Engine overheating?

Tiny
TONYMAKALINAW
  • MEMBER
  • 2005 INFINITI G35
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 52,000 MILES
As I'm driving, the temperature gauge on my 2005 Infiniti G35 just started to rise and fall from normal to near the top of the gauge, triggering the cooling fans. It doesn't appear to be overheating but it never did this before. Coolant level is correct, serpentine belt is fine, and the water pump is not making any noise.

Bad coolant temp sensor? Thermostat? Any ideas?
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Wednesday, October 7th, 2009 AT 5:05 PM

24 Replies

Tiny
IMPALASS
  • EXPERT
Hello,

It sounds like the coolant temperature sensor needs to be replaced. Here are two guides to go through and the location of the sensor below.

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

and

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Check out the diagrams (Below). Please let us know what happens.
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Wednesday, October 7th, 2009 AT 9:13 PM
Tiny
TONYMAKALINAW
  • MEMBER
I went to Autozone, there are no codes displayed, everything seems to be okay. After driving for a while, with the engine hot, I checked under the hood, and noted the following: the coolant in the reservoir is at the proper level, but cold. The upper radiator hose is hot, but the lower one is cold. Very little heat coming out of the vents with the heat turned all the way up. The temp gauge spikes up close to the top but the car doesn't seem to be overheating. The gauge fluctuates up and down from center to top slowly but frequently.

Any ideas?

Thanks
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Thursday, October 8th, 2009 AT 3:09 PM
Tiny
IMPALASS
  • EXPERT
Hello,

It sounds like the water pump or thermostat needs to be replaced. Here are two guides to help walk you through the process.

https://www.2carpros.com/articles/replace-thermostat

and

https://www.2carpros.com/articles/water-pump-replacement

Let me know

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Thursday, October 8th, 2009 AT 10:38 PM
Tiny
TONYMAKALINAW
  • MEMBER
I checked everything. It was none of the above. Took it to a mechanic, he simply purged the air out of the cooling system and everything is fine.
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Friday, October 9th, 2009 AT 3:40 PM
Tiny
IMPALASS
  • EXPERT
Hello -

That is great to hear, air getting trapped does make the engine act funny. Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers
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Friday, October 9th, 2009 AT 4:51 PM
Tiny
DWIGHTMAN
  • MEMBER
  • 2003 INFINITI G35
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 192,000 MILES
On warm days (usually over eighty degrees) my engine will begin to overheat when I am sitting in traffic. If I turn off the A/C the temperature will stabilize and I can keep within the operating range but it is on the high end of the scale. If I turn the A/C back on the temperature will begin to rise. I do not notice this as much on the open highway but if the outside temperature is up over ninety degrees, the engine temperature will push up to the high side of the scale even in highway driving. Turning off the A/C is the only way to keep within the operating range. When I am sitting in traffic at a red light, I can here the fans kick on so I am pretty sure the fans are operating when called for. I have had the coolant checked at Infiniti dealer and they are telling me it checks okay. Would the thermostat be the problem?
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
KHLOW2008
  • EXPERT
Hi dwightman,

Thank you for the donation.

There are a few possible causes for the problem :

1. Cooling fan. The cooling fan operates at different speed for cooling and if it is not working at the highest speed when the temperature is high, the efficiency is insufficient. However this would not be a likely cause as at cruising speed the moving air should be able to cool the radiator to lower the temperature reading.

2. Radiator partially clogged. If the radiator is clooged partially, cooling efficiency would be reduced causing high temperature reading. When this occurs, the higher the speed the higher would the be temperature reading.

3. Bad thermostat. It could be stuck in partially open position resulting in reduced coolant movement that would cause the temperature to rise.

4. Insufficient coolant. When engine is cold, remove the radiator cap and check if the coolant level is at the neck. Check the reserve tank coolant level.

5. Bad water pump. This would reduce the coolant flow efficiancy.

From the above, item 2 and 3 would be the most probable cause.
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
MRTWELVEVOLTS
  • MEMBER
Did you ever fix it? I am having the same exact problem?

Thanks
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
ELIOTT PUGA
  • MEMBER
I have the same problem with my Infiniti. It gets overheating went I turn the A/C on. Why?
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
ROL*S.
  • EXPERT
Hi Eliott,

Were radiator cooling fans running when A/C was turned on? If so, did you notice temperature getting hot while on the freeway or on the streets. Also, A/C temperature was nice and cold the whole time?
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
EMJO
  • MEMBER
  • 2003 INFINITI G35
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 16,000 MILES
My car started intermittently overheating. On three occassions now, the temperature gauge has gone up to within a few tick marks of the first heavy hot line. (Half way from center, to almost touching).

I do not see exhaust in the coolent resorvoir

I do not see white smoke from the tail pipe

Keeping the car in motion keeps it cool where it is supposed to be.

When the temp gauge goes up, the AC blows warm air

When I see the gauge go up, I turn off the car for a few moments, then the next time I start it, it is working fine.

This occurs when the outside temperature gauge in the car reads 92 or hotter.

When engine temperature gauge is showing the correct temperature, the AC is cooling great and the AC fans are blowing hard

When the engine temperature gauge is showing hot, and the AC is blowing warm or hot air, then the AC fans are running slower.

There is no apparent loss of coolant

I do notice an extremely faint smell sometimes of hot coolant, but it is so faint, I am not sure of it. I do not see any measurable loss from the coolant resorvoir or any leak marks on the engine or in the exhaust.

Special note: my ac is on automatic because the control panel is damaged and needs to be replaced. As a consequence the control buttons do not work. (They want 2900 dollars to replace that control panel)
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
DOCFIXIT
  • EXPERT
Hi
Open hood engine running A/C on do cooling fans come on? When car heats up confirm fan operation.
Let me know
Thanks for donate
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
EMJO
  • MEMBER
Thanks for getting back to me so quickly. I assume by cooling fan you mean the fan in front of the radiator. Is that correct?
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
DOCFIXIT
  • EXPERT
That is correct suspect intermittent operation causing heat up
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
EMJO
  • MEMBER
Ok, thanks for clarifying that.

I will watch it over the next couple of days. It may take a day or two before it heats up again. I will watch it while he air is working, and then when it heats up again, take a peek and give you the results.

I appreciate your patience.
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
CARMAN8212
  • MEMBER
  • 2004 INFINITI G35
  • 100,000 MILES
It overheats head gasket not cracked
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Have a leak down test performed to verify head gaskets.

How long did you drive it overheated?

Roy
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
CARMAN8212
  • MEMBER
Not long I check the oil no sign of head gasket blown
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
That is not always a good indicator. You need the leak down test.

Roy
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)
Tiny
CARMAN8212
  • MEMBER
Havent drove it over heated just enough to know it gonna over heat
I park it home soon as.I bleed the radiator and it started up but didnt take long for it to start over heating also I only filled to the with water to bleed air
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Thursday, November 1st, 2018 AT 6:32 PM (Merged)

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