Overheat Question

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Feb 20, 2011 | 03:39 PM

micscott

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Trailering

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From: The Big Valley

Overheat Question

I have a 2000 Expedition 4X4 5.4L.

Original issue was overheating (240 degrees), shown on the guage on my diagnostic tool.

So, I've drained & flushed the cooling system, changed the thermostat, waterpump, drivebelt, and couple of pulleys.

I also ran water from the hose, with left side block plug removed. water seemed to flow well.

I didn't notice any oil in the coolant and no coolant in the oil.

My diagnostic tool is a program called Autodiag which runs on a Palm Tungsten T. There are many parameters I can check. However, I'm not sure what else to look for.

Any advice?

Thanks,
Mike

Feb 20, 2011 | 04:02 PM

Big Greenie

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Is it still overheating? Does it overheat at low speed or high? How hot is it getting?

Feb 20, 2011 | 10:36 PM

micscott

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Trailering

Joined: Mar 2004

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From: The Big Valley

Quote:

Originally Posted by Big Greenie

Is it still overheating? Does it overheat at low speed or high? How hot is it getting?

It is still overheating, up to about 240 degrees. Gauge shows just below the red.

Originally it got hot on a trip to the store which is about 2 miles away, speeds between 25 and 45mph.

After all the changes it got hot while idling. I did not drive it more than around the block because I didn't want to get stuck out on the road.

Also forgot to mention, fan seems to be working fine, pulling air through the radiator.

Thanks,
Mike

Feb 21, 2011 | 07:16 AM

Big Greenie

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I was concerned about the fans performance. If the fan clutch is working properly, and you are seeing temps that high, the clutch should lock and the fan should ROAR as you rev it up, it should move huge amounts of air through the radiator.

Even though it probably isnt the cause, and wouldn't matter much at low speeds, is the radiator clear? Lots of times debris can collect between the AC condensor and the radiator blocking airflow.

Make sure you have all of the air out of the system from the flush as well.

I am leaning towards the fan clutch...

Feb 22, 2011 | 08:24 PM

alloro

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From: 0,0,1

Quote:

Originally Posted by micscott

After all the changes it got hot while idling.

Since there was a chance in symptoms after you did the work, then it's possible you either got a bum t-stat from the store, or you mistakenly installed it with the spring up instead of down.

Feb 24, 2011 | 10:24 AM

micscott

Thread Starter

Trailering

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From: The Big Valley

Quote:

Originally Posted by Big Greenie

Thank you. I really had not checked the fan clutch as thoroughly as you describe. I did check and clean a very small amount of debris between the condensor and radiator. I'm sure it was not an issue. I'm fairly confident air was out of the system.

Quote:

Originally Posted by alloro

Since there was a chance in symptoms after you did the work, then it's possible you either got a bum t-stat from the store, or you mistakenly installed it with the spring up instead of down.

Thanks, I did verify that the thermostat was operating properly and was installed correctly. I usually take photos as I'm working just in case there is an issue or I question myself.

So I took it to the mechanic yesterday and they noted the same symptoms I had, but they have a tool that allows them to see how hot the motor was while they were diagnosing. Anyway, the block, heads, etc didn't show the heat that the gauge and computer showed. Turns out the temperature sensor was bad. He replaced and said it is working well now. This is why I never heard that fan roar, since it really wasn't getting that hot.

Thanks for the help and advice,
Mike