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I have a 2006 gmc sierra with 5.3 engine is it normal for…

I have a 2006...

I have a 2006 gmc sierra with 5.3 engine is it normal for the coolant fans to kick on when temp is over 210 with a.c. off

Mechanic's Assistant: How many miles on the car? How has your mileage been lately?

240,000 engine recently replaced current engine has 170,000 miles runs good no check engine light are any thing just seem like the fans are not coming on soon enough

Mechanic's Assistant: Are you fixing your Sierra yourself? What have you tried so far?

Checked coolant level changed temp sensor an check fan relays

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

Seems to me that the low speed is not coming on for the coolant fan

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Answered in 1 minute by:
11/15/2017
Gary
Gary, ASE Certified Technician
Category: GMC
Satisfied Customers: 18,019
Experience: GCM master tech over 25 years
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Welcome! My name is ***** ***** I will do my best to assist you with this problem.

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that is actually normal temp for it to kick on

how long have you owed it ?

how hot will it ever get ?

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Customer reply replied 8 months ago
I owned it about 2 months it will only go about 2 lines past half but I previously owned a 2005 Yukon that never reached 210 under no condition

this engine was designed to run like this

the warmer they run them the better the emissions

this is the normal temp and when the fan should lick on

there is nothing wrong with this truck

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Customer reply replied 8 months ago
Then why would the Yukon run cooler same engine same cooling system

hard to say

more than likely the Yukon has a lazy T-stat that is opening too early causing it to run a little cooler

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Customer reply replied 8 months ago
I've owned several gm trucks an suv this is the first one I seen go over 210 I'm gonna bring it to the dealer tomorrow an let them check it if they say that's normal I'm going to sell it because I know it's not
Eric
Eric, Automotive Repair Shop Manager
Category: GMC
Satisfied Customers: 34,933
Experience: 20+ yrs. experience as repair shop manager and technician.
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HI,

Different expert here. I show the low speed cooling fan should come on at approximately 202 degrees. See below from service manual

Cooling Fan Control - Two Fan System

The engine cooling fan system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a series/parallel configuration that allows the powertrain control module (PCM) to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood fuse block.

During low speed operation, the PCM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the low speed fan relay coil, closes the relay contacts, and supplies battery positive voltage from the low fan fuse through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the cooling fan s/p relay and the right cooling fan. The result is a series circuit with both fans running at low speed.

During high speed operation the PCM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. After a 3 second delay, the PCM supplies a ground path for the high speed fan relay and the cooling fan s/p relay through the high speed cooling fan relay control circuit. This energizes the cooling fan s/p relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the high speed fan relay coil is energized closing the relay contacts and provides battery positive voltage from the high fan fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have there own ground path. The result is a parallel circuit with both fans running at high speed.

Important: The right and left cooling fan connectors are interchangeable. When servicing the fans be sure that the connectors are plugged into the correct fan.

The PCM commands the low speed cooling fans ON under the following conditions:
^ Engine coolant temperature exceeds approximately 94.5°C (202°F).
^ A/C refrigerant pressure exceeds 1447 kPa (210 psi).
^ After the vehicle is shut OFF if the engine coolant temperature at key-off is greater than 101°C (214°F) the low speed fans will run for a minimum of 60 seconds After 60 seconds, if the coolant temperature drops below 101°C (214°F) the fans will shut OFF. The fans will automatically shut OFF after 3 min. regardless of coolant temperature.
The PCM commands the high speed fans ON under the following conditions:
^ Engine coolant temperature exceeds approximately 104.25°C (220°F).
^ A/C refrigerant pressure exceeds approximately 1824 kPa (265 psi).
^ When certain DTC's set.
At idle and very low vehicle speeds the cooling fans are only allowed to increase in speed if required. This insures idle stability by preventing the fans from cycling between high and low speed.

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Eric
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