Coolant Drain & Fill

Doing my first coolant drain & fill at 55k miles. Should the engine block be drained as well? And would doing so make it more difficult to burp the system? Wondering if I should just drain the rad. and do it again at shorter intervals like 30k thereafter. Thanks in advance.

 

only radiator. start meddling with block and easy get it wrong, overheat and die.

 

This is what I’m concerned about so leaning towards the rad. and shorter intervals.

 

You could drain and fill a few times to get additional "old" out. Multiple videos online showing the procedure.

I would suggest investing in one of the funnels that attach to the radiator cap to help when running/burping/bleeding the system. Can also jack up the front end to help getting all the air bubbles out.

$20 OEMTOOLS 87009 No-Spill Coolant Filling Plastic Funnel Kit | Universal Radiator Funnel for Auto Mechanics | Adapters Help Funnel Fit the Radiator of Most Every Consumer Vehicle | White

https://www.amazon.com/OEMTOOLS-87009-No-Spill-Coolant-Filling/dp/B01A2CQSU6

 

Yup, picked up one of those funnels and plan on jacking the front end up a bit too.

 

I flush my motorcycles with distilled water a few times then refill with anti-freeze.

 

I'm no expert, but this guy drained block:

https://youtu.be/ZkqGjj3L05Q

Has anyone had problems doing this?

 

I did this on my older 4Runner and it worked but on my newer 4Runner I am doing the 30k change on just the rad like the Vikings Garage shows to do.

It’s rated up to 100k so my assumption is that dumping just the rad every 30k should work and keep it fresh enough and well under the 100k life.

 

I’ve watched and referenced his video. It’s the best one out there but I’m a little paranoid about having some trapped air in the system or developing a leak at the block drain and overheating so I just drained and filled the radiator (4qts) and the reservoir yesterday with no issues and very little bubbles. Recommended coolant interval is 50k or 5yrs. I’m thinking of doing just the radiator half that every 25k. A gallon of coolant is cheap.

 

This looks pretty easy.

This is what I would do.

 

for reference, here is the Vikings Garage video. In the comments, I get the sense that he only drains the radiator for simplicity and does it every 30K instead of 50-100K. Some comments suggest removing the thermostat is another option for draining the block.

https://youtu.be/OP9kI8Rpzgw

 

THis is garbage.

OP drain the block. Its child like simple.

 

Dont do this on the Runner, it throws off the ratio of coolant. More of a concern the farther north you live.

 

On a very simple, low volume cooling system that's fine. Totally unnecessary on a 4Runner. Drain and fill, done.

 

Yeah, along with T4R Garage I reference a bunch of his videos along with Car Care Nut’s before doing any work.

 

I just did a coolant change on my '19 SR5. Steps:

- Jacked up front of vehicle.
- Drained Radiator (3/8" ID tubing)
- Drained Block (5/16" ID tubing)
- Drained about 2Gal total
- tighten radiator drain hand tight and block drain to 9 ft-lbs.
- filled using fill kit shown below -- purchased at O'Reilly auto parts
- got probably 1.75Gal into system very easily while off
- waited until bubbles stopped and started vehicle
- turned on heat
- waited until vehicle got to temp
- set timer for 10m
- after 10m, still blowing cold air -- no heat in the vehicle
- rev'd engine a few times
- lowered front end to ground, raised it back up, etc.
- during this time a few more bubbles came out and started getting heat in cab
- let it run for another 10m or so -- a few more bubbles during this time
- got most of 2 gallons into the vehicle and put the remainder from the funnel until the overflow reservoir

I'm pretty sure I did not get quite as much fluid back into the vehicle as I drained out, but very close. Hopefully it will pick up what it needs from the reservoir.

Was also surprised at how long it took until the heater started working -- must have been some air trapped in the heater circuit.

Thoughts? -- am I missing something, or is this a fairly normal experience?

Do you ever have to add a little coolant in the weeks following a drain and fill?

 

A few suggestions from Perplexity -- its AI, so may or may not be helpful:

1. A small amount of trapped air is normal after the first fill, but it should be minimal. If you only need to add a tiny bit of coolant after driving, you've likely removed most of the air.
2. Air bubbles can work their way out after a couple of drive cycles. It may take a few heat/cool cycles for all the air to naturally burp out of the system.
3. Trapped air can cause hot spots in the engine, so it's important to remove as much as possible.
4. To remove air from the system:
   • Park on an incline with the front end higher.
   • Run the engine with the radiator cap off until both upper and lower radiator hoses are hot.
   • Squeeze the hoses to help release trapped air.
   • Use a funnel or makeshift device to prevent air from being pulled back in.
   • Set the heater to maximum to open the heater core valve (if applicable).

 

Thanks for the write up.
I only have experience draining the rad. Super easy to burp. I jacked up the front too and only encountered a few bubbles. Got heat really fast.
Do you know how much you drained from the block? I’d be curious to know how much burp time you need draining the rad. vs. draining the rad. and block. Also had you drained the block before? How tight was the block drain bolt?
I read you’ll need to watch the reservoir level for the first couple hundred miles or so as well as your temps. No matter how well you burp the system air will continue to work itself out those couple hundred miles.

 

I think I got about 1 gal each from radiator and block.

How much coolant did you add when draining just the radiator?

This is the first time I've done this as 4R is pretty new to us. 67K miles and ~5 years old pretty much everything is due. Got through the diffs and xfer case oil changes. Need to do engine oil, trans, brakes, etc. yet. So far, it has been enjoyable to work on.

Block drain was pretty tight to get open, but not impossible with a socket and long extension -- I searched and it said to tighten to 9 ft-lbs, which seems reasonable as it looks like it is brass.

Took a long time (30+ minutes) to burp until I got heat.

Thanks for confirming I need to watch levels/temp for a bit -- will do.

 

Thanks. I got 1 gallon, almost precisely, out of the rad. Instead of the block I think I’ll just drain/fill the rad. (half the volume, half the interval) every 25k. It’s a long enough interval where it’s not annoying and it was quick.
Yeah, like my old Subaru WRX lots of DIY info out there and the 4R is just as easy to work on.

 

This is on my near future to do list but I am wary of running the engine with trapped air in the engine block. My understanding is that it doesn’t take much to damage an all aluminum engine block.

 

just buy a new 4runner to avoid all this troubles

 

Don't be afraid of this. Get the funnel, watch a few videos on burping it. What is key on the 4runner is even the best burping will not eliminate 100% of the air in the driveway. Depending on how much you drive, the coolant level can continue to fall in the overflow tank somewhat until every last bit of air escapes. In my case it took 200 miles +/- as I don't have a long commute. I used blue masking tape to mark cold level and monitored for a month or so until it leveled out.

 

I just did a drain and fill using this method. Worked out great. That funnel is awesome!

A little less than a gallon came out of the radiator and about the same came out of the block.

A couple of small issues I had with the video was that the block drain plug bolt size was 10mm and not 9mm. Also, he said the tubing to connect to both drain plugs was 3/8 ID. Either Amazon sent me the wrong ID tubing or the drain plugs are slightly smaller because my tubing was slightly too large, which made things a bit messy at times.

Rather than removing the reservoir to dump the old coolant, I just used an old turkey baster to get it out.

All said and done (including the reservoir drain and fill) I used 2 gallons of Toyota long life coolant. Got it for around $20/gallon.

 

Someone here mentioned opening the radiator drain with the radiator cap still on, and that will empty the reservoir bottle. Once it’s empty, open the radiator up to quick drain the rest. I did it… worked great with no extra work, and no extra tools to clean off.

 

Same here with 10mm.

I used 5/16" ID tubing on the block drain, and 3/8" ID on the radiator.

https://docs.google.com/document/d/1Q7trJy3NU5dI0kF2gQA5qrAb55b8OG9LKXcmxeUPYQ8/edit?usp=sharing