1HZ overheated, now changing gasket


New Member
I am in tunisia
May 9, 2019
Hi All,

7 months ago I changed all the cylinder head components (valves, seals, shims, etc...) due to multiple unsuccessful valves adjustment (found out that the valves were soldered on top by the previous owner to add height).

long story short, I replaced a new original Toyota radiator recently and installed a new thermostat and voila, the engine started to buildup high pressure on the coolant hoses and overheated twice (didn't reach the red mark on the dash).

After that, I removed the thermostat, changed the water pump, replaced the radiator cap, no luck, still overheating and building pressure, so it was time to check the cylinder head.

Today we disassembled the cylinder head and as you can see in the attached pictures, that the exhaust was leaking into the coolant passages, also, almost all coolant passages were clogged.

so here are my questions:
is it possible to resurface the same cylinder head and install it again?
is there any way to prevent rust in the blocks and coolant passages and how to remove it?




cheers for any advice thanks, ilyes

20190509_114836.jpg 20190509_114859.jpg 20190509_130410.jpg 20190509_114841.jpg 20190509_114847.jpg 20190509_130430.jpg

Paul Thompson

New Member
Dec 29, 2019
Yes of course you can resurface the head, and use it over and over. But....., have it cracked tested and while they are at it, they'll check to see its not warped, and if it is, it can be machined back to true so long as it doesn't involve shaving past the limit. The answer to your second question is yes, use 'rmi 25', as often as you want. After entering it into the cooling system/radiator, put some miles on it, flush it, then repeat it a week later, you'll be surprised by what it removes. Flushing the radiator is good management, (placing the hose into the lower radiator hose connection, and allow it to push up and out of the disconnected top hose, removing large particles that might be sitting on top of the cores) because the system cools by entry of engine heated fluid into the top hose and exit of radiator cooled fluid into the motor via the bottom hose, leaving debris that mightn't be able to pass through the cores.


Well-Known Member
I am in romania
May 23, 2012
Comarnic, Romania
After you’ve finished with all the flushing, use genuine Toyota red coolant, it’s got lubricants in it for the benefit of the water pump seals and rust inhibitor to stop that build-up.
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