FJ40 2F Engine Coolant Flush & Fill Maintenance

[Ackcruisers]

Do not defer your 2F coolant flushing.…

The FSM says to “change coolant if excessively dirty”. Well, my coolant was a 50/50 mix of Toyota coolant and did not appear dirty but wanted to flush and fill anyway. Glad I did.

First, my radiator is an aftermarket 4 row type made by CSF. The drain plug is annoyingly off set inside the 53108-60013 radiator support making it difficult to use the plastic drain plug. I decided to just undo the lower radiator hose for each time I drained and flushed the system. The drain plug size is an M10x1.50. I contacted CSF directly to order a replacement plug, in the event I ever break it, and they have none in stock nor could they confirm the plug thread size.

Image below shows the drain plug offset. This has been well documented on ih8mud with several creative options to solve for it but no vendor @ToyotaMatt has yet to offer a proven extension and petcock product. I chose to experiment and make my own but am on the fence with using it. It will be a back up to my plastic plug.

Opened the petcock block drain and drained the block. I used a hose to direct the flow into a bucket. Then, installed a temporary back flush hose fitting into my 5/8” heater hose and connected my water hose, I first just ran tap water then back flushed it with distilled water using a pump as shown. The water was pumped with pressure from the back of the engine up to the top of the radiator and also out the block drain.

The radiator coolant appeared clean upon inspection per the FSM but look at what was found after flushing. This is metal as you can see it sticking to the flashlight magnet bottom.

Once this was discovered, I opted to try Thermocure by Evaporust now CRC.

Followed their Instructions and then drained and flushed several times until no more rust flakes drained out. Each time I filled with distilled water I used a cheap $35 vacuum filler to not worry about having to burp it each time. It was a huge time savor.

Next I changed my water pump bypass hose and then upgraded all hose clamps to the OEM type made in stainless steel by Cityracer.

Also, I inspected my thermostat but did not remove it during the fill and drain process. The bypass hose is there to recirculate the fresh clean water in the head and block.

Finished by filling with 50/50 red Aisin coolant and now ready for fall/winter.

 

[brian]

Ive not had good luck with the city racer clamps on non oem hoses.

 

[Ackcruisers]

Thanks. I’ll keep an eye on mine. The vacuum filler evacuates all air and if it holds vacuum, theoretically it confirms clamps are holding. Things change, move and expand and contract... Time will tell. What clamps do you run on non OEM hoses?

 

[brian]

whatever worm clamps. in my case, i nearly ran out of adjustment on the clamps when the hoses were new...once everything aged a little, i was chasing water leaks and was unable to tighten the clamps any further.

After looking, the hoses i had problems with, actually are oem...the double clamped upper hose, was an on the road parking lot job....i just haven't gotten around to removing the wire clamp...a year or two later.
The smaller dia clamps are good, with plenty of adjustment left in them.

 

[Green Bean]

I like the look of the the OEM-style hose clamps, but like @brian I had difficulty getting a proper seal. I ended up going with ½" Solid Band Scandvik Hose Clamps (www.fisheriessupply.com)(# 382003, 382005, 382001, and 382009 (I ordered 8 size 10's, 4 size 20's, 4 size 24 and 10 size 28's ) I believe these were recommended by @GA Architect in his exceptional build thread but I may be mistaken.

 

[mattressking]

I just use oem hoses, clamps…no issues ever on multiple/many F’s/2F’s?

If not non oem hoses for NLA hose and oem clamps are just fine.

I’d likely be curious why you have clumps of rust - that’s either from your rad or leftovers inside cooling chambers in motor most likely. Since your truck is South American - can you trust the details if you haven’t seen inside the cooling area in the block? I usually inspect and blow out/rinse then dry with compressed air/brake clean etc.

 

[Ackcruisers]

The engine was rebuilt, not by me or with my direction, so it is likely the Colombian shop never cleaned out all the rust.

The rust came out of the engine block drain. I’ve learned that rust flakes settle to the rear section of the block near the drain plug.

Images of the engine being taken apart.

 

[kerplunk]

I went through similar several years back. Except that I'm pretty far from a toyota purest and used prestone. (but I did have a toyota radiator and drained easy on the stock valve / peacock).

Leaving the cap off that T on the heater hose allowed me to park on a small hill (ramps would work) and leaving the cap off that T, fully full the system without any need to vacuum, burp, etc...

And, since I only have septic, and getting rid of any kinda chemical "safely" is always kinda a questionable annoyance, I used vinegar (it's an acid), filled it up and drove till hot and then another 10 minutes before flushing.

Was rewarded a week later with a growing series of pin holes along the seems of the top tank on my radiator. Must have done a bit too good of a job cleaning.

 

[1MOA]

For a 50 year old iron block engine that's not a lot of rust at all.

 

[FLoudog]

where can I buy that vaccum filler? also is that a tool good for checking for leaks?

 

[dmaddox]

Thank's for the post, @Ackcruisers !

 

[Ackcruisers]

where can I buy that vaccum filler? also is that a tool good for checking for leaks?

The vacuum filler was bought on Amazon. Here is link. Once the vacuum is applied, it should stay for a few minutes proving no leaks.

 

[GasganoFJ60]

Good writeup.

I know this is a can of worms, but..

Is the red Aisin coolant compatible with the old F engines?

 

[charliemeyer007]

AISIN

aisinaftermarket.com

I didn't see red listed

 

[red66toy]

You can run red or green. Green is more common and at the period the engines were built was the standard of the day. Red is spec’d on newer Toyotas.

The most important thing is to perform flushes in normal factory intervals.

 

[Grayscale]

Thanks, Arkcruisers. It is always inspiring to see your level of thoroughness.

I've never done a coolant flush on my current rigs. I always have just bled the radiator and block, and replaced the coolant. However, the last time that I did a coolant change, I noticed how fast the seals on the radiator cap were stiffening up. They appear to deform and stretch-out, particularly on the inner seal. I've decided that I'll use a new cap for every coolant change.

I bought a cache of aftermarket radiator caps, as the other rig needs them, and they are the same part for both vehicles. So, I'm out a few bucks (RockAuto), to start fresh, without sediment under the vacuum poppet. The flow of anything solid between the radiator and overflow tank can build-up under this critical metal piece, and possibly interfere with the way that the system holds pressure. Plus, I want soft, fresh seals to hold pressure if something solid does get trapped here.

In addition to changing coolant, I unbolt the overflow tank, and remove any sediment. During the last coolant change, I noticed considerable corrosion on the OEM cap, and under the pick-up tube in the overflow. Although the radiator side was still green, the overflow was off-color.

The Owner's Manual says that "Hard water and alkaline water should never be used under any circumstances." Our municipality uses some aquifer water, so the distilled water is a good investment. Plus there is chlorine in tap water, which is supposedly bad for rubber seals; I'm assuming that the cooling system uses rubber, albeit an oil-resistant type.

My guess is that Dorman 490215 will fit the aftermarket CSF radiator? (edit) at least for a gasket

 

[Grayscale]

I could probably get an M10x1.5 nylon screw from McMaster-Carr, and the gasket from Dorman, for a replacement petcock for the CSF radiator. However, I'm sketched-out by that. I sent an email to CSF, just to see how they respond.

All things considered, pulling the lower radiator hose remains a slightly more attractive option? I'm a fan of the band clamps, the cool-looking wire ones distort the hoses a bit much, and they twist and bend when the threads get kinda rusty.

Even for the rebuilt OEM radiator that came with my truck, it had a frozen drain plug / petcock , and I really made the radiator casing flex when I finally got the petcock removed, uninstalled, out of the truck.

 

[sleepycruiser]

You can run red or green. Green is more common and at the period the engines were built was the standard of the day. Red is spec’d on newer Toyotas.

The most important thing is to perform flushes in normal factory intervals.

Can I use red or green on an F engine 1964 FJ40? I was thinking about just getting Zerex Red since I use that in my 200 series and would be nice to have all one coolant. Of course for the 40 I might get Supertech Red….if it will work ok and not damage any gaskets, etc. Cheaper and likely the same.

Or should I go green? Or yellow? Supertech has the yellow and it says it will work in any vehicle. I assume it is all dyes anyway.

A lot of people rag on SuperTech, but I’ve used their oil for years.

 

[red66toy]

Can I use red or green on an F engine 1964 FJ40? I was thinking about just getting Zerex Red since I use that in my 200 series and would be nice to have all one coolant. Of course for the 40 I might get Supertech Red….if it will work ok and not damage any gaskets, etc. Cheaper and likely the same.

Or should I go green? Or yellow? Supertech has the yellow and it says it will work in any vehicle. I assume it is all dyes anyway.

A lot of people rag on SuperTech, but I’ve used their oil for years.

You can run red. I think the main issue is you just do not want to mix these coolants. So if you go to red, make sure you flush all the old coolant out.
Green is of course the classic and for sure works. Yellow also supposedly works too.
I am running Zerex red in my 65. Seems happy to me.

 

[S.CarolinaFZJ80]

I run Toyota red just so I can stock one type of coolant for all my Landcruisers.
Like red66toy said if you choose another color, just be sure to give it a good flush first