All right, I’m going to post this at the risk of the “covered a million times” “did you search first” etc… blasts that are sure to come. Yes, it’s been covered a million times, as I just found out after spending the last 1 & ½ hours searching and reading the posts but I am still confused and have more questions that I couldn’t find the answers to, hopefully someone can help?
(1996 Tacoma 4x4 v6 3.4L 150,000 mi.)

1. Just for clarification, it did seem from what I read that I definitely want to use the Toyota Red coolant, correct? And at an approx 50/50 mix rate, maybe a little higher coolant to water ratio for hot weather climates like mine? (Sacramento, Ca) 60/40 or 70/30. It has green stuff in it now, so I am going to completely flush it, with chemicals first though, to be safe.
2. When flushing, I found the “procedure(s)” I can handle that, thanks for the info. all. I did wonder however, would there be any benefit or harm if after I flushed it till clean water came out, I ran it for a while? Couple hours? Couple days? with just plain water in it and then flushed it again? Or even run it for a while, hours, days? with plain water and the flush chemicals? Just wondering if that would scrub it better or if it might damage it?
3. Is it recommended to change the thermostat too or only if there is a symptom indicating such?
4. What is “Water Wetter”? what does it do? How much? Where to get? Good or bad to use? Never heard of it?

Thank you for any and all help and info, much appreciated!

 

well i just did mine recently when i did a timing belt/water pump change. all i did was take out the thermostat, and run water though it for about 10-15 minutes. water was clear and then i just filled it up with the toyota red. it's all running good. i don't recommend running with just water only. it's a coolant for a reason.

 

Running water only should be okay, as long as you dont get it hot. Coolant keeps it from boiling at 212. With a pressure cap you will boil pure water above 212 anyhow. I usually like to run it clear, put the flush in, run it clear. I always let it got good and hot, heater full hot.

Running a greater that 50:50 will yield a higher boiling point/lower freezing point, however; it also holds heat longer. So if it does get really hot it is slower to cool than a 50:50 mix. Toyotas have never had a problem with overheating (assuming your system is working properly), so just run 50:50. 60:40 would only help you if you are always getting in the redline are, then you have other issues, like warping a head.

Get a good longlife coolant. My favortie is the Cat coolant, also marketed under chevron and texcao labels.

I prefer to change the thermostat at the same time, its fairly cheap, and you spill coolant when you change it, so why not change it with the coolant missing?

Your going to change the hoses too right?

 

thanks AH, good info. to know. I was thinking of doing the hoses and saving the existing ones as "trail spares"... sounds like a good idea. For most of my other vehicles I have always saved the known good spare parts that I have replaced for PM and kept them in a kit for emergency repairs and also helps to diagnose potential future problems, cuz you can do a swap with a known good part and see if it fixes the problem!
thanks,

P.S. just saw the ads for the Disco channel "future weapons" where they are doing the AH-64D LongBow. Looks like a fun toy!

 

I agree, I do the same thing..

 

Answers in red above.

 

i'm in sacramento.. i just run water through the block/radiator until it's clear, then drain everything completely (no removing the thermostat, no other chemicals, no running the engine with only water...). Once it's drained, fill it up with 1 container of the toyota red, then top off with hose water. worked fine for me for years.

 

Got a stupid question... when flushing, do you do anything to flush the overflow container? I've obviously never done this before, and think I have the overall steps involved with the exception of not knowing how to get the old fluid out of the container. Is it as simple as pulling the reservoir out and flushing it? Thanks

 

I remove mine, rinse and scrub as necessary...

 

Thanks AH!

 

Hi there,

1. Yes, Toyota Red is a must... As far as the ratio... I thought that 50/50 may be best if you want to store or drive your car safely at really cold tempetures. But it's not the best mix to help your cooling system get rid of the engine's heat. Isn't water the best heat transfer fluid commonly available. So the more water in our system the better. Of course you have to take into consideration your climate.
Here's a chart that was provided to me. It says to run the "least" amount of coolant you can in your system that will provide freeze and boil over protection "for your climate". All figures are in degrees fahrenheit.

% Coolant (Freeze - Boil)

20% (16 to 253)
33% (0 to 256)
50% (-34 to 265)
70% (-90 to 277)

This info was provided to me for my Toyota Supra - Turbo. Perhaps is different for our trucks.

2. Please let me know where I can find the procedures to flush our cooling systems. I'm planning on doing this to my 4runner.

3. A bottle of redline's water wetter will help reduce cylinder head temperatures and provide water pump seal lubrication. Water-wetter is highly recommended because it has helped produce measurable increases in gas mileage with reformulated gasoline. Reduction of cylinder head temps allows more ignition advance before onset of knock, and more ignition advance is conducive to better fuel economy. It's about $12 bucks in Autozone.

Hope this helps,

 

Yes, I'm resurrecting a semi-old thread, but I'm getting ready to flush my coolant and wanted to make sure I get it right. From various threads and online guides, this is how I understand the process (I'm omitting a chemical flush, thermostat replacement, and water wetter):

1) Open radiator cap (with engine cool and not running)
2) Drain coolant from radiator
3) Fill radiator with distilled water
4) Replace cap
5) Run 4runner for about 10mins, idling with both front and rear heaters on full-bore
6) Let cool until you can touch the radiator cap without burning your hand
7) Repeat steps 1-6 until only clear water is being drained from the radiator
8) Remove overflow tank and clean it out with distilled water.
9) Reinstall overflow tank (empty)
10) Fill radiator with 4.75qts of Toyota long life red (a 50% mix for a model with rear heat)
11) Fill remaining capacity with distilled water
12) Run engine with heaters on and radiator cap off
13) Keep filling with distilled water as the engine warms up at idle
14) Once the thermostat opens, give the engine a few good revs
15) Then fill radiator until full and reinstall cap
16) Fill overflow tank with 50/50 mix of distilled water and coolant until it is between the min and max lines on the tank.

Please correct me if I'm screwed up anywhere in this process, or if my omission of a chemical flush is a bad thing (what flush chemical is recommended).
- Thanks

 

Almost as good as an oil thread....

Toyota long life coolant is good.

Evans is really, really....space shuttle good. So, if you never want to change your coolant again, go with Evans. If you do, go with Toyota pink.

Someone along the way put that green in my truck. It still tests out ok but will soon be undergoing the evan's flush.

 

I follow this until #16. With 4.75 qts of fluid already in the system, you should add only distilled water at this point to reach a 50/50 mix. In #15, you reinstall the pressure cap. I think you should wait a few minutes for the coolant to expand and enter into the tank (since now it is under pressure). Then move on to #16, but only add water.

 

I've been away from Toyota maintenance for too long, a 9 qt cooling system is TINY! I hold almost that much in my rear diff now, my cooling system is just under 8 gallons!!

 

I don't think the cooling system capacity listed in the manual includes the overflow tank so that should be filled with a 50/50 mix also. Even if I am wrong, it wouldn't be enough to make even a tiny difference. You might have like a 55% coolant mix in that case, but it's ok to run up to a 70% mix especially for colder climates like Canada, Alaska, etc..

 

Your going to want a couple of hours before you drain and refill the block. The radiator cap will cool down pretty quickly but the engine block will still be pretty hot. By refilling the hot block with 80-90F water (assuming bottle of distilled water sitting outside) or worse 60F hose water can cause thermal shock which can result in a cracked block, heat gasket failure, ETC.

Remember that the cast iron block and the aluminum heads have different coefficient of thermal expansion so if they are cooled too quickly one will contract faster than the other.

The best way to check and see if the block has cooled down is to turn the key on and see if the temp gauge is pretty close to the bottom. If it is then its OK to drain and refill.


FOG

 

While its not a bad idea to wait, I doubt you do anything to the block. What do you think happens when you have the thermostat open and it -10*F outside?

Also never use hose water in an engine, only use distilled water. At .78c a gallon its too cheap not to use.

 

The thermostat is going to slowly open and as soon as the temp in the block drops a couple of degrees its going to shut. It will do this a few times till it find a happy medium. Its not doing to allow the engine to suddenly just be rapidly cooled.

Whats happening with water hose or distilled water dumped in the engine is a totally different animal. Your taking almost empty block and suddenly filling it will water that's almost 100F lower in temp which will cause rapid contraction.


FOG

 

Yes its slower, but if you have ever watched the coolant temp on an OBDII scanner in cold weather you will know that the temp drops 10*+ instantly, and thats at the thermostat which is the hottest part of the block, at the inlet to the block you have just dumped 200* colder water into the block and nothing bad happens.

Your only talking a very small temp change, the block will not cool that rapidly especially in a 9 qts system, of which 50% or more is probably in the rad, its not going to hurt the block.

I still don't think waiting is a bad idea, but you won't hurt anything.