FJ40 coolant flush

[JKIII FJ40]

Great thread! City Racer is one source for a resistor, this is if the low speed isnt working OEM 12V Heater Blower Resistor for '74 and later Land Cruiser FJ40 FJ45 FJ55 - https://www.cityracerllc.com/products/oem-12v-heater-blower-resistor-for-74-and-later-land-cruiser-fj40-fj45-fj55-hj47
Another thread (and the approach I took) Builds - The Architect's '77 FJ40 - https://forum.ih8mud.com/threads/the-architects-77-fj40.825413/page-7

 

[Ozpall]

I just replaced my tstat but can't get it to stop overheat on the gauge now. My bottom hose of the rad is not getting hot either.

 

[RevISK]

You probably still have air in the system.
Unless you forgot to install the top gasket on the t stat.
And the you probably still have air in the system.

Did you drain the block too? That looks pretty gnarly so it is also likely that you have a blockage and didn’t flush well enough.

 

[Ozpall]

You probably still have air in the system.
Unless you forgot to install the top gasket on the t stat.
And the you probably still have air in the system.

Did you drain the block too? That looks pretty gnarly so it is also likely that you have a blockage and didn’t flush well enough.

I'm gonna drain the block next it does looks gnarly.

 

[RevISK]

I'm gonna drain the block next it does looks gnarly.

Mine was brutal. It took many flushes to break it up. After 5 x 5 gallon jugs of flush I thought I had it but I wasn’t able to add the proper amount of coolant. Then something else dislodged and a whole bunch more gunk came out and after a few more flushes I had it about as clean as possible.

The biggest mistake I made was not replacing all my coolant lines then. Sprung a leak a month or two later and had to re-drain the system and dove deep to replace every hose and fitting. And then the burp Olympics began again.

 

[Ozpall]

Mine was brutal. It took many flushes to break it up. After 5 x 5 gallon jugs of flush I thought I had it but I wasn’t able to add the proper amount of coolant. Then something else dislodged and a whole bunch more gunk came out and after a few more flushes I had it about as clean as possible.

The biggest mistake I made was not replacing all my coolant lines then. Sprung a leak a month or two later and had to re-drain the system and dove deep to replace every hose and fitting. And then the burp Olympics began again.

I'm thinking about removing my waterpump just to inspect all that area as well and give it a good cleaning and if need be order a new pump.

 

[RevISK]

I'm thinking about removing my waterpump just to inspect all that area as well and give it a good cleaning and if need be order a new pump.

Good call. I didn't and hope I don't regret it.

 

[Ozpall]

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

I opened mine while cold and nothing came out, what's the safest way to do this? Is it OK while is some what warm?
Edit, It came out at last

 

[Green Bean]

I opened mine while cold and nothing came out, what's the safest way to do this? Is it OK while is some what warm?
Edit, It came out at last

View attachment 3631386

On ours, I had to remove the block drain and use a pick to pry/loosen the plugged up debris that was clogging up the opening. This thread describes how far you can safely go:

Block Drain and Drain Plug Removal

Thanks for all the advise. Great pictures of tools to help me today. Will make a run to the hardware store for the fittings to try a combo air/water approach. I did get some sediment under the thermostat from my 50 psi approach yesterday that I did not think did anything. I have removed...

forum.ih8mud.com

Post #29

 

[Ozpall]

Looks clean now

 

[sleepycruiser]

When I did a flush I used one of these with good results. https://www.amazon.com/gp/product/B000F5ECRW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

It was a little startling to see the amount of crud that came out.

I also used this stuff to try and clean everything out. https://www.amazon.com/gp/product/B00JJ1FB28/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

The final step was opening up the engine drain plug which was clogged. Had to do a Roto Rooter-type of procedure to get things flowing. Then replaced with new OEM cock.
View attachment 3533511
View attachment 3533512

Was that both parts of the drain petcock for the block?? Or does the existing block bolt go into that petcock?

 

[Green Bean]

Was that both parts of the drain petcock for the block?? Or does the existing block bolt go into that petcock?

Part # 96431-532 includes both parts.