Help with getting Coolant Level Right

Just fill it up.

 

@GilbertOz I would wager yes that would work. Risk using tap water is the hardness/PH/mineral content is unknown (Or in my case known to be terrible). 5 or so Gallons of distilled after a hose flush should be fine (Would I do it on a German car? Hell no, but Toyota yes). What little tap water is less should be "Buffered" by the sacrificial anodes in the fresh coolant.

Make sure you have the heater on full blast iot to circulate your flush thru the heater core

Also, use the block drains, easier than you think once you find them, on my 3.5 I got more to drain out of the block drains than the petcock

 

Thanks, yes, got tipped about the block drains in some YouTube video or other, surprised they aren't mentioned more often. I also plan to use one of those

$55 Lisle 60800 Heater Core Backflush Tool with Air

air-compressor-to-hose-sprayer adapters that injects air blasts & bubbles into the flow stream to help loosen up deposits. Of course starting w/ conservatively low air-PSI regulator settings like 30-40 PSI, working up the PSI setting gradually, subject to my judgment. This tool is described as a "heater core backflush" aid, but some people apparently also have good results using attached directly to the end of a disconnected radiator hose.

I will probably use hot tap water, from the water heater, of course after I do a thorough flush of the house's hot water heater to get it clean & clear of any sediment.

Really interested to get as much crud out of the cooling system as I can on my 2014 Taco w/ 68K young miles on it. Coolant in reservoir is still a nice pink color, but there are no records of it having ever been changed. (I'm 2nd owner, bought it at ~61K miles.)

For this first change I bit the bullet and bought the $37/gallon Toyota SLLC2 pink 50/50 pre-mixed coolant. I am highly suspicious that this may be just rebranded and marked-up pink Zerex™. Maybe some deep dives into the SDS's for these products will help me figure out if Zerex is good enough for next time. Plan to start changing coolant every 30-40K miles or 3 years going forward.

 

Looks like a great plan! You'll probably sleep better also, mitigating risk and knowing the job was done correctly

 

I did the coolant flush, 2nd gen V6 4.0 / 1GRFE. ~2.05 gallons came out, 2.05 of Toyota SLLC2 50/50 pink pre-mix went back in. I am not certain but I think the old coolant had the truck's full 68K miles on it. I was amazed how good it looked -- almost as clear as brand new coolant. Or, maybe the coolant was changed previously but wasn't in the full paper service history I got w/ the vehicle when I bought it.

But after the flush, I immediately noticed two things:
- Heater blows far hotter, so hot I can't hold my hand up to the vent for longer than 5-7 seconds.
- Seems crazy, but the butt dyno seemed to feel an easy 5-6% increase in engine power. I don't have any before/after data on oil or coolant temps, having only the stock temp gauge, and no OBD-II before/after data, so I can't quantify this. My theory is that the new coolant simply cools a lot better & keeps cylinder temps lower, allowing increased power output. Efficiency of a heat engine increases as the average temperature delta between intake & exhaust increases. I am looking forward to seeing whether this improvement shows up in my mileage-tracking over coming months.

New/used coolant comparison:






Some take-aways:

- Opening the block drains is a must do for a coolant flush, at least on any vehicle that is young enough that the drain bolts have a high chance of opening normally, rather than being seized. Over 60% of the used coolant came out of the block drains, not thru the radiator.

Here's a video someone else made showing how to access the block-drain bolts:

https://www.youtube.com/watch?v=U08U9Vk7N7g

- Block drain nuts are 10mm. Torque spec for this nut is 9 lb-ft on the 1GR-FE engine but due to the angles involved I didn't use a torque wrench. 9 lb-ft is "some, but not a lot," or "about as tight as needed for a 10mm bolt going into aluminum threads." NB for less-experienced people: if you aren't confident that you can work these bolts without damaging them, probably best to leave well enough alone. They do not have to be fully removed for the drains to open fully, so don't take them all the way out. W/ the driver's side in particular, if using a mega-long stack of ratchet extensions +2 separate elbows, you want to control your torqueing very carefully. (Some people on youtube claim to be able to get their fist up in the engine bay from underneath & just use simple 3" straight extension. Maybe I'll try that next time if I lift the truck for the work.)

When closing them, they should be, you know -- just ratchet-snug. No ugga-duggas! I closed mine with minimal torque until they stopped, and then went maybe 1/8th of a turn beyond that.

Stripping the threads on a block drain would be a PITA to fix. Seized threads more likely to be an issue w/ high-mileage engines. (I'll see how my 185K '99 Tacoma 2RZ-FE 2.4L fares with block-drain opening in a week or two.)

- I managed the block drains by using an absurdly-long 40" stack of extensions & elbows. See photos. Note, the passenger side is pretty easy to get to and can use a straight socket at the end of the stack. The driver's side needed wheels turned full left, and an additional swivel right at the tip of the stack. Took so long to get the socket on the drain nut that once on it & loosened, I carefully left the whole stack attached to the nut so I wouldn't have to re-locate the socket on the nut again when closing the drain.






- Did not lift or even jack up the truck. Too lazy to take off the stock skid plate, so I wasted a lot of time & hand-strength working the radiator petcock open & closed.

- Using hot water heater to supply hot water for an intensive flush didn't work. Even after flushing my 40-gallon household hot water heater with 200 gallons of water, there was still residual scale coming out.

- Instead I used cold garden hose water to flush the radiator, under pressure. (Using a rubber seal ring between hose & radiator.) Also used the "air injection" function of the Lisle™ tool I linked in an earlier post. I watched / squeezed the radiator upper hose to monitor system pressure & avoid blowing out any coolant-system components. (Ideally the best way to do this would be to have a water pressure gauge in-line. Average home tap water supply static pressure is 50-75 PSI, which is probably easily enough to blow out radiator hoses if allowed to build to that level.)

- Flushed radiator w/ tap water for ~5 gallons, which takes quite a long time when going thru the petcock at bottom, even under pressure. Then closed radiator petcock & opened block drains, and repeated the same pressurized-cold-tap-water flush.

- Opened all petcocks, allowed all to drain, then refilled & flushed with bottled distilled water, about another 5 gallons, this time using a standard

$21 EPAuto Spill Proof Radiator Coolant Filling Funnel Kit

lock-on/spill-proof radiator funnel. Interestingly, with all 3 petcocks open, some distilled water still ran out of the block drains simultaneously. I closed the radiator petcock half way through to ensure that plenty of distilled water would flush directly thru the engine block.

- Re-opened radiator petcock, let everything drain out, then closed all 3 drain ports & used a venturi/vacuum coolant-refiller tool to suck in ~1.75 gallons of new coolant. Even w/ the vac tool there was still some air to burp out of the upper rad. hose, and I added another ~0.3 gallons thru a plain funnel to top it up.

- Ran the engine at idle for 10 mins to come to full temp, w/ rad. funnel still on, watching for any more level changes, carefully squeezing upper radiator hose to burp it. No coolant level changes noted in fill funnel. No unexpected fluctuations on engine temperature gauge. (Helps to have a translucent fill funnel so you can watch the coolant level while sitting in the driver's seat.)

- Closed up radiator, waited overnight, re-checked radiator fill level next day, then went for a long test drive, carefully for first 15 minutes, then aggressive long WOT pulls. Temp gauge stayed stable throughout.

- Completely forgot to flush the heater core. Whoops. Oh well. That probably explains why only ~8.05 quarts drained out of the system instead of the factory-specified ~10 quarts. Per earlier posts in this thread, Toyota Pink is fine being mixed with quart or two of in-engine/pre-diluted Toyota Red without any issues.

 

Is that coolant crust at the seam? Is the cap leaking down onto it?



A new radiator might not be a bad idea anyway. It's 20 years old ..

 

Replacing the radiator soon (

$168 Denso 221-3138 Radiator

Denso 221-3138), gates upper and lower hose, thermostat and radiator cap. Using Peak Asian Pink, 1 jug of concentrate and 1 jug of 50/50. I mostly have read that when refilling after a flush, one should use only concentrate. Well, I'm going to use my recipe. BTW, I have a used Harrison OEM radiator with a hairline crack in the top plastic. Any suggestions as to what can be done with that beside recycling? Maybe a swamp cooler?