1997 4runner sr5 230k

flushed the radiator and block
burped the system - my driveway has a steep incline

gutted the thermostat for more flow during the hot summer months and will replace it once cooler days arrive

so here is the history:

Repo'd the 4runner from my wife's nephew

radiator was half full and it was full of rust and water

back flushed the system until i got pretty close to clear water
added simple green and water to the radiator and burped the system.

She ran great and temperature gauge barely hit the 1/4 mark

4 days later decided it was time to drain and flush the simple green

simple green did a great job of cleaning out the block and radiator

flushed until i got clear water again

this time filled with antifreeze and water

filled the block thru the top radiator hose as i have read here in the forum.

Then added water

bolted everything up and burped again

so here is the problem........

Temperature reading is at half now and today on the freeway she overheated.

Drained the system and filled again......same process

thought maybe the water pump was damaged so i revved the engine and antifreeze shot out of the radiator neck. So the water PUMP is fine

squeezed both upper and lower radiator hoses and antifreeze came up out of the radiator neck.

Yes- the heater was set to high - both front and rear heaters

what am i missing here??

Did the simple green ruin the radiator??

Any help is appreciated

thank you - thank you - thank you

Temp should be at just below half on the gauge. 1/4 is not normal. I'd put the thermostat back in. It's part of the design. Without it the coolant may be passing through the rad too quick and not cooling enough. Check the cap as well.

Burp the system.

I've never had to burp anything that was in good operating condition.

On the toy I fill with antifreeze until it's about 1/4" from top of hole then start engine with heat control on max heat so the heater core fills. When antifreeze expands and starts to push out the filler neck I put on the rad cap. Then I top off the overflow tank and squeeze the upper rad hose to push the air out of the overflow line.


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Agree with this. the thermostat was placed there to regulate the temperature of the engine coolant, both while in the engine and in the radiator.

if you decide to return the thermostat, don't forget to position the jiggle valve correctly.

replace the thermostat, burp it, then let drive it. if it overheats on highways then the hg is blown, if it overheats all over then its another cooling issue or the hg is far beyond blown

I'm a bit confused why you would put a substance in the cooling system that EATS aluminum. Simple Green is safe to use to quickly clean aluminum, but it eats it if you leave it on aluminum. Let's hope you didn't cause any permanent damage.

If the cooling system (and engine) are in good shape, removing the removing the thermostat will make the engine run worse, too cold (yes, even in summer) and cause low MPG and ruin cats, etc. Many guys on here live in the desert and run an OEM thermostat with zero overheating issues. Get an OEM thermostat in there with the jiggle valve at 6 o'clock. (yes, upside down from how most engines have it installed)

-Charlie

Thanks for all your replies guys

I am gonna get the new stat and toyota red coolant tomorrow for sure.

Replaced the radiator this morning and she is running fine.

Temp gauge is at just below half so thank you kball for adding that note - i was a little nervous while test driving since the needle was at almost half thinking she was gonna overheat again.

@phattyduck
i read here on the forums that someone posted that they had used simple green to flush their system and it worked. I only found out last night that my assumptions were correct and i should not have used simple green at all. My $140 mistake.

Thanks for the info about not running a thermostat and ruining the cats !!

Thanks to all of you guys for your help!!

makes sense will add this in when i put the tstat back in

thanks

good info @Chingpo05 no gravy in the oil and the coolant is clearso i am saying a prayer

thanks for the info!

The needle just below halfway tells you the engine is between ~160*F and ~220*F. You'll need a Scangauge or aftermarket gauge to really know what the engine temp is...

-Charlie