Overheat problem on small port 4AGE

stuttgart
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Overheat problem on small port 4AGE

Postby stuttgart » Mon Mar 14, 2022 10:03 pm

Looking for some help here...I have a JDM red top small port with over heating problem. At cold start the temperature would stay normal (60C / 150F) for approx 10min and then rapidly raise to 105-120C / 220-250F. I've install a new themostat, also tried remove it entirely, both with same result. Tried bleed the system by open the radiator cap and park car on a slope, I can see coolant spill out when rev engine to 2-3k rpm, is that normal? Seeking for advice to how to troubleshoot the issue. Thank you!

davew7
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Re: Overheat problem on small port 4AGE

Postby davew7 » Tue Mar 15, 2022 5:59 am

Sounds like a head gasket. Do a compression test or leak down test. Typically cylinders number 3 or 4 are the ones that fail.
Do not use a cheap replacement head gasket. Use Toyota or band name like Fel-Pro headgasket.
davew7

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Jinsoku
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Re: Overheat problem on small port 4AGE

Postby Jinsoku » Wed Mar 16, 2022 3:07 pm

Compression Test
For some reason pressure pushing the coolant out so now we have to figure out the cause.
compression test will be your go to at this point.

If its a Head Gasket, make sure to have the head inspected when at the machine shop.
HOPE its a HG and not a warped Head!
Since 2001

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jondee86
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Re: Overheat problem on small port 4AGE

Postby jondee86 » Wed Mar 16, 2022 4:40 pm

stuttgart wrote:I can see coolant spill out when rev engine to 2-3k rpm, is that normal?

If the engine is warmed up (thermostat open) with the radiator near full, you will see the coolant
circulating in the top tank when you have the engine idling. This is normal. Rev the engine and the
coolant level will "surge" and rise up a bit due the pump speed increasing. This is normal. If the
coolant is filled up to the neck, then when you rev the engine, some may spill out. This is normal.

If you have a blown head gasket, there will be combustion gases getting into the cooling system
and you will see a lot of small bubbles in the coolant "fizzing" like when you open a warm can or
bottle of soda. The gases will likely pump a decent amount of coolant out of the neck each time
you rev the engine and the coolant will smell of exhaust.

Cheers... jondee86
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