“Normal” Head, Intake, outside Temperature Range

[Ole Texan]

2018 Mustang GTA10, completely factory stock, 11,532 miles. Purchased used with 9252 miles 9/30/21.

outside temp 34* Speed 45-55 mph Head temp 198-203. Intake 38-42
same situation but stopped at two red lights (1 to 1.5 minutes)
Head temp 204-208. Intake 40-47
Resume driving head temp drops to 202. Intake drops to 45

outside temp 68* Speed 45-55 Head temp 204-208. Intake 78-82
same situation but stopped at two red lights (1 to 1.5 minutes)
Head temp 218-222. Intake 88-92
Resume driving head temp drops to 203. Intake stays 88

Fan does not turn on until Head temp is 218. Head temp continues to increase to 222 then will drop to 203. If I increase speed gently to 65 head temp will drop to 198-203.
intake may drop to 84

If continue to drive in above pattern head temp cycles between 198 and 222.
Intake stays 18 to 20 above outside temp.

Have not been in any higher than 68 outside temp. All driving is in Drive and would be considered normal.

Is this a normal set of temp ranges? Little concerned when outside temperature starts into 80-90s.

Thanks for any feed back..

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[WildHorse]

Why are you so concerned about temps ? Worry only if you see the coolant/oil temps go into the red.

 

[ice445]

Nothing about that is abnormal really. Worth considering two things, one is that these engines run warm for maximum efficiency, which is why the fan kicks on seemingly so late. Secondly, you have active grille shutters with a base model that blocks off airflow for further efficiency at speed. Both of these items keep the head temps higher than you'd think they should sit at. The car only cares about coolant temp though, which is typically 10-15F below cylinder head temp. Although it will start caring if you hit 240 or higher by cutting power and such. Anything under 230 is irrelevant on these cars. 230's under extreme conditions are OK unless you're sitting at that all day.

As a final note, in the summer you'll probably see lower temps overall since the A/C fan is always running to eject heat from the condenser, which means the shutters have to stay at least partially open and there's consistent airflow over the rad.

 

[kz]

Have you checked coolant level ?

IMO these temperatures are abnormal. I always have a cylinder head temp on the dash, only time it reaches 218-ish is during subsequent autocross runs (WOT / redline in 2nd gear) and it takes several in warm weather for engine to heat soak. I do have a larger radiator though if your car is not a performance pack one.

 

[ice445]

Have you checked coolant level ?

IMO these temperatures are abnormal. I always have a cylinder head temp on the dash, only time it reaches 218-ish is during subsequent autocross runs (WOT / redline in 2nd gear) and it takes several in warm weather for engine to heat soak. I do have a larger radiator though if your car is not a performance pack one.

Looks like he has a base car, so smaller rad. The PP rad is good for at least 10F less all the time, more in demanding situations (I upgraded to it). PP cars also have no shutters so you're always getting full airflow. When I was stock I saw similar trends to what he's seeing, although I'm at 4500 feet which murders the cooling ability of any radiator.

 

[KingKona]

Totally normal.

IATs vary massively depending on atmospheric variables.

 

[EFI]

Is this a normal set of temp ranges? Little concerned when outside temperature starts into 80-90s.

The target head temp is 212*, so yes those are normal and they won't go much higher even in the 90s.

 

[Ole Texan]

Thanks for feedback. Car is a base with stock radiator, correct fluid level and slates. I am not overly concerned, just have not experienced this level of head temperature shifts.

 

[EFI]

just have not experienced this level of head temperature shifts.

Well head temperature is usually alot more volatile than coolant temp as any little change in driving style would almost instantly show up as a change in head temperature as you are experiencing. Coolant takes longer to heat up/cool down and doesn't have the same swings as the head itself. I can only assume most other cars you had dealt with previously had coolant temp readings, not head temp.

 

[KingKona]

Thanks for feedback. Car is a base with stock radiator, correct fluid level and slates. I am not overly concerned, just have not experienced this level of head temperature shifts.

You've had other vehicles that displayed head temps?

 

[Ole Texan]

Had 2006 GTO 6.0 Ls with head temp sensor on each head. Car was set up for drag strip and limited street use.

I am aware that head temps change at a faster rate than water temps. Just seems my GT head temps fluctuate rapidly under normal driving conditions. Will wait for hot weather to see what happens.

 

[EFI]

Had 2006 GTO 6.0 Ls with head temp sensor on each head.

Was that engine modified to specifically read cylinder head temp and have 2 of them?

LSs (including my LS2 GTO) have one temp sensor in the driver's side head and it's set to read coolant temp not the actual cylinder material.

 

[Ole Texan]

After market head temp sensor, not water temp. One on each head, two readout gauges.

 

[EFI]

After market head temp sensor, not water temp. One on each head, two readout gauges.

How was it installed to read metal temperature vs. water? Just curious as I have been out of the LS game for a few years and I was not aware you could read metallurgy temperature in the LS head.

 

[Ole Texan]

Don’t know it worked, but aluminum sending unit bolted against rear of head with wiring to digital gauge.

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