Car Overheats When Idling / Shut Off

[Reid Nelson]

Hello There,

Car Information:
1995 Toyota 4Runner SR5
3.0L V6 Engine
4 Speed Auto w/ OD

No Recent Applicable Service.

I am having a problem with my 4Runner where if you leave the car running at idle for any appreciable amount of time (5-10 Minutes Max) it will begin to get hot, and overheat. I have noticed from a cold start the vehicle does heat up rather quickly. The overheating issue sometimes happens more after you’ve been driving it for a while. I have checked the coolant condition as well, and it is in great shape protecting down to -34 Degrees. I also don’t think it is the cooling fan as these vehicles have a belt driven fan although it could the fan clutch I’m not really sure.

I appreciate any help in trying to figure this out.

Thanks

Topic

[Richard Kirshy]

Possible causes:
Restricted air flow through the radiator
Faulty thermostat
Faulty water pump or impeller
Faulty fan clutch
Restricted coolant flow through the radiator

[Billy]

The easiest thing to check is the fan clutch. When idling, is the fan spinning? The quick heat up suggests this is not your problem.

Then the radiator air flow. Are there a bunch of leaves and stuff between the condenser and the radiator?

Next, how quickly does the upper radiator hose get hot? How hot does it get? What about the lower hose?

Are you certain all the air is out of the system?

[Ole Eggers]

[quote=”nightflyr” post=188853]Possible causes:
Restricted air flow through the radiator
Faulty thermostat
Faulty water pump or impeller
Faulty fan clutch
Restricted coolant flow through the radiator[/quote]

^^ What he said.

[Mike]

How old are the rad hoses?

The bottom rad hose usually has a spiral-wound metal stiffener inside it, preventing the hose from collapsing. (The bottom hose is usually connected to the “suction” side of the pump, and the hose naturally wants to collapse as coolant is being pulled through it.) Over time, the stiffener can rot away, allowing the hose to pinch shut when coolant is flowing.

A quick easy check: with the engine cold and not running, grab the bottom rad hose about half way along its length. Squeeze firmly. If the internal stiffener is OK, you shouldn’t be able to collapse the hose.

[Author]

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