hose(upper never fails) radiators and rad caps, no problems, 1 motor has over 460,000km's. Toyota stuff is good but they don't make rad fluid, rubber hoses or radiators so mOsT of the generic aftermarket OEM equivalent stuff will work fine. I found on the 99Ltd is was much easier to remove the grill to get the rad out, the 97 SR5 it wasn't nessessary. I'm not sure where all the hype over "toyota" Red rad fluid came from, probably when the 96 head gaskets failed, it is advised to completely flush out the flush chemicals and other coloured rad fluid before switching to another colour which takes 3 fills and drains to get all the old colour out. Rad fluid stops corrosion of metal parts, lubes water pump, stops freezing/boiling and cools the engine so Red, Green or yellow fluid won't make any difference in my experience just use a brand name of some type and distilled water.

 

Ive done 2 flushes with proper rad chems. It maybe due to original rad being bad. so while i have rad pulled and thermo i figured id do an entire engine flush until water comes out clear through the thermostat.

 

it doesn't work like that, you don't pour fluid in your rad and watch it pour out the thermostat housing to flush it, it won't pump coolant to all the little hoses and both heater cores so you will and up with chemicals in the new rad fluid, to get the chemicals out you will have to fill it up with water and run it till it reaches operating temp and the thermostat opens and allows the clean water to flush out the chemicals you put in to clean the system, as mentioned you will have to do this 3 times if you want to change colours and I would do it twice if I ran flush chemicals in there. Lets hope the original rad didn't fail, if so I would be more concerned with a transmission flush.

 

Sorry my last message was not clear. I meant pulling lower rad hose, sticking hose in thermostat, and flushing through engine letting drain via lower engine. This works correct?

 

Nope, that won't work either and is a complete waste of time and goes against all logic. If you read what I wrote it may become more clear as to why creating a stream of water will not flush out the entire system and is ridiculous. Heater cores, throttle body, rad hoses, upper block, or even the top half of the rad will not be "flushed" of the chemicals… I'm sure there is videos on this and I'm sure you will find nobody pouring water into the rad and watching it run out the T-stat or lower rad hose, or attempting to pump water in the T-stat housing.. please step away from the truck and put the wrench down.

 

What a dick. This was a suggestion from a mechanic btw.

 

Ya sounds like he was pulling your leg, very common in this industry, like check your muffler bearings or get me the air brake fluid