To Flush or not to Flush that is the Question

im coming up on 100k miles and im due for some new coolant, would it be a wise move to flush the system with distilled water then refill with my Toyota SLLC coolant, or just drain the block and radiator and refill the engine. Im using the Toyota oem coolant so there is no possibility of cross contamination from a aftermarket antifreeze.

 

I do think it would be wise to flush, I don't believe there's a down side to it

 

if it yellow let it settle if it’s brown flush it down!

 

supposedly there would be distilled water left in the heater core that would get left behind,and not make a 50:50 mix?? what read somewhere

 

no its the original coolant still very pink, I was just thinking to run 2 gallons of distilled water thru the radiator/block with the petcocks open and let it drain without running the engine, that way I don't mess with the little coolant in the heater core and hopefully flush some residue(if any) out of the radiator.

 

The heater core isn't very large, that wouldn't be much. Hook a vacuum up to the hose and suck it out lol

 

You are doing this coolant service at the prescribed interval and there is no need to flush the system. If I recall, the service manual does not say to flush the system. Toyota SLLC is very high quality and designed to keep the system clean and free of scale, rust, etc. A flush is a usually good idea for vehicles using regular green coolant (ethylene glycol), but I don't think you should not add any water to your cooling system for any reason.

 

I would, but if you don't - it's NOT going to kill the motor or heater exchange. I changed mine when I hit 130,000 and it smelled and tasted sweet.

Okay, so as above - you can taste and spit your coolant. DO NOT DRINK IT. Call it old school but rule of thumb goes if it taste sweet, its good. If its bitter - it's gone.

 

if its still pink let go have 233000 on my 2012 never been changed

 

this is also what I was assuming, since I never used any aftermarket coolant and sticking with the OEM stuff just drain and refill at 100k miles, although ive read where others that use a aftermarket Toyota Asian equivalent coolant do recommend a flush because the formulas are not completely alike and may(probably unlikely but who really knows) cause chemical imbalances .

 

I have read of many people using the "Asian" (LOL) generic coolants where SLLC is prescribed, usually without any issues. I prefer to spend a few extra bucks every 50k miles and use the premium stuff. Oh bytheway, the first coolant change is at 100k but all subsequent cooling system service is every 50k. Just wanted to be sure you knew.

 

jup im going OEM coolant, with every 50k miles after. I got 2 gallons of SLLC OEM Coolant from EBAY for $40 shipped best price I could find, also noticed the Prestone offers an ASIAN only formula at Walmart

 

If the system is clean and has never been contaminated, I see no good reason to flush it with water before refilling it.

And while we are on the topic of anti-freeze:

Unless diluted, anti-freeze maintains its anti-freeze properties FOREVER. It's only the anti-corrosion properties that degrade over time.
Back in the day, when we had a good system that was clean and didn't leak, we would just drain about a quart of coolant out and add a bottle of water pump lube/rust inhibitor about once a year. That coolant would stay in the system until something failed, usually a water pump, or there was damage to the system (like a deer through the radiator !). Without some type of failure that coolant would stay in there for the life of the car.

 

When I replaced the plastic coolant pipe with the newer stainless one, I used the OEM stuff. I found a local auto parts store that sold it $10-$15 cheeper than my local Toyota dealer was selling if for.

 

jup, its safe to stay with what the manual states then there wont be any chemical reactions that could c ause gelling. my brother has found that out the hard way he has a Chevy s10 v6 that takes DEXCOOL and he either introduced another type of coolant or water into his system, he is now on his 3rd radiator and water pump because once he introduced the wrong antifreeze into that system it needs to be completely flushed because it gells up over and over because some of that wrong coolant remains in the system and causes mayhem. at this very moment he is putting in a new water and Chinese spectre radiator I hope he has learned his lessen and use the proper DEXCOOL this time.

 

jup, its safe to stay with what the manual states then there wont be any chemical reactions that could cause gelling. my brother has found that out the hard way he has a Chevy s10 v6 that takes DEXCOOL and he either introduced another type of coolant or water into his system, he is now on his 3rd radiator and water pump because once he introduced the wrong antifreeze into that system it needs to be completely flushed because it gells up over and over because some of that wrong coolant remains in the system and causes mayhem. at this very moment he is putting in a new waterpump and Chinese spectre radiator I hope he has learned his lessen and use the proper DEXCOOL this time.

 

Dex-cool is a great product, but like your story says, it must NEVER be mixed with any other type of coolant or chemical. The results are often catastrophic and it's just not worth the risk. But there are many stories of people who kept using it in their GM vehicles and decades later the cooling system is sparking clean.

 

my brother is out in the 95 degree heat putting in all the new radiator,water pump and he said he flushed the system and the heater core was jammed with gelled coolant, he said that he will be using PEAK global lifetime brand antifreeze that was rec'd by a few websites for use in GM dexcool vehicles, he said that on the bottle its safe for use in GM dexcool vehicles, I hope he is right.

 

Everyone, keep in mine the "recommended" changes are at an extreme. It sells trucks that services are at long intervals, NOT what is proper. All of the extended fluid changes are for promotional reasons, not for what is good for your engine. I have learned the hard way that doing things the "backyard mechanic" way usually do not work. If you need/want to change the coolant, you first need to flush (clean) the ENTIRE coolant system, heater core and all. If you want to do it yourself, drain out everything you can. Put in plain water WITH A GOOD CLEANER and run it for a few DAYS. Then flush it out and do it again with plain water for the same time. Only after this, drain out the plain water, add your antifreeze and any additives (I do), and relax. DO NOT SEEK AN EASY WAY OUT!