FJ40 coolant flush

[cws57]

Guys:
Good afternoon.
Still working on my '78 FJ40. Today getting ready for winter here in Idaho I was going to replace the coolant. Unscrewed the pet cock and nothing came out. Using an ice pick I managed to dislodge what must have been years of dirt and slug. Liquid came pouring out but I only got about 2 gallons. I replaced the pet cock and fill the radiator with distilled water (around 2 gallons filled the radiator), ran the engine to temp and drained again. I still only got out about 2 gallons. I know the capacity is 19.9 quarts or just shy of 5 gallons. Am not letting the engine get hot enough?

Given this is likely the 1st flush the coolant system has seen, how many times should I flush before refilling with coolant.

 

[1969FJ]

I believe there is another access port on the block , near the rear, that also drains the block. And that one can be a bear to remove the crud.

 

[ToyotaMatt]

I believe there is another access port on the block , near the rear, that also drains the block. And that one can be a bear to remove the crud.

View attachment 2448283

 

[B y r o n]

Also, make sure your heater is on to get the water out of there. Pick up a container of radiator flush and follow the directions on the container.

 

[cws57]

Good morning, thanks for the tips. I'll try and find the block plug. I don't have a heater and am in the process of installing one.

 

[SteveH]

You will likely get ~2 gal. from the radiator and ~2 gal. from the block. You only need to fill/drain/flush until clear water comes out. I have never seen any non-acid 'radiator flushes' remove anything, except money from my wallet.

You can also just use a garden hose for the first few passes, and worry about using distilled water (and coolant) for the long haul. These systems aren't much beyond old tractors as far as sophistication.

 

[cws57]

Steve: Good morning. "money from my wallet"....indeed!! Thanks for the tip. After I get it flushed it's onto installing the heater, which I have many questions about.

 

[cws57]

Steve: How long should I keep the engine running?

 

[SteveH]

You can run the engine with the petcock(s) open and a hose sticking into the radiator (or attached at a flush and fill tee), but you might just fill it completely with water, put the cap on, and drive it until the thermostat opens (full hot), then let it cool and drain it. When what comes out looks like clean water, you're ready to refill with 50/50 AF and distilled water. Good idea NOT to install the heater into the system until it's fully clean.

 

[Igotmearedone]

I've had to flush it a few times in the past year, mainly because I've had to remove the radiator for other things. I had to work a lot on the engine block plug to declog the 40 years of sludge. Then when that was unclogged, the plug bolt itself was in rough shape and caused a leak. Ended up buying a cock and plug combo from @ToyotaMatt. Not sure if any of it was necessary since I didn't have overheating issues, but it was pretty satisfying to see it flowing like a river in my last flush.

 

[1969FJ]

View attachment 2448322

Is there any way you can provide the full part number for this part. I certainly need to get one if still available, thanks.

 

[lions66]

I was advised it is better to remove the bottom radiator hose then the petcock on the radiator as these can get stuck or fail to reseal. Particularly if dirty or the radiator is old. As has been mentioned the plug on the block will also drain a lot of coolant.

 

[cws57]

I managed to get the engine block pet cock loosened pretty easy. I expect I am going to have to flush a few more times as I am from seeing clear water coming out.

 

[GA Architect]

Is there any way you can provide the full part number for this part. I certainly need to get one if still available, thanks.

Toyota part number: 96431-03833

 

[jengel199]

I’m new here. I followed this process. I drained my 1976 2F, using the engine plug, filled with flush, topped with water, ran engine a few days, opened engine plug while filling engine with clean water. Replaced plug. Topped off radiator with water. Now, with a radiator full of nothing but clean water after 10 minutes of idling the temperature Is still only warm to touch. The temperature gauge has gone from below C to about C after 10 minutes and the new 180 degree thermostat hasn’t opened up. Why? How long should it take idling for the engine to get up to temperature and open that thermostat? I attach a photo of the new thermostat installed.

 

[Green Bean]

Did you burp your system? i.e., get all of the trapped air out. They can be real buggers.

 

[DylanH239]

I followed this step from a different thread and it worked well for me when I flushed my cooling system in my 1977 FJ40 I used a no spill funnel from the autoparts store and it made the process pretty easy.

“12. Open up your radiator cap and set it to the side. Place a funnel over the radiator and fill it. Keeping the radiator cap off, start your truck and move the interior heat setting to high but keep the fan to off or low depending on your vehicle’s controls. Monitor the coolant level in your radiator it will take a little while for your engine to heat up. Up to 10-15 min depending on climate etc. Once it does the thermostat will open and the coolant lever in the radiator will drop. Top it off once it does and monitor for a few more minutes to make sure all the air bubbles are out of your coolant system. Turn off the engine and install your radiator cap. Then top off your coolant over flow bottle (if it needs it) and you are done.

Check again in 50 miles. Top off if needed.”

 

[South Texas 97]

I did exactly that, and in addition pump some of the hoses when the engine is hot. Use a rag or something as the hoses are hot. It works well.

 

[Green Bean]

One of these helps.

 

[jengel199]

I removed the thermostat, put it in boiling water on my stove and watched it open and close. Next I drained all the water out of the block, replaced the drain plug, filled the radiator with 3 gallons exactly of antifreeze. That’s all it would take. And replaced the thermostat. What concerns me is the 2F engine should hold between 4 and 5 gallons. And, running the car up the street a mile and back made the heater pipes warm, not hot, and when I checked the radiator level it never dropped. It’s 37 degrees out tonight so at least I am running with antifreeze now instead of water but the temperature isn’t that hot and the antifreeze level isn’t dropping. Maybe I have to give it more than 10-15 minutes in this weather? Does anybody else think the fact that after draining the water from the block the engine should accept more than 3 gallons of antifreeze?