Procedure - Flushing Cooling System? Help Please

sant6236

sant6236

New member
Hey Guys~

I am brand new here, that is as an actively participating member. I will be providing all of you with pics of my Toyota 4Runner 2001 SR5. It has man mods and personal touches.

My inquiry relates to that of the proper procedure to flusing my cooling system. Can someone provide me with this link or procedure?

Lets just say I am one of those guys who had their transmission coolers explode within the radiator, resulting in radioator fluid in the transmission and transmission fluid in the radiator.

I am almost positive I will have to flush this for the second time, the radiator that is. I have been observing the coolant reservoir, including the coolant inside the radiator. There is left over strawberry milk shake.

Any help would be apprecaited.
 
Last edited:
Register to hide this ad
Ive done this procedure a few times on my 98 with no issues.

1) When engine is cold, remove radiator cap and drain plug (white twist plug on the bottom right side of the radiator, I believe you can get to it through the skid plate with with pliers)

2) Flush radiator with fresh water (garden hose)

3) Remove overflow resorvoir and flush it out with clean water

4) Fill radiator with new coolant

5) Run vehicle with heater on until thermostat kicks in (upper hose will get hot). Shut vehicle and squeeze upper radiator hose with radiator cap off to remove excess air.

6) Top off radiator and fill overflow past min mark

I have also read that it is advisable to remove the plug on the engine to flush any coolant that may be there, but have never been able to find this plug.
 
Last edited:
Wonderful advice.


When you say "remove overflow resevoir", do you mean I have to take the entire reservoir off?

Also, when you say "run vehicle with heater on until thermostat kicks in," do you mean completely start the engine or just ACC? Does the overflow resevoir have to be installed to do this?

How do you know when the thermostat kicks in?

In step (5), does the vehicle have to be shut OFF when squeezing the radiator hose? I believe you intended to say Shut OFF, but just missed it.

One last thing, what do you use to fill the overflow resevoir? Cau you use the same antirfreeze that you are filling the radiator with?

Lots of questions, I know, but I cant tell you how much I appreciate it.

Thanks
 
Last edited:
When you say "remove overflow resevoir", do you mean I have to take the entire reservoir off?

It depends on how much "crud" is in there. You say your collant is "milky", so I would recommend doing it. I removed it in order to flush with clean water and clean out any deposits that were on the bottom.

Also, when you say "run vehicle with heater on until thermostat kicks in," do you mean completely start the engine or just ACC? Does the overflow resevoir have to be installed to do this?

Start the engine with heater on. Yes, install overflow reservoir.

How do you know when the thermostat kicks in?

The upper radiator hose will get hot.

In step (5), does the vehicle have to be shut OFF when squeezing the radiator hose? I believe you intended to say Shut OFF, but just missed it.

Yes, shut off, remove cap carefully, and squeeze the hose. You will see some bubbles come up through the coolant

One last thing, what do you use to fill the overflow resevoir? Cau you use the same antirfreeze that you are filling the radiator with?

Yes, same mixture you use in the radiator. Don't need to fill it as this is overflow. I usually fill halfway, then monitor. It will usually end up filling the rest with overflow.

Hope that helps.
 
Last edited:
Well Done!

When flushing, do you recommend having the radiator plug @ the bottom on or off?

If it is on or in, the excess water/anti-freeze will start coming out of the top of the radiator, correct?

I ask this because a guy at a transmission shop told me to do the following when flushing it:

Remove the primary fat hose that goes into the radiator and stick a garden hose in that way and leave the radiator plug in @ the bottom. This just seems like it would make even more of a mess because it will all be forced to go out th top as opposed to the bottom, what are your thoughts?

I guess it might be quicker to do it from the top, considering that the opening is larger.
 
Last edited:
sant6236 said:
Well Done!

When flushing, do you recommend having the radiator plug @ the bottom on or off?

If it is on or in, the excess water/anti-freeze will start coming out of the top of the radiator, correct?

I ask this because a guy at a transmission shop told me to do the following when flushing it:

Remove the primary fat hose that goes into the radiator and stick a garden hose in that way and leave the radiator plug in @ the bottom. This just seems like it would make even more of a mess because it will all be forced to go out th top as opposed to the bottom, what are your thoughts?

I guess it might be quicker to do it from the top, considering that the opening is larger.
Click to expand...

I flushed mine by leaving the plug on the bottom off, and running water with garden hose through the top. In my humble opinion, this should flush it out well enough. Trust me, the process is so simple that once youre done, youll wonder why you ever paid anyone to do it. Additionally, the feeling you get knowing that it was done right by doing it yourself is priceless.
 
Thanks for the qucik replies:

I will take your word for it.

How do you know when the radiator has had enough antifreeze, whens it comes to the top?

Is the plug challenging to get off at the bottom? I konw the skid plate is one of the distractions but I think I may jsut take skid plate off to begin with. Makes for less of a mess and more room to work with. Your thoughts?
 
sant6236 said:
Thanks for the qucik replies:

I will take your word for it.

How do you know when the radiator has had enough antifreeze, whens it comes to the top?

Is the plug challenging to get off at the bottom? I konw the skid plate is one of the distractions but I think I may jsut take skid plate off to begin with. Makes for less of a mess and more room to work with. Your thoughts?
Click to expand...

Just fill the radiator, wait until it settles, then top off.

I was able to reach in and loosen the plastic plug with pliers, the unscrew with my fingers without having to remove the skid plate. It would definetly make it easier/less messy if you take the skid plate off, but its not necessary.
 
By the way,

How do you remove the overflow resevoir?

Does it just snap out?

I feel like I owe you for your efforts.
 
From what I recall, it just snaps out if you push up on it. I cant recall if there are any bolts to remove (will verify tonight)
 
Yes, I gave this a try and it merely snaps out when pulling up on the resevoir.

You have been a tremendous help with this issue.

Thanks
 
toyota4life~

This is where I stand.

Everything went almost perfect until the last flush and fill.

The petcock simply is not sealing the small hole directly underneath, which seals when the petcock is fully twisted in.

The first two drain and fills went fine and the petcock sealed it not problem when I wanted to stop draining.

In the midst of my final drain, I attempt to close the petcock to then add the near 2 gallons of antifreeze to the radiator and the petcock would not seal the small hole below it.

There was absoloutely nothing cosmetic or externally alarming that would trhow a red flag. It twisted perfect and sealed in all the way, but did not stope the draining.

Meanwhile, I had to compensate by plugging it with a small bold that is currently sealin it off. There is not leakage and it can be easily removed.

As for the petcock and as I stated before I took it out, examined it for deformit or anything else and could not fine anything wrong with it that would cause it to be malfunctioning.

Maybe an O-ring inside? I dont know.

What are your thoughts?
 
By petcock, I assume you mean the white plastic radiator drain plug?
If so, I am not 100% sure on this, but I believe there is an O ring that is on the petcock. See if you can stick a finger/scredriver in there and pull it out. Again, I am going off of memory. When I get home tonight I will check my Chiltons manual to see if it mentions an O ring.

I think the best thing to do would be to get a new one from Toyota dealership (assuming hopefully you have another vehicle to drive).

Let me know how you make out.
 
Ok, I wil ltry that the next time I flush the radiator, which will probably be within a month.

I have a feeeling this will be an almost lifetime commitment to keep flushing until all ATF residue is gone.

Ther may have been an O-ring inside that drain plug and yes this is what I was referring to as the petcock. However, I can not recall ever seeing one. I just know each time I drained and filled before the final, it sealed the little hole off completely and perfectly.

I will not be able to check if there is an O-ring inside until I drain it oagain but will definitely keep it in mind.

For now, I think I am going to call the local radiator shops around here to check and see if those petcocks come with O-rings to help seal the drain.

Thanks Again.
 
Well, the radiator was still under warranty.

I am having them put a new one in today.

I am driving about 9 hours to Boise, ID on Friday and if antifreeze starts coming out of that draincock, then we are screwed.
 
Ok Everyone~

To sum this up. The draincock would not seal the hole because of a missing O-ring that most likely fell out when I was draining it.

They did not replace the radiator, as for this was the only thing wrong with it.
 
toyota4life said:
Ive done this procedure a few times on my 98 with no issues.

1) When engine is cold, remove radiator cap and drain plug (white twist plug on the bottom right side of the radiator, I believe you can get to it through the skid plate with with pliers)

2) Flush radiator with fresh water (garden hose)

3) Remove overflow resorvoir and flush it out with clean water

4) Fill radiator with new coolant

5) Run vehicle with heater on until thermostat kicks in (upper hose will get hot). Shut vehicle and squeeze upper radiator hose with radiator cap off to remove excess air.

6) Top off radiator and fill overflow past min mark

I have also read that it is advisable to remove the plug on the engine to flush any coolant that may be there, but have never been able to find this plug.
Click to expand...
You should never flush it with regular water... especially on a 3rd gen where there is a risk of causing a strawberry milkshake. Distilled water only!
 
You must log in or register to reply here.

Members online

Total: 417 (members: 5, guests: 412)

Forum statistics

Threads
278,307
Messages
3,554,054
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top