coolant system flush while replacing radiator

ok iv searched all over and cant find anyone addressing this concern, im replacing my radiator and want to do a coolant system flush, block, heater core and all. but im curious do i do the flush with the old radiator on or with the new one on. or is there a way to do a flush with no radiator on?

 

I have to flush mine soon..

 

You need to drain the coolant out to replace the radiator anyways, so why do you think you need to flush it too? The little bit of coolant left in the engine won't hurt anything.

 

I would flush it just to get the passage ways in the block and hoses clean too since you are there already. OP, I dont think there is a specific order you need to do this. Personally Ide do it with the old radiator in there. And Im sure you cant flush it with the radiator off.

 

Anyone should flush a system if replacing a radiator if they like to do good jobs not half ass. Unless the truck has low low miles and even than I'd still do it.
I absolutely have to do it because I was topping off with green coolant and didn't realize the effects of that. So I am going back to silicate free Toyota red coolant and I want it to be free of all the nasty old coolant.

 

I worry about flushing out nasty rust or deposites from the old rad into the engine block. But than again I don't want to flush nasty engine block build up into my new rad.

 

I would do steps 1-7 first with old radiator then replace it and do it again after new radiator is installed.
Coolant flush steps
1. drain radiator
2. disconnect upper radiator hose
3. put garden hose into radiator fill
4. turn on water & start engine
5. run till water is clear then shut off water
6. when engine stops pumping water out hose shut off engine
7. reconnect radiator hose
8. add coolant till radiator is full
9. start engine & add coolant till it wont take any more
10. let engine get warm then let it cool off & check coolant level

 

I was considering the 2nd being more of a problem, having crap from the block going into the new rad. I think you'de be fine giving it a good flush with the old rad on, do it twice if it makes you feel better. Or as many times as it takes until you are draining clear fluid out of it. Are you going to be using a chemical or just distilled water?

 

I'm going to use the garden hose then 1 gallon of distilled water.

 

Bunp

 

Flush the system with old radiator on, till you get clean water, will take several times, then for good measure flush the system once or twice with the new radiator on, to clean out any materials that were left from manufacturing. Then add your 50/50 mixture. I used regular tap water to flush coolant system.

 

Which radiator hose is the output to the engine? Upper or lower? Should I flush with both the drain plugs open? Iv read to run the engine while flowing water from a hose in through the radiator cap until its warmed up so that the thermostat is open. If I have the upper rad hose is disconnected is it ok to have that water dumping all over the radiator? I'm sure it will be ok but is there a better way like just having the lower drains open?

 

Whatever you do, refill your cooling system with toyota long life coolant don't use the new super long life coolant. Im a mechanic at Lexus and that stuff causes nothing but problems. When I get my 2012 thats one of the first things I'm draining out of it. We never had issues with cooling systems like we do now. Just my 2 cents.

 

I havnt done a flush on my truck but I have flushed my bikes many times, I drain the old coolant, fill the system up with cleansing chemical,(CLR works great from what Ive heard, never tried it, might want to check it out) seal up the entire system and just run the engine until the water starts flowing, let the system circulate for a few minutes, flush then repeat. Its easier on bikes because they heat up quick but that is how I plan to flush my system on the truck as well.

 

Whats the problems you guys are having? I am assuming this coolant is ordered through the dealer? When I do go to get this coolant, I just ask for "long life coolant"? Does the other one actually say "super long life coolant" vs "long life coolant"?

 

Bottom hose is output of radiator, top hose is output from engine. I rinse everything real good when done and haven't had any problems.

I never open the drain plugs (crap can get in them and cause them to leak).

Yes and turn the heater to full hot (so it gets rinsed also).

I rinse everything real good when done and haven't had any problems.

 

Doesn't coolant flow through the heater core regardless of the heater control positions in the cab? I thought the levers simply controlled whether air is routed across the core?

 

I don't know it's just the way my father taught me a long, long time ago in a galaxy far, far away.

 

I would think the temp selector lets the heater core open up and the fan selector allows air to flow over

 

Based on the attached extract from the FSM, I don't think so. I believe the temp selector controls the "percentage" of air flow routed across the heater core (note the AIR MIX terminology), while the fan selector controls the total flow of air through the system.