Radiator fan activation temp

[NMBurb02]

At what temperature do radiator fans normally kick on? I was surprised by the wide swings in coolant temp readings on the analog gauge in the instrument panel of the GP, so when I took it out for a spin today I hooked up my OBD II reader and monitored the coolant temp on a digital gauge. Outside temp was about 50 F and the coolant temps would settle at about 185-190 F (halfway between the small and large ticks on the instrument panel gauge) while going 65 mph on the freeway. As soon as I exited, the temp would slowly creep up. I pulled into a gas station and idled at the pump for a while and watched the coolant temp creep up even further. It hit 200 without the radiator fans kicking on...210 (large tick on the instrument panel gauge)...215...217! Finally at about 220, the fans started up, quickly bringing the temp down to 210. I am used to the Burb, whose mechanical fan doesn't allow the coolant temps to get above 200 F, even in stop-and-go traffic with 90+ F outside temps, so am unsure if there is an issue here.

Is 220 F before the fans kick on normal? Could the ECU be programmed wrong? Should I take it in to get looked at?

 

[NHGUY]

That sounds about right.Todays vehicles run very hot,and if it was set to 200 or so,it would be running all the time.RWD vehicles with clutch fans also have a thermostatic spring that senses a hot radiator and engages the clutch.

 

[expat]

Agree, it's about right. 220F is a little over boiling point at sea level atmospheric pressure. your system is invariably pressurized, so you have a fare margin before you boil up.

As far as your engine is concerned, within reason, the hotter the better.

 

[Chris142]

Most gm's turn the low speed fan on @226 and the high speed fan @235.

 

[Roadkingnc]

Normal operation

 

[The motor guy]

I got a buddy who has a chevy 1500. He was letting it idle in my driveway while i was talking to him and it got up to 210. I was like isn't it getting a little hot? He was like ummmm.... no it's normal.

 

[ls1mike]

That is fine. Since my S/C 3800 is modified I have a 160 thermostat in there, It is rare that my fan comes on.

 

[Corvette Owner]

The following is the Corvette C5 (1997-2004) cooling fans operation:

C5 Cooling Fans Operation

The low speed cooling fan is commanded on when the coolant temperature reaches 108°C (226°F). It is turned off if the coolant temperature lowers to 104°C (219°F). The high speed cooling fan is commanded on when the coolant temperature reaches 113°C (235°F). It is turned off if the coolant temperature lowers to 108°C (226°F). When the A/C is on and the coolant temperature reaches 85°C (185°F), the low speed cooling fan will be turned on at vehicle speeds less than 56 kPh (35 mph).

 

[SwampSurvivor]

Depends on how hot the engine is desgined to run.

 

[NMBurb02]

Originally Posted By: Corvette Owner
The following is the Corvette C5 (1997-2004) cooling fans operation:

C5 Cooling Fans Operation

The low speed cooling fan is commanded on when the coolant temperature reaches 108°C (226°F). It is turned off if the coolant temperature lowers to 104°C (219°F). The high speed cooling fan is commanded on when the coolant temperature reaches 113°C (235°F). It is turned off if the coolant temperature lowers to 108°C (226°F). When the A/C is on and the coolant temperature reaches 85°C (185°F), the low speed cooling fan will be turned on at vehicle speeds less than 56 kPh (35 mph).

Thanks! That seems pretty consistent with what I was seeing. I guess I failed to mention that I was not running the A/C. And I remembered the fans running while at idle when I took a look under the hood after a short drive before buying the car, but the A/C was probably on then.

 

[dailydriver]

Originally Posted By: Corvette Owner
The following is the Corvette C5 (1997-2004) cooling fans operation:

C5 Cooling Fans Operation

The low speed cooling fan is commanded on when the coolant temperature reaches 108°C (226°F). It is turned off if the coolant temperature lowers to 104°C (219°F). The high speed cooling fan is commanded on when the coolant temperature reaches 113°C (235°F). It is turned off if the coolant temperature lowers to 108°C (226°F). When the A/C is on and the coolant temperature reaches 85°C (185°F), the low speed cooling fan will be turned on at vehicle speeds less than 56 kPh (35 mph).


Yes, and with a DiabloSport Predator/Trinity/In Tune programmer one can adjust these settings to whatever they want, to accomodate; weather conditions, mods, etc., as a stand alone parameter to ANY tuner (including the factory tune), without changing anything else.

One of the things I LOVE anout mine.

 

[lexus114]

I think my 85 Cavalier wagon I had many years ago came on @ 230? I checked it with my buddies scanner because I was concerned the fan never seemed to kick on. Of course I was not satisfied with that and I installed an after market temp sensor that worked off of the radiator hose. 230?, too hot for me.

 

[Hokiefyd]

Based on how my Cadillac used to run, and based on what others have confirmed here, 226 deg F is when the fans started, on low speed. High speed was at 234 deg F. At 220 deg F, yours may have even come on a touch early.

This is exactly why gauges on instrument panels are programmed to read "straight up" for any value between about 185 deg F and about 225 deg F. The temperature gauge on my Cadillac wouldn't move off straight up until about when the fans started on low speed. But it would climb quick above that, alerting the driver to a warm condition (but not yet cautionary).

Highest I saw on that car was 239 deg F.

 

[morris]

by running modern engines at much higher temps than we did in the past, it helps keep water out of the crankcase. and most if not all acids are water, helping engines last longer

 

[NMBurb02]

Originally Posted By: Hokiefyd
Based on how my Cadillac used to run, and based on what others have confirmed here, 226 deg F is when the fans started, on low speed. High speed was at 234 deg F. At 220 deg F, yours may have even come on a touch early.

This is exactly why gauges on instrument panels are programmed to read "straight up" for any value between about 185 deg F and about 225 deg F. The temperature gauge on my Cadillac wouldn't move off straight up until about when the fans started on low speed. But it would climb quick above that, alerting the driver to a warm condition (but not yet cautionary).

Highest I saw on that car was 239 deg F.

I'm used to analogue gauges doing that too, so I was a bit concerned about the GP's bouncing all over the place. I think it is actually pretty accurate. I watches the analogue gauge rise about one inch while idling at the gas station after the freeway run.