Topic: 87 4runner running hot *UPDATED*

[Gnarly4X]

... a very plugged radiator....

As we all know, overheating a 22 can be mean a head job at the very least.  Overheating it few just a few seconds can warp an alloy head or blow a head gasket.

Coolant maintenance, like oil changes, should be done. You can buy coolant testers real cheap to check the effectiveness.  But changing and flushing your system every 20,000 or will go along ways to prevent an overheating problem. T-stats are inexpensive and easy to replace.

A 50/50 mix with DISTILLED water is recommended.  Ethylene Glycol has rust inhibitors and also acts as a lubricant, so running pure water can toast a water pump very quickly.  It also raises the boiling point of the mixture.  You can run up to 70/30 (70% coolant) if running in extreme cold weather.  Running pure ethylene glycol goes the other direction and lowers the boiling point and will raise the freeze temperature…. No bueno.

With the price increases in auto parts, the $150 NAPA copper radiator I bought about 17 years ago, now is about $300+, so obviously it pays to preserve your vehicle with diligent maintenance. 

Gnarls.

[blackdiamond]

As we all know, overheating a 22 can be mean a head job at the very least.  Overheating it few just a few seconds can warp an alloy head or blow a head gasket.

Coolant maintenance, like oil changes, should be done. You can buy coolant testers real cheap to check the effectiveness.  But changing and flushing your system every 20,000 or will go along ways to prevent an overheating problem. T-stats are inexpensive and easy to replace.

A 50/50 mix with DISTILLED water is recommended.  Ethylene Glycol has rust inhibitors and also acts as a lubricant, so running pure water can toast a water pump very quickly.  It also raises the boiling of point of the mixture.  You can run up to 70/30 (70% coolant) if running in extreme cold weather.  Running pure ethylene glycol goes the other direction and lowers the boiling point and will raise the freeze temperature…. No bueno.

With the price increases in auto parts, the $150 NAPA copper radiator I bought about 17 years ago, now is about $300+, so obviously it pays to preserve your vehicle with diligent maintenance. 

Gnarls.

Keeping in mind that $150 could have bought a house 17 years ago and $300 now is closer to a gallon of fuel!

Being serious, I think every 1% more of water is supposed to translate to about 1 degrees cooler temperatures.

[Mario]

When was the last time the water pump was changed? I know you have not had the 4runner very long but if the person that owned it before you, replaced the head gasket and not the water pump, that might be the issue. Everyone is right to look for leaks first, because if your cooling system cannot develop a good vacuum, your coolent flow will suffer. Start simple, radiator cap, Leaks, and last item would be the water pump.