Is a coolant change really this hard?

1996 3.4L V6

I bought 3 gallons of Toyota coolant, new radiator hoses and clamps, a length of smaller silicone water hoses to replace around the throttle body, and am watching DIY videos again to prepare.

The guy in the video below runs into problems getting the new coolant in. He has to rev the engine to 3500 RPM for 7 minutes just to start to get the coolant circulating.

https://youtu.be/THcMQbOSuZo

That seems like a lot? Have you had to do that? I'll order the no-spill coolant funnel that seems like it's necessary, but I'm concerned about not getting the coolant circulating, not knowing how to bleed out air somewhere if necessary, what to do if it starts overheating, or what to do if I break the plastic petcock valve which I've heard happens all the time.

Is draining via the lower radiator hose an acceptable alternative?

I'm also confused about opening 2 drain plugs and the radiator cap as below, so 3 spots. I only know of the petcock valve and radiator cap.



Finally, to get the reservoir tank out for cleaning, I think I need to squeeze the sides of this steel thing on the side of the tank with needle nose pliers? I can kind of get a pair of pliers in there but it feels like I'm going to bend the steel or break the reservoir trying to pry it off.

 

Follow this one

https://www.tacomaworld.com/posts/14758382/
This link is for the thread to Timmy’s coolant change.

 

You just let it idle till the thermostat opens, you put it on HOT to circulate the heater. Just get a coolant funnel theyre like $1. Just squeeze the big hose to get it in and out. The drain plug is easy. The reservoir just remove battery holder and push it up thats it. Pretty easy. Go look up Timmythetoolman coolant change. if youre not changing the radiator get the cleaning system. pretty easy gl

 

Don't pull any of the drain plugs from the engine block. Just drain the radiator, overflow coolant tank, and pull the hoses. Flush with water or a radiator flush solution kit, drain again, then fill radiator till full and add to the radiator as the thermostat opens and closes and sucks the coolant down. Also, agreed on leaving got heater on full blast during the entire procedure so coolant circulates through the heater core and gets 100 percent of the bubbles out.

Edit: A 2 liter soda bottle cut in half and turned upside down will make an excellent funnel for the coolant to bubble up and burp in the radiator during the refill process.

 

Just do it according to the service manual. I would just but a radiator bleeder to get the air out. It's like $20 at WalMArt of auto parts store.

 

2nd gen 4.0 has an additional drain on each side of the block.
I don't know about 3.4.

Professionals everywhere regularly use a vacuum filler tool. You could try that if you want to guarantee success.
Compressed air flowing through a venturi creates vacuum in the system. Which then sucks coolant in.

I have also used the funnel thing but got rid of mine because it takes up a lot of space.

 

The repair manual and FSM both describe only a drain and refill, so I think I'm just going to try that and not a flush. It was done 60,000 miles ago.

The Timmy video did show getting the reservoir tank out, which is helpful.

To refill it sounds like I should jack up the front of my truck to get an incline, have some coolant in the funnel, start the engine and get it to full operating temp, then blast the cabin heater and stand there waiting and filling the funnel for a few hours until hopefully the air bubbles keep coming out and the coolant all goes in? Then do a brief drive and refill more until I get it all in? Seems like they made it extra hard for ordinary people to get any air out, when some kind of air valve you can pump yourself by hand would solve all this?

 

just squueze the big hose thats the air bleeder

 

A few hours? Not a good idea...use the funnel I showed, it properly bleeds the air out. Been using it for over 10 years on multiple vehicles and never had a problem. Squeezing the hose puts air in. Keeping the heater on full blast isn't needed the heater valve just needs to be open. On low fan is fine. you want the thermostat to be open fully.

 

For some people Yes !

It seems I lose the Radiator cap every time.

I have never had air pockets with the 3.4 The 22r series engines were a real pain.

it seems I have the radiator out once a month for one reason or another.

 

I dont know about your particular motor but I've done cooling system repairs on many vehicles and never had much of a problem getting the air out, definatly not letting it run for hours on end.
Drain the radiator, replace hoses, if you want clean out reservoir, make sure all the clamps and pepcock are tight, fill system with water, turn on defrost, run engine around 2-3k RPM till at operating temp, either let it cool or drain it while its hot, refill with coolant, defrost and rev engine again for a few minutes, top off coolant if needed, go test drive it and accelerate hard to get the coolant flowing quick, check fluid level after, let sit overnight and top off coolant one last time.
As for the fancy coolant funnel, they are cheap enough to buy but I always seem to make a mess when I use mine, if you live in New Orleans you can have mine since I don't like using it but didn't want to throw it out.

 

Great, I'll order the leak free funnel and give it a shot. It sounds like most of the air will eventually come out if I'm at an incline and try a few methods like rev the engine, turn the cabin heater on hot with low fan, and squeeze the upper hose. I was borderline going to add the coolant change for the shop to do in January but you guys are making DIY sound fairly easy and not risky.

Out of 2.5 gallons is it just the last gallon or so that goes in slow with the air pockets, or am I going to have to coax it all in from the start?

 

Drill (2) 1/8th inch holes in your thermostat 90° apart from ea other on the mounting plate of the T- stat

Doing this will allow trapped air to bleed out of the cooling system and also allow the engine to run 10-15 deg cooler


https://www.hotrodders.com/threads/to-drill-or-not-to-drill-thermostat.189999/

 

Did a flush on my 03 recently using Timmy's process. It's not hard but it took time to get all the yellow coolant out to replace with pink.

I second getting the bleeder kit that @stevesnj posted.

 

Also, if you don't know the age of the thermostat get another. OEM toyota brand only and new radiator cap. It's worth the time since the coolant will be drained anyway.

 

Nobody here has the FSM or repair manual. I am jealous of you.

I have never seen any vehicle manual, ever, have guides on flushing.
Only bulletins to flush a contaminated system, sometimes with a cleaner, in the event of fuckery that contaminates it, to resolve that.
There probably isn't guidelines on it, since it's a matter of common sense that doesn't need instruction.

If you fill a system with water, while being careful to not run it that way so long that it causes rust, using distilled water, and not doing that in an area with freezing temperatures that would turn the water to ice which expands to crack the block,
well, that does not really need "guidelines" or instructions.
People also do it when someone put washer fluid or engine oil into their coolant bottle.

The repair manual probably guides on a drain and fill, because that is theoretically what you are supposed to do to maintain the vehicle.
If you are doing the drain and fills when you are supposed to, there is no need to do a flush.
However, if a vehicle calls for a drain/fill every 50k, do you think the average person is doing that? No.
If a vehicle's coolant quality can be measured for degradation with a tool to know when to replace it, do you think the average person is doing that? No.

There are two ways to figure out 50/50 ratio after you have ran water.
1. use a ratio measuring device, to get to that point
2. look up the total capacity of the system, and measure how much water you've put in. The other half should be concentrate.
Or maybe a third way. A final drain of the water. Then a fill of 50/50 premix.
I don't think the specifics matter much. Like if your ratio is 45/55 or 55/45, it probably doesn't make a difference, depending on what climate you're in.

This "air valve" you speak of sounds like a manual hand pump vacuum bleeder. To my knowledge, no such tool exists, made for the DIY'er.
For around $100, you can buy a pneumatic vacuum filler. It takes a lot of 90psi shop air to flow through that tool, to create needed vacuum.
Something that would be hard to achieve with a slow manual hand pump.
On mine, I don't know why, it would not hold negative pressure. Probably because the system was still partially full and not drained from the block drains. I just drained some out from the rad to make room to pour in an additive.
But this may be normal. (to not hold vacuum if partially full). I simply did the refill fast. So far temp is stable, no overheating, no leaking visible.
Gotta say, I'm not a fan of how shitty the radiator drain petcock is. Looks like it can easily break off and is hard to operate.
I guess I should be replacing the rad anyway at this years/mileage so that would help this preventatively by having a new drain valve in there as opposed to one that I've already operated twice now.

Last time was to run a water flush due to unknown service history, and it didn't cause any issues.
At that time, did not have a vac filler. Used the gravity funnel tool, with front end lifted high, running, and heater/defrost on max in the hopes it opens any valves to circulate coolant through the heater core part of the circuit as well, to make sure there is no air there either.

Yes. At this years and miles, probably not a bad idea to put new:
-radiator + cap
-thermostat
-water pump
-coolant

while in there, can look at all of your accessory drive belt stuff like belt, tensioner, pulleys

IDK if it's worth getting the TRD radiator cap that holds a higher pressure. I have heard this higher pressure can stress the radiator more and cause it to burst from the plastic end tanks.
On the other side I have heard it recommended for proper cooling system performance during high altitude rock mountain wheeling, where atmospheric pressure is lower, reducing boiling point. So that the cap can counteract that with higher holding pressure.

There are cooler opening temp thermostats available to buy. Possibly including from URD.
However, supposedly this requires tuning.
To my knowledge, the stock ECU map is configured with certain operating temperatures in mind. I imagine if you simply change the tstat temp without anything else, it could fuck something up.

At minimum, engine operating temp may be a factor in emissions. Hotter running engines may pollute less. Which most people won't care about, understandably, as the planet is fucked regardless.
I don't know if running hotter increases MPG.
For example, what if the ECU dumps more fuel, in an effort to warm up and reach an operating temperature?
Now all of a sudden there is a colder thermostat preventing reaching of that temperature. What if the ECU interprets that as needing to waste more fuel as warm-up strategy?
Maybe it is done more on older models with a less sophisticated ECU

 

The vehicle doesn't need to be inclined (jacked up in the front) to refill, flush, or bleed the coolant/coolant system.

 

I checked records again, and thermostat is only 4 years old, radiator 9 years old, drive belts 4 years old. I'll replace any small water hoses I can easily get to with some bulk hose, and OEM radiator hoses and OEM clamps that I have ready. That's about it for now. Things are generally in pretty good shape and the weather here is mild year-round.

Good to hear about no need to jack up the front! My garage is a minimal incline per building codes.

 

here's my 2 cents. just drain and refill normally. after the job is done run the truck with the heater on to let air bubbles escape. your coolant reservoir is there to exchange air pockets in the system for coolant. run the truck normally and make sure you have plenty of coolant in the reservoir.

also, you said you have 3 gallons of toyota coolant? concentrate or 50/50? you need 3 gallons of 50/50. 3 of concentrate is too much unless you really want lots of extra. like 3-4 gallons of extra after you dilute it to 50/50.

keep in mind, this video is for a truck designed by marketers a.k.a. people who don't think. our 3.4s were deisgned by engineers. you don't have to worry as much with our trucks as you would the 2nd gen+

 

Haha, too bad with marketer made trucks. Architects do the same thing with homes. They do what's gonna look cool for their portfolio photos. The home is never optimal for living and moving around in.

Yep, 3 gallons of 50/50.